tag:theconversation.com,2011:/us/topics/traffic-jam-6819/articlesTraffic jam – The Conversation2023-05-09T13:34:32Ztag:theconversation.com,2011:article/2044952023-05-09T13:34:32Z2023-05-09T13:34:32ZAir pollution is a hidden pandemic in Africa - tips on how to reduce your exposure and help combat it<figure><img src="https://images.theconversation.com/files/524381/original/file-20230504-25-q92t5q.jpg?ixlib=rb-1.1.0&rect=4%2C0%2C2943%2C1909&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Children and elderly people are vulnerable to air pollution. Photo by Pius Utomi Ekpei/AFP.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/school-boy-walks-past-smokeand-fumes-emitted-from-a-dump-in-news-photo/635231222?adppopup=true">from www,gettyimages.com</a></span></figcaption></figure><p>Rapid urbanisation in Africa is worsening air pollution levels. There are economic as well as health consequences. </p>
<p><a href="https://www.thelancet.com/action/showPdf?pii=S2542-5196%2821%2900201-1">Air pollution</a> threatens human health, health systems and economic activity. It is the <a href="https://www.stateofglobalair.org/sites/default/files/documents/2022-10/soga-africa-report.pdf#page=3">second leading risk factor for death</a> across Africa, contributing to an estimated 1.1 million deaths on the continent in 2019. </p>
<p>The continent has an urban population of <a href="https://www.afdb.org/en/documents/africas-urbanisation-dynamics-2022-economic-power-africas-cities">over 500 million</a>. This is projected to be over <a href="https://www.statista.com/statistics/1267863/number-of-people-living-in-urban-areas-in-africa/#:%7E:text=The%20urban%20population%20on%20the,reach%20722%20million%20by%202026.">700 million by 2026</a>. In the face of such enormous numbers and a seemingly insurmountable problem, it can feel difficult for ordinary people to protect themselves or make a difference. </p>
<p>But, as we found in our research, many strategies are possible. We have drawn up a list of suggestions, divided into three categories: practical tips to reduce exposure, how to keep your community air quality cleaner and, lastly, what steps policy makers can take.</p>
<h2>Air pollution’s many threats</h2>
<p><a href="https://www.sciencedirect.com/science/article/pii/S0160412022006365">Our research</a> highlights the fact that air pollution is a multifaceted and complex issue to tackle. Intervening can span different ministries such as transport, environment and health. Acting on one sector can affect a different sector, so it is important to clarify the role and responsibilities of all actors. </p>
<p>To formulate solutions and strategies that are acceptable and feasible to the general public, multiple stakeholders must collaborate: policy makers, civil society, communities, and academia. </p>
<p>Our findings show that much time can be saved by not ‘re-inventing the wheel’ and learning from implementers on the opportunities and barriers to tackle air pollution in cities. </p>
<p>We found that most strategies (83%) being used to tackle air pollution focused on household air pollution compared to outdoor air pollution (17%). This is even though outdoor air pollution is increasing due to urbanisation. </p>
<p>Overall, the strategies focus on technology (75%), more than on policy (20%), and even less on behavioural change (5%). </p>
<p>Our findings point to the need for more policy interventions. There are some obvious gaps in present approaches. These include policies that address changes in peoples’ behaviour. Another example is addressing major sources of pollution such as vehicles and two and three wheel motorcycles. Only 6% of all strategies applied in African contexts focus on decreasing air pollution through transport yet the continent is faced with a large increase of “used” (second-hand or pre-owned) vehicles.</p>
<p>Based on our insights, we’ve come up with the following list of practical tips. </p>
<h2>Practical tips to reduce exposure</h2>
<p>These four suggestions will go some way to protecting your health.</p>
<ul>
<li><p>Avoid exercising outdoors when pollution levels are high. If possible, exercise indoors during this time. </p></li>
<li><p>Avoid exercising near high-traffic areas.</p></li>
<li><p>Avoid having children and other vulnerable groups such as elderly people with asthma) where there’s cooking. This is particularly true if solid biomass fuels like firewood, charcoal, dung and crop residues and being used as fuel.</p></li>
<li><p>Ensure home cooking areas are properly ventilated, especially for homes using solid biomass fuels.</p></li>
</ul>
<figure class="align-center ">
<img alt="Trucks in a traffic jam on a busy highway" src="https://images.theconversation.com/files/524128/original/file-20230503-18-dkvkhs.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3690%2C2440&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524128/original/file-20230503-18-dkvkhs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524128/original/file-20230503-18-dkvkhs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524128/original/file-20230503-18-dkvkhs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524128/original/file-20230503-18-dkvkhs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524128/original/file-20230503-18-dkvkhs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524128/original/file-20230503-18-dkvkhs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Road traffic is a serious cause of air pollution in African cities. Photo by Olukayode Jaiyeola/NurPhoto.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/ariel-view-of-apapa-sea-port-in-apapa-lagos-nigeria-on-30-news-photo/1179097853?adppopup=true">from www,gettyimages.com</a></span>
</figcaption>
</figure>
<h2>How to keep the air in your community cleaner</h2>
<p>You can take some steps that will have a wider impact. </p>
<ul>
<li><p>Avoid open trash burning</p></li>
<li><p>improve solid waste management at both the household and community levels.</p></li>
<li><p>Promote awareness-raising activities around the importance of breathing clean air in cities.</p></li>
<li><p>Encourage your local businesses, community and city leaders and your policy makers to take air pollution seriously. You can do this by organising advocacy groups or support public online platforms that report real time levels of air pollution to increase accountability</p></li>
<li><p>Promote efforts to raise health literacy about how air pollution increases diseases such as asthma and stress.</p></li>
<li><p>Request education modules in schools for children and young people to be sensitised and to gain knowledge about air pollution</p></li>
<li><p>Buy from businesses that follow air quality guidelines and aim for net zero targets </p></li>
<li><p>Engage in active travel (walking and cycling) whenever possible to decrease transport-related emissions</p></li>
</ul>
<h2>What your policy makers can do</h2>
<p>You can also play an active role in getting policy makers to take concrete steps. </p>
<ul>
<li><p>Set standards and guidelines to replace obsolete technologies with clean and environmentally friendly ones.</p></li>
<li><p>Get communities involved in local interventions to decrease air pollution. </p></li>
<li><p>Promote policies that don’t allow anyone to smoke indoors and support measures to make all public places tobacco-free.</p></li>
<li><p>Provide forms of non-motorised transport to increase active lifestyle, physical activity and reduce emissions.</p></li>
<li><p>Support the installation of sensors to collect air quality data and monitor the pollution levels.</p></li>
<li><p>Communicate daily air pollution forecasts to let people know when the air is unhealthy in the community. This can be through local radio and TV weather reports, newspapers and through community WhatsApp groups.</p></li>
<li><p>Introduce cleaner-burning fuels and improved stoves that burn solid fuels more efficiently.</p></li>
</ul>
<h2>Conclusion</h2>
<p>By considering these tips and strategies, communities and leaders have the opportunity to beat air pollution, the invisible pandemic beneath our noses.</p>
<p>The air we breathe represents the living space and the quality of life we all need for a healthier and more sustainable planet, including for generations unborn.</p><img src="https://counter.theconversation.com/content/204495/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr. Okello Gabriel works at the University of Cambridge Institute for Sustainability Leadership and his Research Fellowship is funded by a philanthropic donation from AstraZeneca. The views expressed in this publication are those of the author and not necessarily those of AstraZeneca. He is affiliated with African Centre for Clean Air. </span></em></p><p class="fine-print"><em><span>Meelan Thondoo does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Air pollution accounts for many deaths in Africa yearly. However, this may change if people learn to protect themselves and hold their leaders accountable.Gabriel Okello, Prince of Wales Global Sustainability Fellow, University of CambridgeMeelan Thondoo, Research Associate, MRC Epidemiology Unit, University of CambridgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1839442022-06-14T14:37:53Z2022-06-14T14:37:53ZAir pollution in fast-growing African cities presents a risk of premature death<figure><img src="https://images.theconversation.com/files/468341/original/file-20220611-18059-dln7lp.jpg?ixlib=rb-1.1.0&rect=28%2C0%2C4682%2C3142&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Road traffic is one of the causes of air pollution in Lagos, Nigeria.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/motorists-queue-in-a-chaotic-traffic-gridlock-following-news-photo/1142442342?adppopup=true">Photo by Pius Utomi Ekpei/AFP via Getty Images</a></span></figcaption></figure><p>Ten more African cities have signed on to the <a href="https://www.c40.org/news/african-cities-clean-air-declaration/">C40 Clean Air Cities Declaration</a> to improve air quality. C40 is an international group of mayors collaborating to make cities more environmentally sustainable. </p>
<p>In May 2022, Abidjan, Accra, Addis Ababa, Dakar, Ekurhuleni, Freetown, Johannesburg, Lagos, Nairobi and Tshwane joined Durban, the first African city to sign the declaration.</p>
<p>As part of the C40 pledge, city leaders have committed to actions to tackle air pollution and slow human-caused changes in climate. These include actions such as setting targets that follow the World Health Organisation’s clean air <a href="https://www.who.int/news-room/feature-stories/detail/what-are-the-who-air-quality-guidelines">guidelines</a>. </p>
<p>This is a welcome commitment, as air pollution is a leading burden on global health. More than <a href="https://doi.org/10.1016/S2542-5196(22)00090-0">6.5 million</a> people die prematurely from exposure to air pollution each year worldwide. And air quality is worsening in African cities during a period of rapid growth and development. African cities are forecast to grow by <a href="https://doi.org/10.1177/0956247816663557">3 - 31% annually</a> from now until the end of the century. This is far steeper than growth rates in Indian cities, at about 1 - 3% per year. </p>
<p>A major challenge in combating air pollution in Africa’s cities is the scarcity of data. Air quality <a href="https://www.sciencedirect.com/science/article/pii/S2590162119300437">is not monitored</a> in most cities and resources to compile inventories of the types and sizes of sources contributing to air pollution are lacking. All these efforts are costly and require sustained, long-term funding. </p>
<p>Publicly available data from <a href="https://acp.copernicus.org/articles/21/6275/2021/">satellite observations</a> provide a picture of multiple air pollutants. <a href="https://www.science.org/doi/10.1126/sciadv.abm4435">In our recent study</a>, we sampled these data over fast-growing cities in the tropics, including 26 in Africa. Our investigation covered a 14-year period between 2005 and 2018. </p>
<p>We determined that the quality of air is declining at unprecedented rates. We found that the cause is a shift from rural to urban sources and that combined worsening air quality and population growth is linked to 180,000 additional premature deaths. </p>
<p>Such harmful effects will persist without bold air quality policies.</p>
<h2>Shift in pollution</h2>
<p>For centuries, air pollution in Africa has been dominated by <a href="https://cp.copernicus.org/articles/9/289/2013/cp-9-289-2013.pdf">open burning of biomass</a>. This is a common practice by farmers in the dry season to clear land and to prepare for the next sowing season. The smoke produced is full of <a href="https://openknowledge.worldbank.org/bitstream/handle/10986/29504/124342-BRI-p153343-PUBLIC-march-22-9-pm-WB-Knowledge-Burning.pdf?sequence=1">pollutants</a>, bad for people and the environment.</p>
<p>This is now changing, in cities at least. </p>
<p>In our <a href="https://www.science.org/doi/10.1126/sciadv.abm4435">analysis</a> we identified that urban pollution sources have surpassed rural biomass burning as the main cause for worsening air pollution in cities. Satellite observations are too coarse (~10 km) to pinpoint the exact sources, but we can speculate that these include road traffic, burning of waste, and household use of fuels like <a href="https://pubs.acs.org/doi/abs/10.1021/acs.est.0c03754">charcoal</a> and wood. </p>
<p><a href="https://www.science.org/doi/10.1126/sciadv.abm4435">Our study</a> focused on the fastest growing cities in the tropics. Amongst these are Lagos (<a href="https://www.macrotrends.net/cities/22007/lagos/population">population 15.4 million people growing at 3.5% per year</a>) in Nigeria, Dar es Salaam (<a href="https://www.macrotrends.net/cities/22894/dar-es-salaam/population">population 7.4 million people, 5.1% per year</a>) in Tanzania, and Kinshasa (<a href="https://www.macrotrends.net/cities/20853/kinshasa/population">population 15.6 million people, 4.4% per year</a>) in the Democratic Republic of the Congo. </p>
<p>The air quality indicators we tracked were fine particulate matter pollution (PM2.5) and the gas-phase compounds nitrogen dioxide (NO2), ammonia (NH3), and volatile organic compounds (VOCs). These either directly impact health (PM2.5, NO2) or form air pollutants that do (VOCs, NH3). These can all be produced from traffic, and burning of household waste and fuel. </p>
<figure class="align-center ">
<img alt="Many people gathered together" src="https://images.theconversation.com/files/468344/original/file-20220611-31449-n1s348.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468344/original/file-20220611-31449-n1s348.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468344/original/file-20220611-31449-n1s348.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468344/original/file-20220611-31449-n1s348.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468344/original/file-20220611-31449-n1s348.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468344/original/file-20220611-31449-n1s348.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468344/original/file-20220611-31449-n1s348.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dar es Salaam has a population of 7.4 million people. Photo by Daniel Hayduk/AFP via Getty Images)</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/congolese-men-collect-plastic-bottles-on-the-edge-of-the-news-photo/967066148?adppopup=true">Getty Images</a></span>
</figcaption>
</figure>
<h2>Health hazards</h2>
<p>The shift from rural to urban sources, combined with rapid population growth, is leading to more people living in closer proximity to air pollution and worsening population health. </p>
<p>Of most concern is PM2.5, as these particles are about 30 times smaller than the diameter of a strand of human hair. PM2.5 penetrate deep into our lungs and go on to have a <a href="https://www.theguardian.com/environment/ng-interactive/2019/may/17/air-pollution-may-be-damaging-every-organ-and-cell-in-the-body-finds-global-review">range of effects on health</a>, leading to premature death. Most prominent are heart disease, stroke, chronic obstructive pulmonary disease, lung cancer, and lower respiratory infections. </p>
<p>We used health risk assessment and atmospheric chemistry models, along with the satellite data, to estimate that premature mortality from sustained exposure to these small particles has steadily increased in 21 of the fastest growing cities in Africa. It’s risen from <a href="https://www.science.org/doi/10.1126/sciadv.abm4435">84,000 in 2005 to 110,000 in 2018</a>. This is on average about 2,000 avoidable deaths each year. </p>
<figure class="align-center ">
<img alt="Map of some African cities" src="https://images.theconversation.com/files/468785/original/file-20220614-22-e9f42t.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468785/original/file-20220614-22-e9f42t.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=248&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468785/original/file-20220614-22-e9f42t.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=248&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468785/original/file-20220614-22-e9f42t.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=248&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468785/original/file-20220614-22-e9f42t.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=312&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468785/original/file-20220614-22-e9f42t.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=312&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468785/original/file-20220614-22-e9f42t.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=312&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Map showing premature deaths in cities studied.</span>
<span class="attribution"><span class="source">Karn Vohra</span></span>
</figcaption>
</figure>
<p>A third of these deaths are in five of the 10 cities that have signed on to the C40 declaration: Abidjan, Addis Ababa, Dakar, Lagos and Nairobi. The steepest increase in early deaths of about 300 people per year is in Kinshasa, a city yet to join the pledge. </p>
<figure class="align-center ">
<img alt="Many people gathered for a rally" src="https://images.theconversation.com/files/468345/original/file-20220611-43412-x1lmsw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468345/original/file-20220611-43412-x1lmsw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468345/original/file-20220611-43412-x1lmsw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468345/original/file-20220611-43412-x1lmsw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468345/original/file-20220611-43412-x1lmsw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468345/original/file-20220611-43412-x1lmsw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468345/original/file-20220611-43412-x1lmsw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Kinshasa is yet to sign the clean air cities declaration. Photo: John Wessels/AFP via Getty Images.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/congolese-men-collect-plastic-bottles-on-the-edge-of-the-news-photo/967066148?adppopup=true">Getty Images</a></span>
</figcaption>
</figure>
<p>The number of people dying prematurely from exposure to air pollution is three times lower in African cities than in Asia, where the shift to urban sources of air pollution is <a href="https://acp.copernicus.org/preprints/acp-2019-1122/acp-2019-1122.pdf">well under way or has already occurred</a>. This is in part because improvements in healthcare in Africa are counteracting the adverse effects of air pollution on health leading to decline in overall mortality. In Addis Ababa in Ethiopia, for example, the number of deaths could have been almost double the values we estimated without improvements in healthcare. But this offsetting won’t last if air quality continues to degrade and healthcare improvements taper off.</p>
<p>Twenty-six cities in Africa are <a href="https://journals.sagepub.com/doi/10.1177/0956247816663557">predicted to be megacities by 2100</a>, reaching unprecedented sizes. By 2100, Lagos may be home to 80 million people; more than double the current largest city of Tokyo. </p>
<p>Access to emission control and renewable energy technologies are cheaper and easier to use than ever before. The C40 pledges are a step in the right direction, but more cities need to join to safeguard public health across the continent.</p><img src="https://counter.theconversation.com/content/183944/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Karn Vohra received funding from the University of Birmingham Global Challenges Studentship.</span></em></p><p class="fine-print"><em><span>Eloise Marais receives funding from UK Research Councils, the European Commission, and the Stockholm Environment Institute. </span></em></p>Twenty-six fast-growing African cities may battle health challenges if air pollution is not addressed.Karn Vohra, Research Fellow, UCLEloise Marais, Associate Professor in Physical Geography, UCLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1732552022-01-19T13:26:13Z2022-01-19T13:26:13ZAfrican cities, COVID and climate: public knowledge on urban planning is needed<figure><img src="https://images.theconversation.com/files/441114/original/file-20220117-21-l52loh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A crowded marketplace amid the COVID-19 pandemic in Accra, Ghana.</span> <span class="attribution"><span class="source">CHRISTIAN THOMPSON/Anadolu Agency via Getty Images</span></span></figcaption></figure><p>African cities are rapidly <a href="https://population.un.org/wup/">urbanising</a> and already experiencing considerable <a href="https://theconversation.com/africas-cities-face-unique-risks-what-can-be-done-to-manage-them-78419">negative impacts</a> of urbanisation. The production of urban spaces in African cities is frequently characterised as unsustainable. </p>
<p>This is due to factors such as slum proliferation, haphazard development and traffic congestion. And also because of evolving socio-economic activities associated with urban spaces, like unregulated informal activities and increased poverty. This situation is compounded by global health pandemics such as COVID-19 and climate change. These are predisposing African cities to increased vulnerability, including flood events.</p>
<p>Urban planning has been identified as having the capacity to support sustainable urban development in African cities. It can foster healthier environments and lifestyles. It can create healthy and resilient cities. Yet, it has also been blamed for adding to urban problems. It does so through neglect, segregation and non-participation. </p>
<p>If the purpose of urban planning is for human and planetary health, then why not adequately engage with it to address urban development problems in African cities? In a recent <a href="https://journals.sagepub.com/doi/abs/10.1177/08854122211055800">paper</a> I argue that citizen engagement is key to improving the way Africa’s cities are planned. </p>
<h2>Troubled history</h2>
<p>The history of urban planning in Africa indicates that it was introduced during colonisation to address health problems in cities. It was a highly specialised technical activity performed by experts from Europe. There was little or no involvement of the cities being planned for. Decisions were largely an imposition of colonial ideals. </p>
<p>While it produced some benefits, such as addressing sanitation concerns, it was also used as a colonial tool of domination and control. It contributed to spatial and economic segregation. </p>
<p>In Ghana, urban planning was used to develop the resource-rich south while the north was left undeveloped. Similarly, in South Africa, urban planning was used during <a href="https://www.sahistory.org.za/article/history-apartheid-south-africa">apartheid</a> to create spatial segregation.</p>
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Read more:
<a href="https://theconversation.com/can-covid-19-inspire-a-new-way-of-planning-african-cities-145933">Can COVID-19 inspire a new way of planning African cities?</a>
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<p>After independence there was hope of reform. But unfortunately, colonial urban planning legislation and practices were adapted in post-colonial Africa to cope with the implications of burgeoning urbanisation, with limited practical reforms. </p>
<p>Today, most African cities are faced with the dilemma of developing more functionally integrated, spatially coherent, economically competitive, environmentally sustainable and socially inclusive urban environments. In the shadow of rapid urbanisation, what has emerged is unplanned and unregulated city growth and expansion, and with it increased poverty.</p>
<p>Major urban planning conflicts revolve around haphazardly growing informal settlements. These are characterised by poor sanitation services, congestion and ramshackle housing, often surrounded by indescribable filth. These unplanned and unserviced communities house nearly <a href="https://journals.sagepub.com/doi/abs/10.1177/08854122211055800">three-quarters</a> of Africa’s urban population.</p>
<h2>New approach needed</h2>
<p>Yet effective urban planning still seems an appropriate way to address these many urban development challenges in African cities. Especially in this era of urbanisation, climate change and increasing urban poverty. </p>
<p>In theory, urban planning should lead to the creation of much needed socioeconomic opportunities, both locally and nationally. At the same time it should provide a strong incentive to manage nature’s strongholds in a way that conserves them. </p>
<p>In reality, though, urban planning practices remain relics of colonisation. They are elitist and demonstrate limited inclusiveness. </p>
<p>Colonisation, rapid urbanisation and limited resources are often identified as contributing to poor urban planning. A new approach to urban planning is needed to restore hope in African cities.</p>
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<strong>
Read more:
<a href="https://theconversation.com/people-in-accras-slums-know-green-spaces-are-important-planners-should-take-heed-166296">People in Accra's slums know green spaces are important: planners should take heed</a>
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<p>There is limited focus on urban planning education among urban residents. There is limited public knowledge on what planning is and what benefits it offers. Similarly, research indicates poor public interest and participation in urban planning due to limited education. </p>
<p>My paper discusses three guidelines to improve planning knowledge among residents. These can help change the urban planning narrative on the continent.</p>
<h2>Three keys to a better future</h2>
<p><strong>1. Visibility</strong> </p>
<p>Poor visibility of urban planning is a major hurdle. Many ordinary residents in African cities do not know the value or purpose of urban planning. Agencies and city authorities should urgently improve urban planning visibility through mainstream and social media platforms. </p>
<p>For example, regular social media posts on the practice of urban planning in African cities can increase public knowledge. Mainstream media can support in educating the public on the importance of urban planning in local languages. A conscious engagement of local religious and tribal leaders on key issues can increase the knowledge levels and acceptance of urban planning in African cities. </p>
<p>It is only when urban residents understand urban planning that meaningful outcomes can be achieved.</p>
<p><strong>2. Local knowledge</strong> </p>
<p>Urban planning in African cities remains exclusionary. It is an act of the elites and practice of the professionals, with limited involvement of urban communities. This encourages apathy among residents. It puts them at the receiving end of whatever plans that evolved. </p>
<p>Valuing local knowledge and inputs in urban planning processes and practices means involving and respecting urban residents in all dimensions of urban development. It means reflecting community orientation in all its complexity. Especially those in informal settlements who often do not have an organised voice. </p>
<p>Valuing local knowledge and inputs in urban planning promotes transparency and accountability through collaboration. This is essential in addressing ongoing and emerging development issues such as climate change that affect all sectors of the urban economy. These sectors include social, economic, institutional, cultural, financial, environmental and physical or spatial components of the urban economy.</p>
<p><strong>3. The vulnerable</strong> </p>
<p>It’s important to identify and integrate vulnerable stakeholders and sectors in urban planning practice. This will improve public knowledge in two ways. </p>
<p>Firstly, it will ensure that all stakeholders receive adequate attention and become aware of urban planning capacity. Particularly the interests of weaker and vulnerable urban residents (like the elderly, the disabled and children) are often overlooked. Secondly, it will ensure adequate consideration for all sectors of the economy, including the informal sector, and will contribute to improved preparedness towards addressing critical challenges of climate change, urban poverty and rapid urbanisation. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/theres-a-disconnect-between-research-and-urban-planning-in-africa-how-to-fix-it-157113">There's a disconnect between research and urban planning in Africa: how to fix it</a>
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<p>Addressing issues of rapid urbanisation, climate change and persistent urban poverty in African cities may lie in the involvement of residents and their support for inclusive urban systems. Residents support for, and understanding of urban planning would contribute to inclusive and spatially integrated cities, and would provide sustainable and efficient living and working environments. </p>
<p>Without strong resident support and involvement, African cities may continue to prove highly problematic and undesirable for habitation in the future.</p><img src="https://counter.theconversation.com/content/173255/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Patrick Brandful Cobbinah has previously received funding from Lincoln Institute for Land Policy, USA. </span></em></p>A new approach to urban planning is needed to restore hope in African cities. There are three keys that can help unlock this.Patrick Brandful Cobbinah, Senior Lecturer, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1404082020-07-21T12:06:57Z2020-07-21T12:06:57ZWith fewer cars on US streets, now is the time to reinvent roadways and how we use them<figure><img src="https://images.theconversation.com/files/348046/original/file-20200716-15-sbnv15.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4031%2C3024&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">New priorities in Boulder, Colo.</span> <span class="attribution"><span class="source">Kevin Krizek</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Sticking closer to home because of COVID-19 has shown many people what cities can be like with less traffic, noise, congestion and pollution. Roads and parking lots devoted to cars take up <a href="https://www.theatlantic.com/ideas/archive/2020/04/pandemic-shows-what-cities-have-surrendered-cars/610423/">a lot of land</a>. For example, in <a href="https://transfersmagazine.org/magazine-article/valley-of-the-sun-drenched-parking-space/">Phoenix, Los Angeles</a> and <a href="https://nextcity.org/daily/entry/how-much-public-space-does-a-city-need-UN-Habitat-joan-clos-50-percent">New York City</a> these spaces account for over one-third of each city’s total area. </p>
<p>When stay-at-home orders went into effect in many parts of the U.S. in March, streets and parking lots went dormant seemingly overnight. Within days, municipalities across the U.S. started <a href="http://pedbikeinfo.org/resources/resources_details.cfm?id=5209">shifting these spaces</a> to other uses that better suit people.</p>
<p>As a professor of environmental design and transport, I’ve worked for decades to <a href="https://scholar.google.com/citations?user=lfb0Tu4AAAAJ&hl=en&oi=ao">unravel the many factors</a> that keep people reliant on cars, SUVs and trucks. Weather, time constraints, children – there are many reasons that prevent people from using transportation modes like bicycles. Yet with a simple first step – starting to reconfigure city streets – meaningful change can begin to break down traditional transportation barriers and usher in a new culture of getting around town by means other than cars. </p>
<h2>The dangerous, expensive automobile</h2>
<p>In large U.S. cities, nearly half of all car trips are <a href="https://doi.org/10.32866/10777">less than four miles</a>. Using cars to travel such short distances has many costs. </p>
<p>For example, consider traffic fatalities. Two pedestrians or cyclists die every hour on U.S. city streets, a national trend that’s been <a href="http://www.trb.org/Main/Blurbs/180624.aspx">worsening</a> in recent years, even though cycling and walking rates are <a href="https://bikeleague.org/content/new-data-bike-commuting">steady or declining</a>. Pollution from cars contributes to climate change and worsens air quality. Designing cities around cars <a href="https://theconversation.com/people-are-stranded-in-transit-deserts-in-dozens-of-us-cities-92722">marginalizes individuals who don’t have them</a>.</p>
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<figcaption><span class="caption">The COVID-19 pandemic offers an opportunity to radically change how cities worldwide use their streets.</span></figcaption>
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<p>In my view, this is the time to move beyond the “grab the keys” mentality on the way out the door, as <a href="https://doi.org/10.1080/01944363.2015.1057196">millennials</a> and <a href="https://washpirg.org/blogs/blog/usp/don%E2%80%99t-believe-hype-%E2%80%93-millennials%E2%80%99-transportation-habits-are-changing">GenXers</a> already are doing. <a href="https://www.nytimes.com/2020/07/09/opinion/ban-cars-manhattan-cities.html">New visions</a> for streets, where cars use less space and are replaced by smaller vehicles built for individual riders, are gaining currency.</p>
<p>These modes of transport might be <a href="https://electrek.co/2020/06/19/cityqs-enclosed-electric-car-ebike-begins-taking-pre-orders/">new forms of e-bikes</a>, e-scooters or hoverboards. These novel vehicles, which were already <a href="https://usa.streetsblog.org/2020/06/17/four-signs-this-might-be-micromobilitys-big-moment/">attracting attention</a> before COVID-19, complement conventional bicycles, whose <a href="https://www.nytimes.com/2020/05/18/nyregion/bike-shortage-coronavirus.html">sales have boomed</a> during the pandemic.</p>
<h2>New thinking, different results</h2>
<p>Increasingly, thinking about the future of cities suggests that chiefly relying on cars as a form of transport <a href="https://www.nytimes.com/2020/07/08/opinion/us-infrastructure-plan.html">has run its course</a>. By minimally modifying the existing infrastructure, it is possible for city leaders to repurpose roads and parking spaces while ensuring the same ease of being able to <a href="https://doi.org/10.1016/j.trd.2020.102336">reach daily services</a>. </p>
<p>Emerging forms of mobility and changing mindsets can help deliver these opportunities. Bicycles and bicycle-like vehicles provide a catalyst to shift how city streets are used. </p>
<p>Research demonstrates that people will adopt new ways of getting around town when they are confident that an entire route, including intersections and parking lots, is safe for travel. Some COVID-19-induced street changes that have emerged recently, such as <a href="https://globaldesigningcities.org/publication/global-street-design-guide/designing-streets-people/designing-for-motorists/traffic-calming-strategies/">reducing the number of traffic lanes</a> and <a href="https://www.insider.com/cities-closed-streets-for-pedestrians-covid-lockdowns-2020-5#eventually-new-york-city-aims-to-open-a-total-of-100-miles-of-streets-for-free-use-to-pedestrians-2">closing streets to traffic</a>, are a good first step. But they lack the network component.</p>
<p>Networks quickly develop the more people use them. The quickest way to build one that is scaled and purposed for people begins by identifying streets used to make short trips. These are places near neighborhood retail districts, schools and other activity centers. </p>
<p>Informed by local data, leaders can make decisions about which streets should give priority to vehicles such as bicycles, not cars. Changes might include physically demarcated lanes and signs making statements like “Cars are guests.” Initially, these changes might require waivers to exempt them from adhering to current engineering guidelines and standards – restrictions that stifle innovation. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1264305002203492352"}"></div></p>
<p>Now large and small U.S. cities are experimenting with different strategies and contending with long-standing equity concerns about <a href="https://www.nytimes.com/2020/07/20/upshot/pandemic-city-planning-inequality.html?action=click&module=Spotlight&pgtype=Homepage">which streets</a> to change. For example, Minneapolis has <a href="https://www.minneapolisparks.org/news/2020/04/03/minneapolis-park-and-recreation-board-announces-three-more-parkway-closures-to-motor-vehicles-to-allow-pedestrians-more-space-for-social-distancing/">closed a number of parkways to cars</a>, reserving them exclusively for cyclists and walkers. </p>
<p>Pioneering cities like <a href="https://bikeportland.org/2020/04/29/heres-what-to-expect-with-portlands-new-slow-streets-plan-314117">Portland, Oregon</a>, <a href="https://www.seattle.gov/transportation/projects-and-programs/programs/stay-healthy-streets">Seattle</a> and <a href="https://www.oaklandca.gov/projects/oakland-slow-streets">Oakland</a> are using this time to test ways of sharing a broader array of streets among cyclists, walkers and car users. Researchers are providing tools to identify the most promising places to reallocate space for <a href="https://doi.org/10.32866/001c.13421">pop-up cycle ways</a>. </p>
<p>Enacting change now – in a strategic manner and while travel levels are down – may be an opportunity to reap <a href="https://twitter.com/BrentToderian/status/1280517484362129409">quick gains</a> with <a href="https://twitter.com/Jamesdestafford/status/1278735426312945664">high impact</a>. I believe that a better transport future is within reach by taking advantage of the space dominated by automobiles. This is the time to leverage current low-traffic conditions so that streets and roads can be converted to accommodate new technology and transport.</p><img src="https://counter.theconversation.com/content/140408/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kevin J. Krizek does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>City streets were built to accommodate cars, but the COVID-19 pandemic has scrambled our transport needs. Many cities are moving to make streets more people-friendly and less car-centric.Kevin J. Krizek, Professor of Environmental Design, University of Colorado BoulderLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1355512020-04-07T19:59:58Z2020-04-07T19:59:58ZTraffic jams are contagious. Understanding how they spread can help make them less common<p>Traffic jams may have disappeared from our roads as people stay home during the COVID-19 pandemic, but we can be confident they will be back. Scientists have studied traffic and congestion for decades. </p>
<p>We know a lot about how traffic jams form, how they spill from one road to another, and also how can we stop them happening and help cities recover. </p>
<p>Our research shows that traffic congestion spreads through a city like a disease. Using this insight we have created a simple model based on a contagion model often used to predict the spread of illness, which produces results quickly and can help traffic controllers respond in real time to traffic jams.</p>
<p>The study, carried out with colleagues at the University of California, Berkeley, and Johns Hopkins University, is <a href="https://www.nature.com/articles/s41467-020-15353-2">published in Nature Communications</a> today. </p>
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Read more:
<a href="https://theconversation.com/the-maths-of-congestion-springs-strings-and-traffic-jams-41684">The maths of congestion: springs, strings and traffic jams</a>
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<h2>Traffic history</h2>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/325259/original/file-20200403-74255-18exoaz.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/325259/original/file-20200403-74255-18exoaz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=419&fit=crop&dpr=1 600w, https://images.theconversation.com/files/325259/original/file-20200403-74255-18exoaz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=419&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/325259/original/file-20200403-74255-18exoaz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=419&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/325259/original/file-20200403-74255-18exoaz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=526&fit=crop&dpr=1 754w, https://images.theconversation.com/files/325259/original/file-20200403-74255-18exoaz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=526&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/325259/original/file-20200403-74255-18exoaz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=526&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Pioneering traffic researcher Bruce Greenshields using a movie camera to measure traffic flow in 1933.</span>
<span class="attribution"><span class="source">75 Years of the Fundamental Diagram for Traffic Flow Theory, Transportation Research Circular, Number E-C149, June 2011</span></span>
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<p>The first <a href="http://tft.eng.usf.edu/greenshields/docs/greenshields_1935_3.pdf">simple description of traffic flow</a> based on observations was published in 1933 by the American researcher Bruce Greenshields. This was only 25 years after the production of the first Ford Model T in 1908. </p>
<p>Greenshields used a movie camera to take consecutive pictures with a constant time interval to measure traffic. Since then, numerous data collection and modelling techniques have been developed. </p>
<p>Today, the most advanced method to measure and monitor traffic in cities uses anonymous location data from mobile phones with sophisticated mathematical and computer simulation models. The most recent example of such powerful data sources and analysis techniques are the <a href="https://www.google.com/covid19/mobility/">community mobility reports</a> recently released by Google, which show changes in mobility in cities around the world due to the spread of COVID-19.</p>
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<img alt="" src="https://images.theconversation.com/files/325266/original/file-20200403-74225-yk0rl3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/325266/original/file-20200403-74225-yk0rl3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=200&fit=crop&dpr=1 600w, https://images.theconversation.com/files/325266/original/file-20200403-74225-yk0rl3.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=200&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/325266/original/file-20200403-74225-yk0rl3.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=200&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/325266/original/file-20200403-74225-yk0rl3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=251&fit=crop&dpr=1 754w, https://images.theconversation.com/files/325266/original/file-20200403-74225-yk0rl3.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=251&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/325266/original/file-20200403-74225-yk0rl3.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=251&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The DynaMel model describes traffic flow in Melbourne.</span>
<span class="attribution"><span class="source">University of New South Wales (UNSW Sydney)</span></span>
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<h2>Big traffic, big computing</h2>
<p>Many existing models describe traffic well but require so much computational power that it is difficult to use them in real time for traffic control. In a large metropolitan area, these models often take tens of minutes or hours to run, even using cloud-based and other high-performance computing technologies. </p>
<p>While this may not sound like a big deal for transport planning purposes, it is actually one of the biggest hurdles for their use in practice for traffic operations and control. To overcome this challenge, scientists have more recently started searching for simpler ways of describing and predicting urban traffic congestion.</p>
<h2>Traffic jams are contagious</h2>
<p>Scientists use contagion models to describe the spread of an infectious disease in a population, as well as things like the spread of a computer or mobile phone virus through the internet and the spread of news or misinformation on social media. </p>
<p>We have shown that a similar modelling framework can be used to describe how traffic jams spread in cities. We adopted what is called the susceptible-infected-recovered (SIR) model, commonly used in epidemics, and applied it to traffic jams in Sydney, Melbourne, New York, Chicago, Montreal and Paris. </p>
<p>In the traditional model, epidemiologists divide a population into groups of people who are susceptible to a disease, people who are infected, and people who have recovered. In ours, we divide a road network into free-flowing roads, congested roads, and recovered roads.</p>
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Read more:
<a href="https://theconversation.com/traffic-is-complex-but-modelling-using-deceptively-simple-rules-can-help-unravel-whats-going-on-92833">Traffic is complex, but modelling using deceptively simple rules can help unravel what's going on</a>
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<p>Every road in the network belongs to one of these categories, and the state of traffic on each one can change over time. A free flow link might become congested and a congested link could become recovered as time passes.</p>
<p>Our new model shows that the spread of traffic congestion can be characterised with a universal measure similar to the basic reproduction number, known as <em>R</em><sub>0</sub> in the epidemic models. This number represents how quickly congestion spreads through a city, independent of the topology, urban form and network structure of the city.</p>
<p>We empirically verified our results with traffic data from Google and a <a href="https://www.sciencedirect.com/science/article/abs/pii/S1569190X18300558">computer simulation model</a> of the Melbourne metropolitan area.</p>
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<img alt="" src="https://images.theconversation.com/files/325277/original/file-20200403-74261-eqajna.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/325277/original/file-20200403-74261-eqajna.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=177&fit=crop&dpr=1 600w, https://images.theconversation.com/files/325277/original/file-20200403-74261-eqajna.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=177&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/325277/original/file-20200403-74261-eqajna.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=177&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/325277/original/file-20200403-74261-eqajna.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=223&fit=crop&dpr=1 754w, https://images.theconversation.com/files/325277/original/file-20200403-74261-eqajna.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=223&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/325277/original/file-20200403-74261-eqajna.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=223&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The model shows how congestion and recovery spread through a traffic network.</span>
<span class="attribution"><span class="source">University of New South Wales (UNSW Sydney)</span></span>
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<h2>How the contagion model can help</h2>
<p>The new findings can be used for adaptive and predictive control of congestion in cities. While the model does not specify which streets are congested, it provides aggregate information on what percentage of links in the network are congested. </p>
<p>This information can be used to develop control strategies to cut down how long the congestion lasts or to keep the number of congested roads below an acceptable threshold. </p>
<p>Potential congestion mitigation strategies that could benefit from these findings include perimeter traffic control of city centres, improving signal timing and removal of bottlenecks.</p><img src="https://counter.theconversation.com/content/135551/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The author does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A new model based on how diseases spread will help traffic controllers get on top of congestion fasterMeead Saberi, Senior lecturer, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/993472018-09-06T15:41:54Z2018-09-06T15:41:54ZWhen is it quicker to walk, than catch a bus?<figure><img src="https://images.theconversation.com/files/235232/original/file-20180906-190673-1efxija.jpg?ixlib=rb-1.1.0&rect=100%2C6%2C3640%2C2785&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/shadows-people-walking-manchester-uk-590385134?src=nXPe9rE49VfrgdrPWj2_0w-2-26">Shutterstock.</a></span></figcaption></figure><p>It can often be tempting to jump on a bus for a short journey through the city, especially when it’s raining or you’re running behind schedule. Where there are dedicated bus lanes in place, it can feel as though you speed past gridlocked traffic. But as city authorities begin new initiatives to get people walking or cycling, that could all change – and so could you.</p>
<p>British people are <a href="https://www.statista.com/chart/12828/the-uk-cities-with-the-biggest-traffic-jams/">wasting tens of hours in traffic</a> every year: London comes top, with the average commuter spending 74 hours in traffic, followed by Manchester, with 39 hours and Birmingham and Lincoln, both with 36 hours. </p>
<p>It might surprise some people to learn that cities are intentionally slowing down private vehicles, in order to shift people to other, more efficient, modes of transport. In fact, transport for London removed <a href="http://content.tfl.gov.uk/technical-note-10-what-is-the-capacity-of-the-road-network-for-private-motorised-traffic.pdf">30% of the road capacity</a> for private vehicles in central London between 1996 and 2010. That trend continues today, as the organisation gives over more space for buses, cyclists and pedestrians.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/229298/original/file-20180725-194134-1ufbb1g.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/229298/original/file-20180725-194134-1ufbb1g.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=329&fit=crop&dpr=1 600w, https://images.theconversation.com/files/229298/original/file-20180725-194134-1ufbb1g.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=329&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/229298/original/file-20180725-194134-1ufbb1g.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=329&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/229298/original/file-20180725-194134-1ufbb1g.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=413&fit=crop&dpr=1 754w, https://images.theconversation.com/files/229298/original/file-20180725-194134-1ufbb1g.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=413&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/229298/original/file-20180725-194134-1ufbb1g.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=413&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">London’s road capacity, over time.</span>
<span class="attribution"><a class="source" href="http://content.tfl.gov.uk/technical-note-10-what-is-the-capacity-of-the-road-network-for-private-motorised-traffic.pdf">Transport for London.</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Clamp down on cars</h2>
<p>The loss of road capacity for cars has occurred across most UK cities, but not on the same scale everywhere. The good news is that the changes, when made, appear to have reduced actual car congestion. It seems that by making it less attractive to use your car, you’ll be more likely to use other transport. In fact, the average speed of buses and cyclists can be up to <a href="http://content.tfl.gov.uk/2017-18-annual-performance-summary.pdf">twice as fast</a> as normal traffic in cities such as London. </p>
<p>The relationship between walking and improved health has been proven to such an extent that it seems everyone – your doctor, your family, regional and national government – wants to increase physical activity. <a href="https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002602">The savings</a> in health care costs, are via improved fitness, reduced pollution and improved mental health, and its impact on social care are huge. </p>
<p>For instance, Greater Manchester <a href="https://assets.ctfassets.net/nv7y93idf4jq/5NBNSoWRZS8AkcGkAU4CEg/f2dfea7defcc0699b2a11c7219b5254d/17-0663_GM_2040_Exec_summary.pdf">wants to increase</a> the number of people who get the recommended level of exercise (only about half currently do). The most advanced of these plans is London’s, which has the specific goal of increasing the number of walks people take by <a href="http://content.tfl.gov.uk/mts-walking-action-plan.pdf">a million per day</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/235231/original/file-20180906-190639-1ct6kli.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/235231/original/file-20180906-190639-1ct6kli.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/235231/original/file-20180906-190639-1ct6kli.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/235231/original/file-20180906-190639-1ct6kli.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/235231/original/file-20180906-190639-1ct6kli.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/235231/original/file-20180906-190639-1ct6kli.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/235231/original/file-20180906-190639-1ct6kli.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Buses lagging behind.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/london-uk-july-24-2018-cyclist-1156977820?src=wsKZvL7VqH-o1MUbdYt8ng-1-29">Alena.Kravchenko/Shutterstock.</a></span>
</figcaption>
</figure>
<p>So, the reality is that over the next few years, walking will gradually appear more and more “normal” as we are purposefully nudged towards abandoning our rather unhealthy, sedentary lifestyles. </p>
<h2>The long journey</h2>
<p>Consider this: the typical bus journey in the UK is <a href="https://www.statista.com/statistics/301038/average-bus-trip-distance-by-region-uk/">almost three miles</a>, with an average journey time of around 23 minutes. The equivalent walk would take approximately 52 minutes, travelling at <a href="https://www.bhf.org.uk/how-you-can-help/events/training-zone/walking-training-zone/walking-faqs">just over three miles per hour</a>. It seems obvious that the bus is much faster – but there’s much more to consider. </p>
<p>People normally walk at least a quarter of a mile to and from the bus stop – that’s roughly ten minutes. Then, they have to wait for a bus (let’s say five minutes), account for the risk of delay (another five minutes) and recover from the other unpleasant aspects of bus travel, such as overcrowding. </p>
<p>This means that our 23 minute bus journey actually takes 43 minutes of our time; not that much less than the 52 minutes it would have taken to walk. When you think of the journey in this holistic way, it means you should probably walk if the journey is less than 2.2 miles. You might even choose to walk further, depending on how much value you place on your health, well-being and longevity – and of course how much you dislike the more unpleasant aspects of bus travel. </p>
<p>The real toss up between walking and getting the bus is not really about how long it takes. It’s about how we change the behaviour and perceptions we have been conditioned to hold throughout our lives; how we, as individuals, engage with the real impacts that our travel decisions have on our longevity and health. As recent converts to walking, we recommend that you give it a go for a month, and see how it changes your outlook.</p><img src="https://counter.theconversation.com/content/99347/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>It can feel much faster to get the bus – but that could all be a matter of perspective.Marcus Mayers, Visiting Research Fellow, University of HuddersfieldDavid Bamford, Professor of Operations Management, University of HuddersfieldLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/928332018-06-07T20:28:00Z2018-06-07T20:28:00ZTraffic is complex, but modelling using deceptively simple rules can help unravel what’s going on<p><em>This is the fourth article in our series, <a href="https://theconversation.com/au/topics/moving-the-masses-54500">Moving the Masses</a>, about managing the flow of crowds of individuals, be they drivers or pedestrians, shoppers or commuters, birds or ants.</em></p>
<hr>
<p>Scientists, engineers and economists have used equations to solve real-world problems since the invention of basic addition and subtraction. Not sure how to price your apple harvest? Use a supply-and-demand equation to find the ideal price. It seems there’s an equation for everything in life. </p>
<p>Equations are great for modelling well-defined problems where the rules do not change, and as such have been the backbone of pure science. But in today’s ever-growing, fast-shifting society, many problems are too complex to model with a single equation. So how do we deal with complex phenomena such as traffic, the subject of this Conversation series? To that end, <a href="https://en.wikiquote.org/wiki/Discourse_on_the_Method">Descartes gave us a hint</a> many years ago:</p>
<blockquote>
<p>Divide each difficulty into as many parts as feasible and necessary to resolve it.</p>
</blockquote>
<p><a href="http://www.agent-based-models.com/blog/2010/03/30/agent-based-modeling/">Agent-based modelling</a> (ABM) is an approach that encapsulates this philosophy and has been gaining in popularity for the past decade. Instead of treating the problem as one entity, ABM looks at modelling the behaviour of each of the smaller elements (agents) within the system.</p>
<p>It is a bottom-up approach where macro outcomes are derived from the activities of individual micro actors. As the agents interact, you gain a better understanding of the system as a whole. </p>
<h2>So how does this work for traffic?</h2>
<p>Let’s take the example of a <a href="https://www.citylab.com/transportation/2013/09/fantastically-clear-concise-explanation-why-traffic-happens/6962/">traffic jam</a>. Conventionally, scientists have used sophisticated analytical approaches, such as <a href="https://www.wired.com/2010/06/st_equation_traffic/">equations</a>, that treat traffic like a flow of liquid. Interestingly, we can replicate the same traffic phenomena by modelling individual cars with two simple rules:</p>
<ol>
<li><p>If there’s a car in front of you, slow down.</p></li>
<li><p>If there aren’t any cars in front of you, speed up (while obeying the speed limit).</p></li>
</ol>
<p>These rules are essentially descriptions of what a rational person would do while driving. One could presume that to cause a traffic jam we would need an additional factor such as police checks or traffic accidents. Traffic jams do not just happen by themselves – or do they?</p>
<p>It turns out that those two rules are enough to naturally cause a traffic jam. A traffic jam can occur purely out of internal interactions between cars, and not because of any external factor. In this phenomenon, a <a href="https://www.newscientist.com/article/dn13402-shockwave-traffic-jam-recreated-for-first-time/">congestion “shockwave”</a> travels in the direction opposite to the direction of the cars. </p>
<p>Researchers from several Japanese universities recreated this phenomenon with real cars back in 2008, as shown in the video below.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Suugn-p5C1M?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A shockwave traffic jam recreated.</span></figcaption>
</figure>
<p>When an unexpected phenomenon results from the interactions between individuals (agents), this is called emergent behaviour. It is this unique property of agent-based modelling that gives it an advantage over conventional models.</p>
<p>Another benefit is that it is very intuitive to develop an agent-based model. Instead of having to understand the mechanics of traffic jams, all you need to do is define the rules that govern the behaviour of individual cars. It shouldn’t be too surprising that two high school students from Boston originally built the earlier traffic jam model more than 20 years ago. </p>
<p>A good example that demonstrates ABM’s intuitive nature is the modelling of flocking behaviour in birds. It’s <a href="https://www.sciencenews.org/article/birds-turns-match-math-quantum-matter">fantastically difficult</a> to model mathematically, but flocking behaviour can be replicated in agent-based modelling using <a href="http://www.cs.toronto.edu/%7Edt/siggraph97-course/cwr87/">three simple governing rules</a>: </p>
<p><strong>1. Separation:</strong> steer to avoid crowding local flockmates </p>
<p><img src="https://cdn.theconversation.com/static_files/files/155/01-Separation-v2.gif?1528257919" width="100%">
</p><figure><figcaption>Adapted from <a href="https://www.red3d.com/cwr/boids/" target="_blank">original graphic</a> by Craig Reynolds.</figcaption></figure><p></p>
<p><strong>2. Alignment:</strong> steer towards the average heading of local flockmates</p>
<p><img src="https://cdn.theconversation.com/static_files/files/157/02-Alignment-v2.gif?1528257919" width="100%">
</p><figure><figcaption>Adapted from <a href="https://www.red3d.com/cwr/boids/" target="_blank">original graphic</a> by Craig Reynolds.</figcaption></figure><p></p>
<p><strong>3. Cohesion:</strong> steer to move towards the average position of local flockmates.</p>
<p><img src="https://cdn.theconversation.com/static_files/files/156/03-Cohesion-v2.gif?1528257919" width="100%">
</p><figure><figcaption>Adapted from <a href="https://www.red3d.com/cwr/boids/" target="_blank">original graphic</a> by Craig Reynolds.</figcaption></figure><p></p>
<p>The resulting model is remarkably similar to real life. The three rules successfully bring out the emergent phenomenon of flocking behaviour.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/MvmN5o6dZ8s?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Daniel Shiffman’s implementation of Craig Reynold’s Boids program to simulate flocking. Each bird steers itself based on rules of avoidance, alignment and cohesion.</span></figcaption>
</figure>
<h2>From playful toy to policy tool</h2>
<p>In addition to traffic management, agent-based modelling has practical applications in other fields. For example, to understand how infectious diseases such as MERS spread through a city, the author has developed a large-scale <a href="https://www.informs-sim.org/wsc17papers/includes/files/233.pdf">ABM simulation</a> that models each individual living in his home town, Suwon, in South Korea. </p>
<p>The governing rules are simple: </p>
<ol>
<li>In the daytime, individuals go to work (or school, depending on their age) and interact with their colleagues (or classmates).</li>
<li>At night, individuals return home to spend time with their family.</li>
<li>Individuals can become infected when interacting with a sick person. </li>
</ol>
<p>Through this simple set of interactions, a vast network of secondary contacts is formed, through which a disease can spread. To ensure that the results represent the city accurately, we carefully selected each individual’s age, gender, family members, and home and work locations, to ensure that they matched regional census statistics on housing, labour and education. </p>
<p>The results revealed that prevention efforts should focus on key schools, where most of the disease spread takes place.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/213063/original/file-20180404-189801-w2wpb.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/213063/original/file-20180404-189801-w2wpb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/213063/original/file-20180404-189801-w2wpb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=254&fit=crop&dpr=1 600w, https://images.theconversation.com/files/213063/original/file-20180404-189801-w2wpb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=254&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/213063/original/file-20180404-189801-w2wpb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=254&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/213063/original/file-20180404-189801-w2wpb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=319&fit=crop&dpr=1 754w, https://images.theconversation.com/files/213063/original/file-20180404-189801-w2wpb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=319&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/213063/original/file-20180404-189801-w2wpb.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=319&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Close-up of Suwon city showing all residential buildings. Individuals spend their time with their family within each house, and interact with neighbours from nearby.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Beyond the above examples, ABM has practical applications in <a href="https://www.anylogic.com/a-pharmaceutical-company-used-agent-based-modeling-to-decide-on-a-marketing-strategy/">marketing</a>, <a href="https://ops.fhwa.dot.gov/trafficanalysistools/index.htm">traffic management</a>, and <a href="http://biomedicalcomputationreview.org/content/biology-interacting-things-intuitive-power-agent-based-models">biomedical</a> fields. As computational power increases, this modelling approach is limited only by imagination in its implementation and use. </p>
<hr>
<p><em>You can find other articles in the series <a href="https://theconversation.com/au/topics/moving-the-masses-54500">here</a>.</em></p><img src="https://counter.theconversation.com/content/92833/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Yohan Kim have received funding from National Research Foundation of Korea for his research on Suwon city.</span></em></p><p class="fine-print"><em><span>Jay Falletta and Scott Kelly do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>By identifying and applying the key rules governing the behaviour of each individual, agent-based modelling offers insights into complex phenomena like traffic jams and flocking.Yohan Kim, Research Principal, Institute for Sustainable Futures, University of Technology SydneyJay Falletta, Research Assistant, Institute for Sustainable Futures, University of Technology SydneyScott Kelly, Research Principal, University of Technology SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/953392018-06-07T10:53:48Z2018-06-07T10:53:48ZConnected cars can lie, posing a new threat to smart cities<figure><img src="https://images.theconversation.com/files/220363/original/file-20180524-51121-101woqz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">What algorithm turned these lights red?</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/traffic-lights-over-blue-sky-293647550">monticello/Shutterstock.com</a></span></figcaption></figure><p>The day when <a href="https://www.its.dot.gov/cv_basics/index.htm">cars can talk to each other</a> – and to <a href="https://www.its.dot.gov/pilots/">traffic lights</a>, stop signs, guardrails and even pavement markings – is <a href="https://www.its.dot.gov/pilots/cv_pilot_apps.htm">rapidly approaching</a>. Driven by the promise of <a href="https://www.cts.virginia.edu/wp-content/uploads/2014/05/Task2.3._CONOPS_6_Final_Revised.pdf">reducing traffic congestion</a> and <a href="https://www.its.dot.gov/press/2015/ngv_tech_announcement.htm">avoiding crashes</a>, these systems are already rolling out on roads around the U.S.</p>
<p>For instance, the <a href="https://www.its.dot.gov/pilots/pilots_mobility.htm">Intelligent Traffic Signal System</a>, developed <a href="https://www.its.dot.gov/research_archives/dma/index.htm">with support from the U.S. Department of Transportation</a>, has been tested on public roads in Arizona and California and is being installed more widely in <a href="https://www.its.dot.gov/pilots/pilots_nycdot.htm">New York City</a> and <a href="https://www.its.dot.gov/pilots/pilots_thea.htm">Tampa, Florida</a>. It allows vehicles to share their real-time location and speed with traffic lights, which can be used to effectively optimize the traffic timing in coordination with the real-time traffic demand to <a href="https://www.cts.virginia.edu/wp-content/uploads/2014/05/Task2.3._CONOPS_6_Final_Revised.pdf">dramatically reduce vehicle waiting time in an intersection</a>.</p>
<p><a href="https://sites.google.com/view/cav-sec/congestion-attack">Our work</a>, from the <a href="https://vhosts.eecs.umich.edu/robustnet/">RobustNet Research Group</a> and the <a href="http://traffic.engin.umich.edu/">Michigan Traffic Laboratory</a> at the University of Michigan, focuses on making sure these next-generation transportation systems are secure and protected from attacks. So far we’ve found they are in fact relatively easy to trick. Just one car that’s transmitting fake data can cause enormous traffic jams, and several attack cars could work together to shut down whole areas. What’s particularly concerning is that our research has found the weakness is not in the underlying communication technology, but in the <a href="http://dx.doi.org/10.14722/ndss.2018.23222">algorithms actually used to manage the traffic flow</a>.</p>
<h2>Misleading an algorithm</h2>
<p>In general, algorithms are meant to take in a variety of inputs – such as how many cars are in various locations around an intersection – and calculate an output that meets a particular goal – such as minimizing their collective delay at traffic lights. Like most algorithms, the traffic control algorithm in Intelligent Traffic Signal System – nicknamed “I-SIG” – assumes the inputs it’s getting are honest. That’s not a safe assumption.</p>
<p>The hardware and software in modern cars can be modified, either <a href="https://doi.org/10.1109/SP.2010.34">physically through the car’s diagnostic ports</a> or <a href="http://static.usenix.org/events/sec11/tech/full_papers/Checkoway.pdf">over wireless connections</a>, to instruct a car to transmit false information. Someone who wanted to compromise the I-SIG system could hack her own car using such methods, drive to a target intersection and park nearby.</p>
<p>Once parked near the intersection, we’ve found that the attacker could take advantage of two weaknesses in the algorithm controlling the light to extend the time a particular lane of traffic gets a green light – and, similarly, the time other lanes get red lights.</p>
<p>The first vulnerability we found, which we call “last vehicle advantage,” is a way of extending the length of a green-light signal. The algorithm keeps an eye on approaching cars, estimates how long the line of cars is and determines how long it thinks it will take for all the vehicles in a line of traffic to get through the intersection. This logic helps the system serve as many vehicles as possible in each round of light changes, but it can be abused. An attacker can instruct her car to falsely report joining the line of cars very late. The algorithm will then hold the attacked light green long enough for this nonexistent car to pass, leading to a green light – and correspondingly, red lights for other lanes – that is much longer than needed for the actual cars on the road.</p>
<p>We called the second weakness we found the “curse of the transition period,” or the “ghost vehicle attack.” The I-SIG algorithm is built to accommodate the fact that not all vehicles can communicate yet. It uses the driving patterns and information of newer, connected cars to infer the real-time location and speed of older, noncommunicating vehicles. Therefore, if a connected car reports that it is stopped a long distance back from an intersection, the algorithm will assume there is a long line of older vehicles queuing ahead of it. Then the system would allocate a long green light for that lane because of the long queue it thinks is there, but really isn’t.</p>
<p>These attacks happen by making a device lie about its own position and speed. That’s very different from known cyberattack methods, like injecting messages into <a href="https://www.techrepublic.com/article/no-surprise-iot-devices-are-insecure/">unencrypted communications</a> or having an unauthorized user logging in <a href="https://www.pcworld.idg.com.au/article/607908/iot-botnet-highlights-dangers-default-passwords/">with a privileged account</a>. Therefore, known protections against those attacks can do nothing about a lying device.</p>
<h2>Results from a misinformed algorithm</h2>
<p>Using either of these attacks, or both in concert with each other, can allow an attacker to give long periods of green lights to lanes with little or no traffic and longer red lights to the busiest lanes. That causes backups that grow and grow, ultimately building into massive traffic jams.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/3iV1sAxPuL0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A congestion attack on a traffic signal control system.</span></figcaption>
</figure>
<p>This sort of attack on traffic lights could be just for fun or for the attacker’s own benefit. Imagine, for example, a person who wants to have a faster commute adjusting his own traffic-light timing, at the expense of other drivers’ delays. Criminals, too, might seek to attack traffic lights to ease their getaways from crime scenes or pursuing police cars. </p>
<p>There are even political or financial dangers: A coordinated group could shut down several key intersections in a city and demand a ransom payment. It’s much more disruptive, and easier to get away with, than other ways of blocking intersections, like parking a car across traffic.</p>
<p>Because this type of attack exploits the smart traffic control algorithm itself, fixing it requires joint efforts from both transportation and cybersecurity fields. This includes taking into account one of the broadest lessons of our work: The sensors underlying interactive systems – such as the vehicles in the I-SIG system – aren’t inherently trustworthy. Before engaging in calculations, algorithms should attempt to validate the data they’re using. For example, a traffic-control system could use other sensors – like <a href="https://auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/question234.htm">in-road sensors</a> already in use across the nation – to double-check how many cars are really there.</p>
<p>This is just the beginning of our research into new types of security problems in the smart transportation systems of the future, which we hope will both discover weaknesses and identify ways to protect the roads and the drivers on them.</p><img src="https://counter.theconversation.com/content/95339/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Qi Alfred Chen receives funding from NSF and University of Michigan. </span></em></p><p class="fine-print"><em><span>Z. Morley Mao receives funding from NSF, ONR, and University of Michigan.</span></em></p>New research has uncovered a previously unknown weakness in smart city systems: devices that trust each other. That could lead to some pretty terrible traffic, among other problems.Alfred Chen, Assistant Professor in Computer Science, University of California, IrvineZ. Morley Mao, Professor of Electrical Engineering and Computer Science, University of MichiganLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/922582018-02-28T19:17:33Z2018-02-28T19:17:33ZGrowth pains and gridlock come to Hobart, and building more roads is not the best way out<figure><img src="https://images.theconversation.com/files/207621/original/file-20180223-108113-1l1feya.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The morning traffic builds up on the Tasman Highway at Montagu Bay. Congestion has become a hot issue for Hobart residents.</span> <span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Tasman_Highway#/media/File:Tasman-hwy-montagu-bay2.jpg">Wiki ian/Wikipedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Hobart is a city with growing pains. As Australia’s second-oldest city, it might be likened to an octogenarian suddenly experiencing a teenage “growth spurt”. Growth is occurring both in <a href="http://www.themercury.com.au/news/tasmania/the-number-of-visitors-to-southern-tasmania-over-12-months-reaches-one-million/news-story/4e03dd32e025e9735897fa2dc67be983">visitor numbers</a> and new <a href="https://profile.id.com.au/australia/population?WebID=300">residents</a>. </p>
<p>The March 3 state election has drawn attention to several growth-related issues, including <a href="http://www.abc.net.au/news/2018-02-08/tasmanias-popularity-leads-to-housing-shortage/9409460">housing affordability</a>, <a href="https://www.realestate.com.au/news/hobart-has-the-tightest-rental-vacancy-rate-in-australia/">rental vacancies</a> and <a href="http://www.abc.net.au/news/2017-07-09/hobart-peak-hour-commute-takes-30-per-cent-longer/8691680">traffic congestion</a>. These issues are not new for many Australian cities, or indeed for cities globally. But in Hobart they are almost as surprising as the city’s midwinter <a href="http://www.abc.net.au/news/2017-06-21/dark-mofo-nude-solstice-swim-towel-shortage-tasmania/8637118">2017 nude swim</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/207626/original/file-20180223-108110-1k7hv48.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/207626/original/file-20180223-108110-1k7hv48.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/207626/original/file-20180223-108110-1k7hv48.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/207626/original/file-20180223-108110-1k7hv48.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/207626/original/file-20180223-108110-1k7hv48.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/207626/original/file-20180223-108110-1k7hv48.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/207626/original/file-20180223-108110-1k7hv48.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The 2017 Dark Mofo nude swim attracted a record number of participants.</span>
<span class="attribution"><span class="source">Dark Mofo</span></span>
</figcaption>
</figure>
<h2>A highly car-dependent city</h2>
<p>While Hobart is perceived as a walkable city, it is among Australia’s most car-dependent. A <a href="http://www.transport.tas.gov.au/__data/assets/pdf_file/0003/109731/Household_Travel_Survey_Summary_-_Final.pdf">2010 survey of Hobart’s households</a> showed that 89% of people’s travel was as a car driver or passenger. </p>
<p>For some Hobart residents, being able to drive anywhere is seen as a right. This attitude was neatly summed up in a Metro Tasmania survey where one respondent <a href="https://www.busnews.com.au/industry-news/1105/tasmanians-reluctant-to-ditch-cars-survey-says">said</a>:</p>
<blockquote>
<p>Tasmanians would drive to the toilet if they could.</p>
</blockquote>
<p>But the increase in Hobart’s traffic over the past few years is no joke. The city’s morning and afternoon peak hours increasingly <a href="http://www.abc.net.au/news/2018-02-15/hobart-commuters-vent-anger-over-huge-traffic-jam/9449206">dominate the local news</a>. It’s now anyone’s guess how long the once eight-minute cross-town trip might take. </p>
<p>Residents are concerned not just about inconvenience or lost productivity. Hobart’s outlying low-density suburbs are <a href="https://theconversation.com/australian-cities-are-far-from-being-meccas-for-walking-and-cycling-87331">poorly serviced by public transport</a>. They are predominantly home to residents who are highly dependent upon their cars for work, trips for healthcare, social activities and recreation. For residents living in <a href="https://theconversation.com/australias-most-disadvantaged-suburbs-where-are-they-and-who-lives-there-13181">some of the most comparatively disadvantaged</a> suburbs in the nation, this situation is highly inequitable.</p>
<h2>Poor land use planning partly to blame</h2>
<p>While Hobart’s growth can’t compare with <a href="http://infrastructureaustralia.gov.au/policy-publications/publications/future-cities.aspx">Melbourne or Sydney</a>, the city has a <a href="https://trove.nla.gov.au/newspaper/article/26138351">long history</a> of concerns about traffic. This congestion is partly attributable to its urban form and partly to poor planning. </p>
<p>The central business district, where most jobs are located, occupies a narrow area of land wedged between steep terrain and the Derwent River. Only a few main roads carry daily commuter traffic. If one becomes blocked by, for example, a crash, this can cause traffic jams that extend to the outlying suburbs.</p>
<p>Second, the city sprawls outwards in corridors along the Derwent River and towards the international airport. Post-war suburban development is highly car-dependent; the city’s last passenger rail line was <a href="http://www.visithobartaustralia.com.au/lost-railways.html">closed in 1978</a>. </p>
<p>Transport has become a hot-button issue for ordinary residents and politicians alike in this state election campaign. But planning responses thus far have been piecemeal and superficial, such as moving a few car parks and synchronising traffic lights.</p>
<p>Some <a href="http://www.themercury.com.au/news/politics/hodgman-pledges-fourlane-highway-from-hobart-to-sorell/news-story/643b07809bcdd97f39a515987cd8b3ba">election promises</a> are “throwbacks” to the road-building ideology of the 1950s. More lanes ultimately lead to more congestion. International experiences from cities like Los Angeles show that adding more lanes to roads only creates congestion. </p>
<p>Other proposals accord with modern city planning and represent quite a radical <a href="http://www.abc.net.au/news/2018-02-01/liberal-party-release-bold-vision-for-hobart-transport/9383114">step up in transport planning</a> for Hobart. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sidelining-planners-makes-for-poorer-urban-policy-and-future-generations-will-pay-the-price-73186">Sidelining planners makes for poorer urban policy, and future generations will pay the price</a>
</strong>
</em>
</p>
<hr>
<h2>Key steps to fix the transport system</h2>
<p>Solutions to fix Hobart’s transport problems are necessarily medium to long term. To succeed, these should follow several transport planning principles:</p>
<ul>
<li><p><strong>Prioritise the movement of people.</strong> This means removing private car parking in favour of pedestrian malls and reusing some road lanes as dedicated bus lanes. Reducing the width of some road lanes can also accommodate more pedestrians and cyclists. </p></li>
<li><p><strong>Integrate transport and land use planning.</strong> This means creating new suburban and infill housing near existing public transit services. Planning schemes should allow medium density and mixed use development in appropriate places, to encourage walking and transit use. It should be possible to use public transport to make daily trips for education, shopping, entertainment, healthcare and the like.</p></li>
<li><p><strong>Price road space appropriately.</strong> This might occur by adopting Victoria’s <a href="https://www.vicroads.vic.gov.au/traffic-and-road-use/traffic-management/smartroads">SmartRoads</a> system. SmartRoads manages competing interests for limited road space by deciding which modes have priority on which roads. It recognises the increasing importance of public transport, walking and cycling. <a href="https://theconversation.com/city-wide-trial-shows-how-road-use-charges-can-reduce-traffic-jams-86324">Congestion pricing</a> in London, Stockholm and Singapore follows this principle.</p></li>
<li><p><strong>Create a multi–mode public transport system.</strong> Light rail, buses and ferries should <a href="https://theconversation.com/getting-public-transport-right-means-less-emphasis-on-rail-45">all play a role</a> in moving people around Hobart. The ticketing system should be integrated and allow free transfers between modes.</p></li>
<li><p><strong>Reduce the demand.</strong> Some employment functions could be moved out of the CBD to suburban sites. And road users might be able to <a href="https://www.hobartcity.com.au/Council/Strategies-and-plans/City-of-Hobart-Employee-Travel-Plan">stagger use</a>, by starting work at different times, choosing different routes and <a href="https://theconversation.com/stuck-in-traffic-maths-can-get-you-on-your-way-15125">car-pooling</a>.</p></li>
</ul>
<p>To fix Hobart’s traffic congestion woes these proven principles need to be followed. Reasons for doing this include reducing carbon emissions, health imperatives and economic efficiency. </p>
<p>With five major councils in the Greater Hobart area and a <a href="http://stca.tas.gov.au/">Southern Tasmanian Councils Authority</a> that has no funding or staff, the state government needs to step in and co-ordinate a range of actions. There is no better time to start than with a freshly elected government on March 4.</p><img src="https://counter.theconversation.com/content/92258/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emma Pharo is a current member of the Road Safety Advisory Council and has consulted for the Department of State Growth on pedestrian safety and amenity. She was a public relations advisor for Bicycle Network between 2011 and 2016 and is a current member of the Hobart Bike Advisory Committee. Emma is a member of the Planning Institute of Australia's policy sub-committee in Tasmania.</span></em></p><p class="fine-print"><em><span>Jason Byrne receives funding from the Australian Research Council for research on (i) climate change and social innovation and (ii) green space and health. He is a member of the Planning Institute Australia, Institute of Australian Geographers and Association of American Geographers. Jason donates to environmental groups (e.g. Australian Conservation Foundation) and has presented at the Green Institute conference. He provides research consultancy services to local government (e.g. City of Gold Coast).</span></em></p>Hobart is a smaller city with big city problems that have become an election issue. Recent growth is creating traffic congestion that affects productivity, residents’ health and liveability.Emma Pharo, Senior Lecturer, Geography and Environmental Studies, University of TasmaniaJason Byrne, Professor of Human Geography and Planning, University of TasmaniaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/908142018-02-07T11:28:50Z2018-02-07T11:28:50ZAre traffic-clogged US cities ready for congestion pricing?<figure><img src="https://images.theconversation.com/files/204939/original/file-20180205-14104-blb0r4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Times Square traffic jam.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/cmJa3q">bk</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>New York is the latest city to contemplate <a href="https://www.nytimes.com/2018/01/18/nyregion/driving-manhattan-congestion-traffic.html">congestion pricing</a> as a way to deal with traffic problems. This strategy, which requires motorists to pay fees for driving into city centers during busy periods, is a rarity in urban public policy: a measure that works and is cost-effective. </p>
<p>Properly used, congestion pricing can ease traffic, speed up travel times, reduce pollution and provide funds for public transport and infrastructure investments. The details matter, including the size and timing of charges and the area that they cover. Congestion charges also raises equity issues, since rich people are best able to move closer to work or change their schedules to avoid the steepest costs. </p>
<p>But the key point is that this approach has succeeded in cities including London, Singapore and Stockholm. For scholars like me who focus on urban issues, serious discussion of congestion pricing in New York City is welcome news. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/204942/original/file-20180205-14089-kzh7bc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/204942/original/file-20180205-14089-kzh7bc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/204942/original/file-20180205-14089-kzh7bc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=351&fit=crop&dpr=1 600w, https://images.theconversation.com/files/204942/original/file-20180205-14089-kzh7bc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=351&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/204942/original/file-20180205-14089-kzh7bc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=351&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/204942/original/file-20180205-14089-kzh7bc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=441&fit=crop&dpr=1 754w, https://images.theconversation.com/files/204942/original/file-20180205-14089-kzh7bc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=441&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/204942/original/file-20180205-14089-kzh7bc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=441&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Commuters crowd a Grand Central subway station platform in New York, May 4, 2016. Proposed congestion charges in New York would generate money to improve public transit.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Stuck-in-the-Subway/5289431d677b4c16971d7f8c770ca9e1/72/0">AP Photo/Bebeto Matthews, File</a></span>
</figcaption>
</figure>
<h2>The down side of density</h2>
<p>Cities concentrate people close together for good economic reasons. Clustering activities allows transfers of information, knowledge and skills. At their best, cities create deep pools of labor, large markets of consumers and savings in the provision of public goods such as mass transit and trash collection. Planners should be encouraging cities to <a href="https://theconversation.com/want-the-economy-to-grow-its-time-to-look-at-cities-and-efficiency-54517">become bigger and more dense</a> if we want to improve economic performance.</p>
<p>But growing concentration also imposes costs, and one of the largest is traffic congestion. Costs multiply when we factor in use of motor vehicles on public roads. Drivers spend valuable time sitting idly in traffic jams, while noise, accidents and pollution impose heavy burdens on city residents. </p>
<h2>Should road use be free?</h2>
<p>The idea of charging for use of public roads is not new. Economist Arthur Pigou discussed the issue <a href="https://www.amazon.com/Economics-Welfare-Classics-Economics/dp/0765807394/ref=sr_1_4?s=books&ie=UTF8&qid=1517221260&sr=1-4&keywords=Arthur+Pigou">as early as 1920</a> as part of his attempt to remedy the suboptimal workings of the market system. In 1963 Canadian-born economist William Vickrey argued that roads were scarce resources that should be valued by <a href="http://www.jstor.org/stable/1823886?seq=1#page_scan_tab_contents">imposing costs on users</a>. </p>
<p>Consumers intuitively understand differential pricing. We expect to pay more for airline tickets at peak travel times and for hotel rooms at popular times of the year. Congestion pricing operates in the same way. By increasing prices, it forces users to think about the cost of making a trip. A congestion tax is what behavioral economists call a <a href="https://books.google.com/books?hl=en&lr=&id=89BpAwAAQBAJ&oi=fnd&pg=PA1&dq=Nudge&ots=Bw5AHbgBoT&sig=j_P3h_JdqZ85Mx_4QInz3JWB18g#v=onepage&q=Nudge&f=false">“nudge”</a> that makes people evaluate their travel patterns.</p>
<p>And it can be effective. A 2008 <a href="https://www.seattletimes.com/seattle-news/wide-use-of-tolls-could-unclog-roads-seattle-study-says/">study</a> gave drivers in Seattle a hypothetical cash sum to spend on trips, charged them tolls linked to traffic congestion levels, and let them keep money they did not spend. Their cars were fitted with equipment to monitor driving patterns. </p>
<p>The results showed that pricing affected behavior: Travelers altered their schedules, took different routes or collapsed multiple trips into single journeys. Collectively, these changes reduced congestion at peak time, lessened wait times and increased average travel speeds in the study’s regional traffic model.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/204943/original/file-20180205-14096-r8448g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/204943/original/file-20180205-14096-r8448g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/204943/original/file-20180205-14096-r8448g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=368&fit=crop&dpr=1 600w, https://images.theconversation.com/files/204943/original/file-20180205-14096-r8448g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=368&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/204943/original/file-20180205-14096-r8448g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=368&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/204943/original/file-20180205-14096-r8448g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=462&fit=crop&dpr=1 754w, https://images.theconversation.com/files/204943/original/file-20180205-14096-r8448g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=462&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/204943/original/file-20180205-14096-r8448g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=462&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Travel speeds across Manhattan and citywide have consistently fallen since 2012.</span>
<span class="attribution"><a class="source" href="http://www.nyc.gov/html/dot/html/about/mobilityreport.shtml">New York City DOT</a></span>
</figcaption>
</figure>
<h2>Congestion pricing in practice</h2>
<p><a href="https://ops.fhwa.dot.gov/publications/fhwahop08047/02summ.htm">Singapore</a> was one of the first major cities to introduce congestion pricing in 1975, charging US$1.30 for a vehicle to enter the central business district between 7:30 and 9:30 a.m. The policy had political support because most residents used public transport, with only the wealthiest driving private cars. The tax was viewed as a more equitable distribution of costs.</p>
<p>The net result was that congestion was reduced and travel times improved. Between 1975 and 1988, the project generated revenues 11 times larger than its costs. Pollution decreased and pedestrian safety improved. In 1998 Singapore shifted to <a href="http://roadpricing.blogspot.com/2016/03/singapore-will-have-worlds-first-gnss.html">variable charges</a> that target congested road stretches and vary by time of day and travel direction.</p>
<p><a href="https://ops.fhwa.dot.gov/publications/fhwahop08047/02summ.htm">London</a> introduced congestion pricing in 2003, charging motorists, entering central London between 7 a.m. and 6 p.m. on weekdays, 5 British pounds (about $7) per day. The scheme generated 2.6 billion pounds (about $3.63 billion) in its first decade, almost half of which was invested in public transport and infrastructure improvements. </p>
<p>The Congestion Charge, as it is known, reduced the number of automobiles entering the city by <a href="https://www.centreforpublicimpact.org/case-study/demand-management-for-roads-in-london/">44 percent</a> from the pre-charge level and slightly reduced traffic accidents. Air quality in central London also improved. </p>
<p>The charge did produce some <a href="http://www.ires.nus.edu.sg/workingpapers/IRES2016-013.pdf">unintended consequences</a>. House prices within the Congestion Charge zone increased – bid upward by consumers who appear willing to pay to avoid traffic and enjoy improved environmental conditions. Over the long term, the congestion tax lubricated the gentrification of central London. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/204945/original/file-20180205-14064-l53kcc.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/204945/original/file-20180205-14064-l53kcc.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/204945/original/file-20180205-14064-l53kcc.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=431&fit=crop&dpr=1 600w, https://images.theconversation.com/files/204945/original/file-20180205-14064-l53kcc.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=431&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/204945/original/file-20180205-14064-l53kcc.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=431&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/204945/original/file-20180205-14064-l53kcc.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=542&fit=crop&dpr=1 754w, https://images.theconversation.com/files/204945/original/file-20180205-14064-l53kcc.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=542&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/204945/original/file-20180205-14064-l53kcc.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=542&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">London’s Congestion Charge zone.</span>
<span class="attribution"><a class="source" href="https://tfl.gov.uk/modes/driving/congestion-charge/congestion-charge-zone">Transport for London</a></span>
</figcaption>
</figure>
<p>But this process is common to many other big cities, with or without congestion pricing: The rich preempt central city locations and <a href="https://www.amazon.com/Unequal-City-Resurgence-Displacement-Inequality/dp/1138280372/ref=asap_bc?ie=UTF8">displace the less wealthy to the suburbs</a>. </p>
<p><a href="https://ops.fhwa.dot.gov/publications/fhwahop08047/02summ.htm">Stockholm</a> introduced a congestion tax in 2007, after a seven-month trial and bitter political fights. Vehicles entering the central city were charged different rates over the course of the day, reaching 35 Swedish kronor (about $4.40) during morning and evening rush hours. </p>
<p>The tax gradually gained public support and decreased congestion as commuters <a href="http://www.transportportal.se/swopec/cts2014-7.pdf">shifted to public transport</a>.
Other Swedish municipalities have since copied the scheme.</p>
<h2>Congestion pricing in the US</h2>
<p>While the United States has <a href="https://www.ibtta.org/sites/default/files/documents/MAF/2014_TollingBrief_0.pdf">over 5,000 miles of toll roads</a>, congestion pricing is uncommon. One exception is Interstate Route 66 in the Washington, D.C., metro region, where <a href="https://www.marketwatch.com/story/a-40-toll-for-a-10-mile-trip-this-is-the-new-infrastructure-math-2017-12-07">fluctuating tolls</a> were introduced on Dec. 4, 2017. Pricing for these express lanes changes every six minutes during rush hour eastbound in the morning and westbound in the afternoon. The toll hit $40 for a 10-mile stretch the day after it was introduced. </p>
<p>But this is just one well-used road, and there are many other routes into central Washington. The I-66 tolls are more about generating revenue on one road than reducing congestion citywide. </p>
<p>Currently, the <a href="http://www.hntb.com/HNTB/media/HNTBMediaLibrary/Home/Fix-NYC-Panel-Report.pdf">proposed plan</a> for New York City would charge cars $11.52 cars to enter Manhattan below 60th Street on weekdays during business hours. Trucks would be charged $25.34, and taxis and app-based rides such as Uber and Lyft would be charged $2 to $5. The tax would generate $1.5 billion yearly.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/204941/original/file-20180205-14072-17xzi95.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/204941/original/file-20180205-14072-17xzi95.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/204941/original/file-20180205-14072-17xzi95.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=197&fit=crop&dpr=1 600w, https://images.theconversation.com/files/204941/original/file-20180205-14072-17xzi95.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=197&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/204941/original/file-20180205-14072-17xzi95.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=197&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/204941/original/file-20180205-14072-17xzi95.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=248&fit=crop&dpr=1 754w, https://images.theconversation.com/files/204941/original/file-20180205-14072-17xzi95.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=248&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/204941/original/file-20180205-14072-17xzi95.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=248&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Proposed zone pricing for Manhattan Central Business District.</span>
<span class="attribution"><a class="source" href="http://www.hntb.com/HNTB/media/HNTBMediaLibrary/Home/Fix-NYC-Panel-Report.pdf">Fix NYC Advisory Panel Report</a></span>
</figcaption>
</figure>
<p>What about equity? Only 4 percent of people who commute into New York City travel by car, and of those, only 5,000 could be classified as <a href="http://fortune.com/2018/01/25/nyc-congestion-fees/">working poor</a>. Increased funding from congestion fees would allow more investment in mass transit, making life easier for the majority of New Yorkers who commute by public transit. </p>
<p>Unlike other taxes that can be easily dismissed as imposing costs and killing jobs, congestion pricing improves market efficiencies because it forces people to think about their travel and leads to a more rational use of our public roads. In my view, it is a powerful policy whose time has definitely come.</p><img src="https://counter.theconversation.com/content/90814/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Rennie Short does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>New York soon may charge a fee to drive into central Manhattan as a way of reducing traffic and raising funds for public transit. An urban scholar says this step is overdue in the United States.John Rennie Short, Professor, School of Public Policy, University of Maryland, Baltimore CountyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/879312017-11-26T19:09:47Z2017-11-26T19:09:47ZDelay in changing direction on how we tax drivers will cost us all<figure><img src="https://images.theconversation.com/files/195996/original/file-20171123-6035-xkovik.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Reforming how drivers pay for the costs of their road use can help keep traffic flowing, which is just one of the potential benefits. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sydney-city-skyline-443951992?src=AHSkJxZz-VZiOF2EsBjT1g-1-0">Holli/Shutterstock</a></span></figcaption></figure><p>The federal government <a href="https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwiY_OyQ4tXXAhWKn5QKHTazCMEQFggmMAA&url=http%3A%2F%2Fwww.afr.com%2Fnews%2Fplan-to-replace-fuel-tax-with-user-charges-20161123-gsw85c&usg=AOvVaw1mV6sYjoHwABOI4_ehGc25">announced</a> a year ago that it would review the charges imposed on drivers for using our roads. That review hasn’t yet happened. They should get on with it, because reforming the way we charge road users will make our economy more productive and our cities more liveable. The longer we wait, the harder the path to those improvements becomes.</p>
<p>The problem with the present system is that there is only a weak link between what motorists pay and the costs they create when they use roads. The amount motorists pay for registration, for example, does not vary with the amount of time they spend on the road, let alone how long they’re stuck in traffic jams.</p>
<hr>
<p><em><strong>Further reading:</strong> <a href="https://theconversation.com/road-user-charging-belongs-on-the-political-agenda-as-the-best-answer-for-congestion-management-65027">Road user charging belongs on the political agenda as the best answer for congestion management</a></em></p>
<hr>
<p>But before we get to the benefits of reforming how drivers pay for the costs of their road use, we need to debunk a big myth about road funding in Australia. It’s one that has become a major distraction in discussions about the need for change.</p>
<h2>The myth of the fuel excise crisis</h2>
<p>Vehicle technology is improving. Cars are becoming more fuel-efficient, and powering them with electricity is becoming more mainstream. At the same time, our commuting patterns are changing – over the past few years, the average distance Australians travel by car <a href="http://www.abs.gov.au/AUSSTATS/abs@.nsf/Lookup/9208.0Main+Features112%20months%20ended%2030%20June%202016?OpenDocumenthttp://www.abs.gov.au/AUSSTATS/abs@.nsf/Lookup/9208.0Main+Features112%20months%20ended%2030%20June%202016?OpenDocument">has fallen</a>.</p>
<p>This is worrying the government, which collects fuel excise from us every time we fill the car with petrol. Urban Infrastructure Minister Paul Fletcher has <a href="http://minister.infrastructure.gov.au/pf/speeches/2017/pfs015_2017.aspx">specifically raised concerns</a> that: </p>
<blockquote>
<p>…the revenue from fuel excise and car registration is unlikely to keep pace with the amount we spend as a nation on operating, maintaining and investing in roads.</p>
</blockquote>
<p>The government’s key economic advisory body, the Productivity Commission, <a href="https://www.pc.gov.au/inquiries/completed/productivity-review/report/productivity-review-supporting9.pdf">recently suggested</a> reform of the fuel excise levy was “becoming more urgent”. But talk of a funding crisis is overblown.</p>
<p>First, the minister knows that the government doesn’t, and can’t, segregate revenue from road use to spend on roads. Federal spending on infrastructure is funded from general government revenue, the pool of funds received from the full range of federal taxes. As far as the government is concerned, road funding is just one of many expense programs claiming a piece of the budget pie.</p>
<p>As for revenue from the fuel excise, the decision in 2014 to <a href="https://www.aph.gov.au/About_Parliament/Parliamentary_Departments/Parliamentary_Library/pubs/rp/BudgetReview201415/FuelExcise">reintroduce indexation</a> will deliver much-needed relief for the government. The truth is, revenue did not fall much over the past decade and the levy now increases each year in line with inflation. The government may cry poor, but it can’t cry broke.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/196051/original/file-20171123-6013-158o9e3.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/196051/original/file-20171123-6013-158o9e3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/196051/original/file-20171123-6013-158o9e3.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/196051/original/file-20171123-6013-158o9e3.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/196051/original/file-20171123-6013-158o9e3.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/196051/original/file-20171123-6013-158o9e3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/196051/original/file-20171123-6013-158o9e3.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/196051/original/file-20171123-6013-158o9e3.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<h2>So, do we still need that long-promised review?</h2>
<p>Fuel excise revenue is not the problem the government would have you think it is. But its promised review remains important because reforming road-user charges would bring big benefits for Australia.</p>
<p>The disconnect between what motorists pay and the costs of their road use matters because traffic congestion is the main cost that cars create when they use existing roads. The regular wear and tear of our roads is overwhelmingly caused by trucks and other heavy vehicles; cars do negligible damage to paved roads. </p>
<p>An <a href="https://www.ntc.gov.au/heavy-vehicles/heavy-vehicle-charges/">existing mechanism</a> ensures that trucks are charged for their wear and tear on roads. What’s needed is an equivalent mechanism to ensure that cars are charged for the costs they create by adding to congestion.</p>
<p>As we describe in our report <a href="https://grattan.edu.au/report/stuck-in-traffic/">Stuck in traffic? Road congestion in Sydney and Melbourne</a>, such a mechanism would mean charging people who drive at peak times on congested roads a small fee.</p>
<hr>
<p><em><strong>Further reading:</strong> <a href="https://theconversation.com/stuck-in-traffic-we-need-a-smarter-approach-to-congestion-than-building-more-roads-84774">Stuck in traffic: we need a smarter approach to congestion than building more roads</a></em></p>
<hr>
<p>People who pay the charge would get a quicker and more reliable trip, because there would be fewer cars on the road at peak times. People who can travel outside of the peaks would not have to pay, because there would be no congestion charge when the roads are not congested. Because traffic flows would be spread more evenly across all hours of the day, our economy would become more efficient and our cities more liveable.</p>
<p>Critics of these decongestion schemes argue that charging motorists in this way is unfair. Why should low-income earners or those living on the fringes of our major cities, they argue, be hit with a new charge for something they can’t avoid when they go to work?</p>
<p>It’s a valid concern, but our report suggests it is entirely feasible to redesign motor vehicle charges in ways that actually make them fairer. </p>
<p>A key element of fairness is that any new congestion charge should be offset by reducing or removing vehicle registration charges. The goal should be to change how we pay for roads, not how much we pay. Developing such options is precisely what the long-promised review should do.</p>
<p>This reform would allow us to get the greatest value from the road network we already have, before we ask taxpayers and motorists to pay for constructing big and expensive new roads.</p>
<h2>Time to get the show on the road</h2>
<p>If we don’t make changes, congestion and delays on the roads in our biggest cities will only get worse. The government should provide terms of reference for the review before Christmas. These terms should acknowledge the importance of developing options for charging motorists for the congestion they cause. </p>
<p>In doing so, it will be important to resolve how the range of state-levied taxes on motorists, <a href="https://theconversation.com/city-wide-trial-shows-how-road-use-charges-can-reduce-traffic-jams-86324">including existing and prospective toll roads</a>, might fit within new charging arrangements. Only then should the review turn to the question of how many expensive new roads the states should be building.</p><img src="https://counter.theconversation.com/content/87931/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Grattan Institute began with contributions to its endowment of $15 million from each of the Federal and Victorian Governments. In order to safeguard its independence, Grattan Institute’s board controls this endowment. The funds are invested and Grattan uses the income to pursue its activities.
</span></em></p><p class="fine-print"><em><span>Hugh Batrouney does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Traffic congestion is the main cost that cars create when they use existing roads. Road use charges are a more efficient and fairer way to cover the cost and help ensure traffic flows.Marion Terrill, Transport Program Director, Grattan InstituteHugh Batrouney, Transport Fellow, Grattan InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/863242017-11-22T19:09:54Z2017-11-22T19:09:54ZCity-wide trial shows how road use charges can reduce traffic jams<figure><img src="https://images.theconversation.com/files/195316/original/file-20171119-11450-mgpqvz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A trial of 1,400 drivers across Melbourne suggests time-of-use charges can be effective in easing traffic congestion.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/rush-hour-queues-beginning-form-on-580546471?src=KiE-2csfy8a_FCdJm_OoGg-1-18">AMPG/Shutterstock</a></span></figcaption></figure><p>Road congestion in large Australian cities is estimated to cost <a href="https://bitre.gov.au/publications/2015/is_074.aspx">more than A$16 billion a year</a>. Economists have <a href="http://www.vtpi.org/vickrey.htm">long argued</a> the best way to improve traffic flow is to charge drivers for their contribution to road congestion. We have now analysed data collected from 1,400 drivers across Melbourne to see whether road user charging can change their behaviour in ways that ease congestion. And the answer is yes.</p>
<p>Because the obstacle to adopting this approach has been concern about its fairness, we also looked at driver incomes. Would congestion-based charges price the poor off the road for the benefit of those who can pay? We calculated how different systems of road use charges affected households on different incomes, and how driving patterns changed under different prices.</p>
<p>The evidence does not support other common policy responses to traffic congestion. Building new roads <a href="https://www.aeaweb.org/articles?id=10.1257/aer.101.6.2616">does little to relieve congestion</a>. Placing tolls on roads can push traffic onto others. </p>
<hr>
<p><em><strong>Further reading:</strong> <a href="https://theconversation.com/do-more-roads-really-mean-less-congestion-for-commuters-39508">Do more roads really mean less congestion for commuters?</a></em></p>
<hr>
<p>However, even small reductions in congestion can produce large benefits. On congested roads, reducing traffic by 5% can increase traffic speeds <a href="https://sitwww.mynrma.com.au/media/NRMA_Decongestion_Strategy.pdf">by up to 50%</a>. </p>
<p>The question is: what would the optimal charges be? Drivers often plan their travel ahead of time, so <a href="https://help.uber.com/h/e9375d5e-917b-4bc5-8142-23b89a440eec">Uber-like surge pricing</a> is not necessarily the best way to go. Could simpler fixed charges, based perhaps on time of day or location, be effective?</p>
<p>In 2015-2016, Transurban Group implemented the <a href="https://changedconditionsahead.com/">Melbourne Road Usage Study</a> (MRUS) to answer these questions. More than 1,400 drivers across greater Melbourne installed GPS devices in their vehicles for eight to ten months. After a period to establish baseline use, a randomly selected subset faced a series of road use charges via a system of virtual accounts. Every month participants accumulated real money from reduced charges as a result of their decisions about driving.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/194284/original/file-20171113-27616-ca2bn1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/194284/original/file-20171113-27616-ca2bn1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/194284/original/file-20171113-27616-ca2bn1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/194284/original/file-20171113-27616-ca2bn1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/194284/original/file-20171113-27616-ca2bn1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/194284/original/file-20171113-27616-ca2bn1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/194284/original/file-20171113-27616-ca2bn1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/194284/original/file-20171113-27616-ca2bn1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A congestion-charging zone in central London.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/congestion-charge-zone-sign-introduced-2003-722719189">Bikeworldtravel/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Well-targeted charges ease congestion</h2>
<p>The Melbourne Road Usage Study tested three simple charges:</p>
<ul>
<li>a flat distance-based charge of 10 cents per kilometre</li>
<li>a time-of-day charge of 15 cents per kilometre at peak times and 8 cents at other times</li>
<li>a distance-plus-cordon charge where drivers were charged 8 cents per kilometre at all times plus A$8 if they entered the inner city.</li>
</ul>
<p>Our working paper, <a href="https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3055522">Can Road Charges Alleviate Congestion?</a>, evaluates the raw data. </p>
<p>Charges that vary by time of day were most effective at reducing driving at congested times. Drivers subjected to a higher cost of driving in the weekday peak hours of 7am to 9am and 3pm to 6pm reduced travel by 10% during these periods.</p>
<p>While a simple 10 cent charge on distance travelled did reduce driving, this was mainly outside the congested inner city and at off-peak times – mostly in the middle of the day and on weekday evenings. Most freeway congestion occurs around morning and late afternoon commutes. </p>
<p><a href="https://tfl.gov.uk/modes/driving/congestion-charge">London</a> and <a href="https://www.lta.gov.sg/content/ltaweb/en/roads-and-motoring/managing-traffic-and-congestion/electronic-road-pricing-erp.html">Singapore</a> have charges to enter the congested city centre. Further research is needed to assess the effects on inner-city traffic in Australian cities. </p>
<p>The evidence points towards most drivers who enter the CBD being willing to pay higher weekday charges. But few drivers entered the cordon zone during the study. Less than 5% of the drivers made over half of the trips into the area.</p>
<h2>Access to reliable public transport matters</h2>
<p>Public transit has a key role in getting cars off the road. Our data showed households located far from the CBD and from public transport drive more. Living 500 metres closer to a tram or train station has the same effect on kilometres driven each day as living 5km closer to the CBD. </p>
<p>Households within a 10-minute walk from public transport drive least. The largest reductions in driving from time-of-day and cordon charges come from households living 10 to 20 minutes’ walk away. </p>
<h2>Road use charges could be fairer</h2>
<p>Congestion-based charges can be a more progressive way to fund roads than the existing system of registration fees and fuel taxes. </p>
<p>The fuel excise makes up <a href="http://www.infrastructurevictoria.com.au/sites/default/files/images/The%20road%20ahead%20final%20web.pdf">almost half of the average annual road bill in Australia</a>. It’s essentially a distance-based fee, but more fuel-efficient vehicles pay less per kilometre travelled. Hybrid vehicle drivers, for example, contribute much less to fuel tax revenue. </p>
<p>Yet, although hybrids contribute less to air pollution, they increase congestion just as much as their petrol-guzzling counterparts. And congestion <a href="https://www.aeaweb.org/articles?id=10.1257/0002828054825510">is a much greater shared economic cost</a> than vehicle air pollution.</p>
<p>Annual vehicle registration fees make up most of the remaining road bill. These provide no incentive to reduce congestion. </p>
<p>Fuel taxes and registration fees put a disproportionate burden on low-income households in the outer suburbs. Our research shows these households would be better off if roads were funded more by congestion charges.</p>
<h2>Field experiments help get the settings right</h2>
<p>So what is the optimal congestion charge? Economic theory (<a href="http://www.econlib.org/library/NPDBooks/Pigou/pgEWCover.html">Pigou 1920</a>) tells us to price at the cost that each extra user imposes on the system. </p>
<p>With road use, though, the calculation is difficult. To fix rates in advance, we would need to know exactly how much longer everyone’s trip is when each extra driver joins each system. And we’d need to cost that slowdown for each individual on the road at that time (i.e. value their time and, potentially, the cost to them of being late). <a href="http://economics.mit.edu/files/13619">New research</a> has been using clever experimental designs to identify these values.</p>
<p>That said, maybe it is not too important to get the price just right. For electricity, we are <a href="http://jamesgillan.info/s/JMP_Gillan_most_recent_draft.pdf">starting to see</a> that households respond to there being a price, not its specific level. </p>
<p>Before widespread road use charges are implemented, we would like to see more field experiments like the MRUS to find answers to other questions. Would it be better to combine a time-of-day charge with targeted locations? How effective would it be to charge more for using highly congested arterial roads at peak times? Would this simply push congestion onto nearby local roads? How large a gap between peak and off-peak prices is needed to produce a strong response?</p>
<p>Another interesting option is the <a href="https://www.arec.umd.edu/sites/arec.umd.edu/files/_docs/events/Antonio%20Bento-Avoiding%20Traffic%20Congestion%20Externalities.pdf">i10 model</a> outside Los Angeles. Two lanes are for traffic willing to pay more to get to their destination faster. </p>
<p>Dynamic pricing ensures traffic in these lanes flows freely – if too many use these lanes and traffic slows, the price increases. Drivers can decide every few kilometres if they want to pay more to stay in the express lanes. Those who must get somewhere on time are able to, and the fee revenue can be used to reduce road costs for others.</p>
<p>The Melbourne Road Usage Study (MRUS) shows field experiments can help us design better road use charges. By all appearances, households took it seriously and <a href="https://changedconditionsahead.com/">were positive about their involvement</a>. </p>
<p>The MRUS provides evidence that well-designed road use charges could help reduce congestion by encouraging people to drive at different times, take other routes or use other transport. This could lead to better use of existing infrastructure, thereby reducing costs, while generating revenue for infrastructure investments. Under such a system, drivers who contribute little to congestion could see substantial gains.</p><img src="https://counter.theconversation.com/content/86324/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Leslie A. Martin has received partial funding for this project from independent advisory body Infrastructure Victoria. In the past she has consulted for the Victorian Department of Environment, Land, Water and Planning and received funding for other projects from the Australian Research Council and the Faculty of Business and Economics at the University of Melbourne. She has not received any funding from any of the organizations involved in implementing the Melbourne Road Usage Study.</span></em></p><p class="fine-print"><em><span>Sam Thornton has received partial funding for this project from independent advisory body Infrastructure Victoria. He is also the recipient of a Commonwealth Supported Place for the Master of Economics at the University of Melbourne.</span></em></p>A city-wide experiment suggests well-designed road use charges could ease congestion by encouraging people to drive at different times, take other routes or use other transport.Leslie A. Martin, Lecturer (Assistant Professor) in Economics, The University of MelbourneSam Thornton, Research assistant, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/841782017-10-03T10:11:35Z2017-10-03T10:11:35ZGovernments, car companies must resolve their competing goals for self-driving cars<figure><img src="https://images.theconversation.com/files/186422/original/file-20170918-8300-eu875i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">When will cars be able to talk to their surroundings?</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/self-driving-electronic-computer-car-on-559597045">posteriori/Shutterstock.com</a></span></figcaption></figure><p>What self-driving cars want, and what people want from them, varies widely. And often these desires are at odds with each other. For instance, carmakers – and the designers of the software that will run autonomous vehicles – know that it’s safest if cars stay far away from each other. But traffic engineers know that if every car operated to ensure lots of surrounding space, local roads and highways alike would be clogged for miles, and nobody would get anywhere.</p>
<p>Another inherent conflict involves how cars handle crises. No consumer wants to buy a self-driving car that’s programmed, even in the most remote of circumstances, <a href="http://dx.doi.org/10.1126/science.aaf2654">to kill its driver</a> instead of someone else (even if it would <a href="http://moralmachine.mit.edu/">save a class of kindergarteners</a> or a group of Nobel Prize winners). However, if every car is programmed always to save its occupants at any cost, <a href="https://www.wired.com/2016/06/self-driving-cars-will-power-kill-wont-conscience/">pedestrians and cyclists</a> are at risk. </p>
<p>As federal regulations for self-driving cars advance in <a href="http://www.post-gazette.com/business/tech-news/2017/09/06/The-SELF-DRIVE-Act-just-passed-the-U-S-House-here-s-what-that-means-for-autonomous-vehicles/stories/201709060138">congressional votes</a> and the <a href="https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/documents/13069a-ads2.0_090617_v9a_tag.pdf">U.S. Department of Transportation issues guidelines</a>, an important part of real progress will be how everyone involved approaches those inherent conflicts. Research at the <a href="http://www.transportation.institute.ufl.edu/">University of Florida Transportation Institute</a>, where I serve as the director, shows that the key to resolving these competitions of goals is communication among all the elements of the transportation network – cars, pedestrians, bicycles, guardrails, traffic lights, stop signs, roadways themselves and everything else. And if they’re all going to talk to each other, the people who make all those things need to talk to each other too. </p>
<p>Our institute is providing opportunities to do that. Our efforts include working with the Florida Department of Transportation and the City of Gainesville to <a href="https://www.demandstar.com/supplier/bids/Bid_Detail.asp?_PU=%2Fsupplier%2Fbids%2Fagency_inc%2Fbid_list%2Easp%3F_RF%3D1%26f%3Dsearch%26mi%3D10071&LP=BB&BI=331953">set up an autonomous shuttle</a> between the UF campus and downtown Gainesville and partnering with industry to create a <a href="http://www.transportation.institute.ufl.edu/research-2/istreet/">testing area for autonomous cars and other advanced transportation technologies</a> on campus roads and surrounding highways. But with so little coordination in today’s transportation world, there’s a long way to go.</p>
<h2>Problems large and small</h2>
<p>The road system in the U.S. has serious problems. Americans spend <a href="http://www.reuters.com/article/us-usa-traffic-study/u-s-commuters-spend-about-42-hours-a-year-stuck-in-traffic-jams-idUSKCN0QV0A820150826">more than 40 hours per year</a> stuck in traffic; <a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/812412">more than 30,000 people die</a> each year in crashes on U.S. roads, making cars <a href="http://www.worldlifeexpectancy.com/usa-cause-of-death-by-age-and-gender">one of the leading causes of death</a> for Americans under the age of 64. These are serious problems, and <a href="http://www.automatedvehiclessymposium.org/home">many hope</a> that autonomous cars can help solve them.</p>
<p>Nationwide statistics can mask smaller issues, though. The country’s transportation system is full of examples where coordination and collaboration would be extremely helpful., and even where the individual components may work but the system overall isn’t as streamlined as it could be.</p>
<p>Many communities have major roads where <a href="http://www.twincities.com/2017/09/09/minnesota-36-commuters-to-get-20-more-seconds-of-green-and-whos-using-new-st-croix-bridge/">drivers have to stop unnecessarily</a> because <a href="http://news.mit.edu/2014/traffic-lights-theres-a-better-way-0707">traffic lights aren’t coordinated</a> among the different towns drivers pass through. And because different government agencies operate highways and local roads, when emergencies happen, drivers aren’t always <a href="https://waldo.villagesoup.com/p/officials-debrief-aug-2-traffic-nightmare/1684341">rerouted smoothly</a> or efficiently.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/186421/original/file-20170918-8236-4rojqf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/186421/original/file-20170918-8236-4rojqf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/186421/original/file-20170918-8236-4rojqf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/186421/original/file-20170918-8236-4rojqf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/186421/original/file-20170918-8236-4rojqf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/186421/original/file-20170918-8236-4rojqf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/186421/original/file-20170918-8236-4rojqf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/186421/original/file-20170918-8236-4rojqf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The city of Atlanta is one of many communities – including Gainesville, Florida – exploring the technology and effects of self-driving cars.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Self-Driving-Cars/22319764d6d64e0286906b6d4eef15f2/2/0">AP Photo/Johnny Clark</a></span>
</figcaption>
</figure>
<h2>Making a place for testing</h2>
<p>With the Florida Department of Transportation and the city of Gainesville, our institute is building what we’re calling <a href="http://www.transportation.institute.ufl.edu/research-2/istreet/">I-STREET, a testing infrastructure</a>
for autonomous vehicles and related technologies. As new components such as sensors and other monitoring equipment are installed on roads and highways in and around the university’s campus, researchers will be able to evaluate a range of advanced technologies. For instance, we’ll use cars that can talk to the other elements of the system, including each other, and can drive themselves on roads equipped with sensors to monitor traffic conditions.</p>
<p>In preliminary simulations, we have found real savings in travel time with self-driving vehicles that can communicate with their surroundings and adjust their paths on the go. For example, when self-driving cars and traffic lights can talk to each other, they can adjust cars’ speeds and the timing of red and green lights to help every car move more smoothly. Depending on the level of traffic and the number of self-driving cars mixed into human-driven traffic, travel times can <a href="https://doi.org/10.1016/j.trc.2014.10.001">drop by 16 to 36 percent</a>, which may save nearly a minute of delay per car.</p>
<p>On highways, a <a href="https://ops.fhwa.dot.gov/publications/fhwahop14020/sec1.htm">major bottleneck happens around on-ramps</a>, where entering vehicles may have trouble finding openings in fast-moving traffic. When frustrated drivers force their way onto the road, nearby cars must brake abruptly and <a href="http://www.baltimoresun.com/news/breaking/bs-md-co-accident-death-20111228-story.html">may even crash</a>. I helped <a href="https://doi.org/10.1016/j.trc.2017.04.015">develop an algorithm</a> that uses information from self-driving vehicles to plan optimal paths for them. It can tell the cars already on the highway to move to the leftmost lane, making room for entering vehicles. Our simulations show that everyone’s collective travel time can be reduced by as much as 35 percent for the area around the on-ramp, or about 40 seconds per vehicle when traffic is heavy.</p>
<p>This type of intercar communication, coupled with the involvement of road sensors on the highway and in the on-ramp, can be built only if governments, contractors and international car manufacturers work together. That can ensure not only that individual vehicles are safe but also that the entire traffic system functions efficiently.</p><img src="https://counter.theconversation.com/content/84178/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lily Elefteriadou receives funding from Florida Department of Transportation, US DOT, NSF, and the National Cooperative Highway Research Program. She is affiliated with the American Society of Civil Engineers (ASCE), the Institute of Transportation Engineers (ITE), the Transportation Research Board, ITS America, and the Women in Transportation Seminar (WTS). She works for the University of Florida. </span></em></p>If all the elements in the transportation system are going to talk to each other, the people at the companies and government agencies that make those items need to talk to each other too.Lily Elefteriadou, Professor of Civil Engineering; Director of University of Florida Transportation Institute, University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/847742017-10-02T18:42:03Z2017-10-02T18:42:03ZStuck in traffic: we need a smarter approach to congestion than building more roads<p>The equation doesn’t look pretty. Traffic congestion costs us <a href="https://bitre.gov.au/publications/2015/files/is_074.pdf">billions of dollars</a> each year – so we are told – and population growth is not letting up. When road rage meets large economic costs, it’s little wonder our politicians are desperate to do something.</p>
<p>The trouble is, too often that “something” is a great big new freeway. Building more roads <a href="https://theconversation.com/do-more-roads-really-mean-less-congestion-for-commuters-39508">isn’t the best answer</a>, because the roads we have are mostly up to the job – if only we could make better use of them by spreading traffic out beyond the morning and evening peaks. </p>
<p>Instead of focusing on freeways, governments should change the way we pay for urban roads and public transport. To work out how best to do this, the Grattan Institute <a href="https://grattan.edu.au/wp-content/uploads/2017/10/892-Road-congestion.pdf">has looked at</a> several million Google Maps estimates of travel times in Australia’s largest cities. This analysis reveals both the extent of the problem in Sydney and Melbourne and its city-specific characteristics. </p>
<h2>For many, the problem is minor</h2>
<p>The truth is, for a lot of people, road congestion doesn’t matter much. This is because most people work in a suburb close to where they live. </p>
<p>Chart 1 shows congestion delays for Sydney’s 146 most-common commuting trips.</p>
<p><strong>Chart 1: For many Sydney commuters, congestion is very modest</strong></p>
<p><strong>Additional minutes compared to free flow</strong></p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/188305/original/file-20171002-12155-1detu38.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/188305/original/file-20171002-12155-1detu38.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/188305/original/file-20171002-12155-1detu38.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/188305/original/file-20171002-12155-1detu38.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/188305/original/file-20171002-12155-1detu38.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/188305/original/file-20171002-12155-1detu38.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/188305/original/file-20171002-12155-1detu38.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/188305/original/file-20171002-12155-1detu38.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The horizontal black line in the coloured bar is the median of all journey-to-work routes, weighted by the number of people who used a car to travel to work on those routes in the 2011 Census reference week. Trip times were estimated by assuming all travel between suburbs was between representative addresses for each suburb. Routes with fewer than 400 such commuters are not included.</span>
<span class="attribution"><span class="source">Grattan analysis of Google Maps, and ABS (2011)</span></span>
</figcaption>
</figure>
<p>The <em>average</em> delay is small: an average commute at the busiest time of day takes around three minutes longer than the same trip in the middle of the night. </p>
<p>While some commutes are delayed for much longer, it is unusual for trips to take more than ten minutes extra in peak periods. </p>
<h2>Congestion is a problem in the CBD and inner suburbs</h2>
<p>Unsurprisingly, the story is different, and worse, in and around central Sydney and Melbourne. Add in all the trucks and vans, students and tradies, shoppers and people going to appointments, and typical delays for travel on CBD-bound journeys are substantially greater (Chart 2). </p>
<p><strong>Chart 2: On commutes into Sydney’s CBD, the average morning-peak delay is 11 minutes</strong> </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/188306/original/file-20171002-12163-u7fwz0.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/188306/original/file-20171002-12163-u7fwz0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/188306/original/file-20171002-12163-u7fwz0.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/188306/original/file-20171002-12163-u7fwz0.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/188306/original/file-20171002-12163-u7fwz0.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/188306/original/file-20171002-12163-u7fwz0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/188306/original/file-20171002-12163-u7fwz0.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/188306/original/file-20171002-12163-u7fwz0.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The horizontal black line in the coloured bar is the median of all journey-to- work routes, weighted by the number of people who used a car to travel to work on those routes in the 2011 Census reference week. Trip times were estimated by assuming all travel between suburbs was between representative addresses for each suburb. Routes with fewer than 400 such commuters are not included.</span>
<span class="attribution"><span class="source">Grattan analysis of Google Maps, and ABS (2011)</span></span>
</figcaption>
</figure>
<p>The trends are similar in Melbourne. Travel on CBD-bound journeys is much more delayed than to non-CBD locations. </p>
<p>Chart 3 also shows that delays are noticeably larger in the suburbs that immediately surround Melbourne’s CBD. </p>
<p><strong>Chart 3: Travel in suburbs surrounding the Melbourne CBD is highly delayed</strong></p>
<p><strong>Increase in travel time relative to free flow travel time</strong></p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/188307/original/file-20171002-12132-ps1pb5.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/188307/original/file-20171002-12132-ps1pb5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/188307/original/file-20171002-12132-ps1pb5.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=356&fit=crop&dpr=1 600w, https://images.theconversation.com/files/188307/original/file-20171002-12132-ps1pb5.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=356&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/188307/original/file-20171002-12132-ps1pb5.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=356&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/188307/original/file-20171002-12132-ps1pb5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=448&fit=crop&dpr=1 754w, https://images.theconversation.com/files/188307/original/file-20171002-12132-ps1pb5.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=448&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/188307/original/file-20171002-12132-ps1pb5.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=448&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Average delay is calculated as the ratio of trip duration at each point throughout the day to the minimum trip duration observed for that route over the sample period. Based on travel time of representative route samples collected via Google Maps. Weekends and public holidays excluded.</span>
<span class="attribution"><span class="source">Grattan analysis of Google Maps</span></span>
</figcaption>
</figure>
<h2>Some commutes are frustratingly unpredictable</h2>
<p>Most travellers don’t just care about how long a trip usually takes. How long it <em>could</em> take also matters. </p>
<p>Chart 4 shows that Melbourne’s Eastern Freeway/Hoddle Street corridor has not only some of city’s worst delays, but also some of the least-predictable travel times. Motorists from suburbs to the north-east have to juggle these less-reliable travel times more than those travelling similar distances from other directions. </p>
<p><strong>Chart 4: Travel on routes to Melbourne’s CBD that rely on Eastern Freeway and Hoddle Street are noticeably delayed and unreliable</strong> </p>
<p><strong>Increase in travel time as a proportion of free-flow travel time, weekday morning peak, commutes into Melbourne CBD</strong></p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/188308/original/file-20171002-12115-g3b13o.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/188308/original/file-20171002-12115-g3b13o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/188308/original/file-20171002-12115-g3b13o.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=510&fit=crop&dpr=1 600w, https://images.theconversation.com/files/188308/original/file-20171002-12115-g3b13o.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=510&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/188308/original/file-20171002-12115-g3b13o.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=510&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/188308/original/file-20171002-12115-g3b13o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=640&fit=crop&dpr=1 754w, https://images.theconversation.com/files/188308/original/file-20171002-12115-g3b13o.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=640&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/188308/original/file-20171002-12115-g3b13o.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=640&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">For travel departing between 7am and 9 am. Excludes weekends and public holidays. The boxes cover the 25th to 75th percentiles. The vertical line in each box lies at the median for each city. The ‘whiskers’ on each side of the boxes extend no further than plus or minus 1.5w where ‘w’ is the box width. Observations beyond the lines are plotted as dots.</span>
<span class="attribution"><span class="source">Grattan analysis of Google Maps</span></span>
</figcaption>
</figure>
<h2>New roads are not the whole answer</h2>
<p>Congestion tends to be worst in the most built-up parts of Sydney and Melbourne, where it would be most costly to construct new roads. This means that even crippling levels of congestion might not justify the construction of astronomically expensive infrastructure. </p>
<p>In any case, new roads often take years to build and can fill up with new traffic of their own. </p>
<p>New roads are important, however, in new suburbs. </p>
<p>The rule for our policymakers should be: build a road whenever the community will gain more from the new road than it will cost, and whenever the new road is a better option for the community than extracting more from the roads we’ve already got. But do not think of new roads as congestion-busting. </p>
<h2>So what should be done?</h2>
<p>Changing the way we use our existing infrastructure through pricing needs to be at the top of the agenda. This mean charging motorists for the congestion they cause.</p>
<p>Sydney and Melbourne need to consider introducing a congestion charge. That doesn’t mean more toll roads – it means charging people who drive at peak times on congested roads a small fee.</p>
<hr>
<p><em><strong>Further reading:</strong> <a href="https://theconversation.com/road-user-charging-belongs-on-the-political-agenda-as-the-best-answer-for-congestion-management-65027">Road user charging belongs on the political agenda as the best answer for congestion management</a></em></p>
<hr>
<p>Because some people wouldn’t think it worth paying the charge at the busiest times of day, those who <em>did</em> pay would get a quicker and more reliable trip. People who can travel outside of the peaks would not have to pay, because there would be no congestion charge when the roads are not congested.</p>
<p>The increased cost to drivers could be offset by cuts to car registration fees. And any extra money raised by the congestion charge could be spent improving train, tram, bus and ferry services.</p>
<p>International examples show that introducing a congestion charge need not amount to political suicide. An initially sceptical public came quickly to accept, value, the reform when it was introduced in <a href="http://pubs.aeaweb.org/doi/pdfplus/10.1257/jep.20.4.157">London</a> and <a href="http://www.transportportal.se/swopec/cts2014-7.pdf">Stockholm</a>.</p>
<p>The congestion equation for Sydney and Melbourne is only going to get more ugly as both cities continue to grow. We need more sophisticated policymaking to ease drivers’ road rage and frustrations.</p><img src="https://counter.theconversation.com/content/84774/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Grattan Institute began with contributions to its endowment of $15 million from each of the Federal and Victorian Governments. In order to safeguard its independence, Grattan Institute’s board controls this endowment. The funds are invested and Grattan uses the income to pursue its activities.
Marion Terrill and Hugh Batrouney do not work for, consult, own shares in or receive funding from any other company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond the academic appointment above.</span></em></p><p class="fine-print"><em><span>Grattan Institute began with contributions to its endowment of $15 million from each of the Federal and Victorian Governments. In order to safeguard its independence, Grattan Institute’s board controls this endowment. The funds are invested and Grattan uses the income to pursue its activities. Marion Terrill and Hugh Batrouney do not work for, consult, own shares in or receive funding from any other company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond the academic appointment above.</span></em></p>Instead of focusing on freeways, governments should change the way we pay for urban roads and public transport.Marion Terrill, Transport Program Director, Grattan InstituteHugh Batrouney, Senior Associate, Grattan InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/828552017-10-02T10:11:23Z2017-10-02T10:11:23ZIndonesia’s fuel subsidy cuts prevented even worse traffic jams<p>Indonesia is notorious for its traffic jams. Many people spend <a href="http://www.nytimes.com/2013/08/05/world/asia/hours-to-go-just-to-get-to-work.html?_r=2">hours</a> commuting each day. Jakarta and other Indonesian cities have been <a href="http://www.castrol.com/en_au/australia/car-engine-oil/engine-oil-brands/castrol-magnatec-brand/stop-start-index.html">rated</a> as home to some of the world’s slowest traffic.</p>
<p>The many causes of Indonesia’s traffic challenges include high population density and a shortage of public transport. </p>
<p>Fuel subsidies have also played a role. In early 2013, petrol was sold for just <a href="https://www.giz.de/expertise/html/4317.html">4,500 rupiah</a> (US 46 cents) per litre, well below the cost of supply.</p>
<h2>Cheap petrol? Let’s drive!</h2>
<p>In a newly-published <a href="http://www.sciencedirect.com/science/article/pii/S0965856416308102">study</a>, two co-authors and I explore the link between Indonesia’s fuel subsidies and its traffic.</p>
<p>Using data for 19 toll roads in Greater Jakarta and elsewhere in Indonesia over the period 2008–2015, we find that supplying below-cost fuel contributed to rapid growth in road use.</p>
<p>In a sequence of important reforms, President Susilo Bambang Yudhoyono (<a href="http://www.nytimes.com/2013/05/03/business/global/03iht-subsidy03.html">in 2013</a>) and President Joko Widodo (<a href="http://www.thejakartapost.com/news/2014/11/18/govt-slashes-fuel-subsidies.html">in 2014</a>) implemented overnight increases in fuel prices to reduce subsidy spending.</p>
<hr>
<p><em><strong>Further reading:</strong> <a href="https://theconversation.com/indonesias-fuel-subsidy-cut-a-bitter-pill-that-had-to-be-swallowed-34357">Indonesia’s fuel subsidy cut, a bitter pill that had to be swallowed</a></em></p>
<hr>
<p>When fuel prices go up, people have an incentive to economise on their driving by taking steps such as car-pooling or catching public transport.</p>
<p>Our paper finds that there is now around 10% less traffic on the toll roads than would have been the case without the 2013 and 2014 subsidy reforms. Traffic continued to increase even after the reforms, but more slowly than would have been the case if the reforms had not gone ahead.</p>
<p>Our paper adds to evidence on the effects of public policies on road traffic in Indonesia. A recent paper in <a href="http://science.sciencemag.org/content/357/6346/89">Science</a> analysed the impact of the 2016 removal of Jakarta’s three-in-one vehicle policy.</p>
<h2>More to cut</h2>
<p>Indonesia’s fuel subsidy reforms made sense for a lot of reasons. As well as fuelling traffic jams, the subsidies placed a <a href="https://www.indonesia-investments.com/news/todays-headlines/ever-growing-fuel-and-electricity-subsidies-burden-indonesias-state-budget/item2078">large burden</a> on the central budget. Subsidising road transport fuels is a <a href="http://documents.worldbank.org/curated/en/118181468044121438/Why-is-reducing-energy-subsidies-a-prudent-fair-and-transformative-policy-for-Indonesia">regressive</a> form of spending in Indonesia. More driving means more pollution.</p>
<p>The subsidies have yet to disappear entirely. Pertamina, the national oil company, is still exposed <a href="http://www.thejakartapost.com/news/2015/10/01/govt-cover-pertamina-s-losses-fuel-sales.html">to losses</a> on its sales. A fixed per-litre subsidy for diesel also remains in place. There are thus more subsidies to be cut.</p>
<h2>Looking to a neighbour</h2>
<p>Singapore has <a href="http://onlinelibrary.wiley.com/doi/10.1002/app5.39/full">led the way</a> in the use of economic instruments to manage road traffic. There is scope for Indonesia to take steps to emulate its small neighbour.</p>
<p>Among the approaches used in Singapore is an <a href="https://www.lta.gov.sg/content/ltaweb/en/roads-and-motoring/managing-traffic-and-congestion/electronic-road-pricing-erp.html">electronic road pricing</a> system on congested roads. Singapore also has fuel excise and a <a href="https://www.lta.gov.sg/content/ltaweb/en/roads-and-motoring/owning-a-vehicle/vehicle-quota-system/overview-of-vehicle-quota-system.html">cap-and-trade scheme</a> for vehicle ownership.</p>
<p>Together with a high-quality public transport system, these policies have helped Singapore avoid the sort of traffic jams seen in Indonesia.</p>
<h2>The road ahead</h2>
<p>Reforms could be on the agenda in Indonesia also.</p>
<p>A trial of electronic road pricing has been <a href="http://jakarta.coconuts.co/2016/07/25/ahok-signs-governors-order-begin-electronic-road-pricing-construction-hopes-system-will">proposed</a> for Jakarta, although it has been delayed. This approach would be relevant in other Indonesian cities too.</p>
<p>A new fuel excise would also be an attractive way forward. Fuel excise is a smart tax for several reasons. The administrative costs of collecting excise are low, as there are only a few fuel retailers in Indonesia. Fuel excise helps to ease congestion, pollution and road crash risks. Revenue could be used to cut other taxes, reduce Indonesia’s budget deficit, or meet key spending priorities.</p>
<p>Public transport is also important. The first line of Jakarta’s <a href="http://jakartamrt.co.id/">Mass Rapid Transit</a> (MRT) system is under construction. There is a long way to go, however, before the city could match the mass transport infrastructure of cities such as <a href="https://en.wikipedia.org/wiki/Beijing_Subway">Beijing</a>.</p>
<p>Indonesia’s experience provides a reminder of the benefits of getting policy settings right as early as possible in the development process. </p>
<p>Fuel subsidies and a lack of investment in public transport can, unfortunately, end up with the traffic in a jam.</p>
<hr>
<p><em>An open access version of the research is available <a href="https://ideas.repec.org/p/pas/papers/2017-10.html">here</a>.</em></p><img src="https://counter.theconversation.com/content/82855/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Burke receives funding from the Australian Research Council (DE160100750).</span></em></p>Traffic continues to increase, but more slowly than would have been the case if the reforms had not gone ahead.Paul Burke, Fellow, Crawford School of Public Policy, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/762582017-04-19T22:34:40Z2017-04-19T22:34:40ZCalculating where America should invest in its transportation and communications networks<figure><img src="https://images.theconversation.com/files/165883/original/file-20170419-2410-x9z679.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Which links are most important in road and information networks?</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/network-connection-technology-concept-city-background-436942042">Sahacha Nilkumhang/Shutterstock.com</a></span></figcaption></figure><p>The American economy is underpinned by networks. Road networks carry traffic and freight; the internet and telecommunications networks carry our voices and digital information; the electricity grid is a network carrying energy; financial networks transfer money from bank accounts to merchants. They’re vast, often global systems – but a local disruption can really block them up.</p>
<p>For example, <a href="http://www.wsbtv.com/news/local/atlanta/gdot-state-offering-31m-in-incentives-to-reopen-i-85-before-june/511832846">the I-85 bridge collapse in Atlanta will affect that city’s traffic for months</a>. A seemingly minor train derailment at New York City’s Penn Station resulted in <a href="https://www.nytimes.com/2017/04/04/nyregion/messy-commute-for-nj-transit-and-lirr-riders-a-day-after-derailment.html?_r=0">multiple days of travel chaos</a> in April. </p>
<p>As the Trump administration plans to <a href="http://thehill.com/blogs/congress-blog/economy-budget/328586-an-infrastructure-plan-coming-but-when">invest hundreds of billions in American infrastructure networks</a>, it will be crucial to identify what elements are the most crucial to repair or improve. This is not only important for maximizing benefits; it’s also useful in preventing disaster. Is there, perhaps, a telecommunication line that would be particularly damaging if it were destroyed? Or one road through an area that has an especially large role in keeping traffic flowing smoothly?</p>
<p><a href="http://greatvalley.psu.edu/person/qiang-patrick-qiang">Patrick Qiang</a> and I are operations management scholars who have developed <a href="http://dx.doi.org/10.1007/s10898-007-9198-1">a way to evaluate network performance</a> and simulate the effects of potential changes, whether planned (like a highway repair) or unexpected (like a natural disaster). By modeling the independent behavior of all the users of a network, we can calculate the flow – of <a href="http://dx.doi.org/10.1007/s10898-015-0371-7">freight</a>, <a href="https://dx.doi.org/10.1209/0295-5075/79/38005">commuters</a>, <a href="http://dx.doi.org/10.1007/978-3-540-77958-2_14">money</a> or anything else – across each link, and how other links’ flows will change. This lets us identify where investment will be most beneficial, and which projects shouldn’t happen at all.</p>
<h2>More isn’t always better</h2>
<p>It’s very difficult to measure networks’ performance, in part because they are so complex, but also because people use them differently at different times, and because those choices affect others’ experiences. For example, one person choosing to drive to work instead of taking the bus puts one more car on the road, which might get involved in a crash or otherwise contribute to a traffic jam.</p>
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<figcaption><span class="caption">Explaining the Braess paradox.</span></figcaption>
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<p>In 1968, German mathematician Dietrich Braess observed the possibility that adding a road to an area with congested traffic <a href="http://dx.doi.org/10.1287/trsc.1050.0127">could actually make things worse</a>, not better. <a href="https://supernet.isenberg.umass.edu/braess/braess-new.html">This paradox</a> can occur when travel times depend on the amount of traffic. If too many drivers decide their own optimal route involves one particular road, that road can become congested, slowing everyone’s travel time. In effect, the drivers would have been better off if the road hadn’t been built.</p>
<p>This phenomenon has been found not only <a href="https://supernet.isenberg.umass.edu/braess/braess-new.html#BraessArticle">in transportation networks</a> and <a href="http://dx.doi.org/10.1239/jap/1032374242">the internet</a>, but also, recently, <a href="https://doi.org/10.1209/0295-5075/115/28004">in electrical circuits</a>. </p>
<p>We shouldn’t waste time and money building or repairing network links the community would be better without. But how can we tell which elements help and which make things worse?</p>
<h2>Calculating efficiency</h2>
<p>The best networks can handle the highest demand at the lowest average cost for each trip – such as a commute from a worker’s home to her office. Evaluating a network means identifying which locations need to be connected to each other, as well as the volume of traffic between specific places and the various costs involved – such as gas, pavement wear and tear, and police services keeping drivers safe.</p>
<p>Once a network is measured in this way, it can be converted into a computerized model where we can simulate removing links or adding new ones in particular places. Then we can measure what happens to the rest of the network: Does traffic get more congested, and if so, by how much? Or, as in the Braess paradox, do travel times actually get shorter when a link is removed? And how much money does a particular project cost to build, and save in time or user expenses?</p>
<h2>Going global</h2>
<p>Our method of measuring a network’s performance has been used to refine
<a href="https://ercim-news.ercim.eu/en79/rd/route-optimization-how-efficient-will-the-proposed-north-dublin-metro-be">the route of a proposed metro line in Dublin, Ireland</a>; <a href="https://www.researchgate.net/publication/313365965_Maritime_Network_Efficiency_Comparison_in_Indonesia_Nusantara_Pendulum_and_Sea_Tollway">to design new shipping routes in Indonesia</a>; <a href="http://www.cedim.de/download/14_Schulz.pdf">to identify which roads in Germany should be first on the maintenance list</a>; and <a href="http://dx.doi.org/10.1007/s11069-013-0896-3">to determine the effects of road closures after major fires in regions of Greece</a>.</p>
<p>Our method has also been applied to make supply chains more efficient, both to <a href="http://dx.doi.org/10.1007/978-1-84882-634-2_6">maximize profits</a> and to <a href="http://www.sciencedirect.com/science/article/pii/S0965856412000249">speed disaster relief supplies</a> to people in need.</p>
<p>As the U.S. works to enhance its economic competitiveness, the country will need to invest in many different types of networks, to maximize their usefulness and value to Americans. Using measurement methods like ours can guide leaders to wise investments.</p><img src="https://counter.theconversation.com/content/76258/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anna Nagurney does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>When planning major infrastructure investments, it’s important to know which road, freight and information networks are most important – and which proposals might make things worse, not better.Anna Nagurney, John F. Smith Memorial Professor of Operations Management, UMass AmherstLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/634622016-08-30T11:28:32Z2016-08-30T11:28:32ZHow maths and driverless cars could spell the end of traffic jams<p>Being stuck in miles of halted traffic is not a relaxing way to start or finish a summer holiday. And as we crawl along the road, our views blocked by by slow-moving roofboxes and caravans, many of us will fantasise about a future free of traffic jams. </p>
<p>As a mathematician and motorist, I view traffic as a complex system, consisting of many interacting agents including cars, lorries, cyclists and pedestrians. Sometimes these agents interact in a free-flowing way and at other (infuriating) times they simply grind to a halt. All scenarios can be examined – and hopefully improved – using <a href="http://www.bath.ac.uk/imi/index.html">mathematical modelling</a>, a way of describing the world in the language of maths.</p>
<p>Mathematical models tell us for instance that if drivers kept within the <a href="http://www.theaa.com/motoring_advice/safety/smart-motorways.html">variable speed limits</a> sometimes displayed on a motorway, <a href="http://www.nytimes.com/roomfordebate/2010/8/26/redefining-bumper-to-bumper/the-ripple-effect-of-bad-driving">traffic would flow consistently</a> at, say, 50mph. Instead we tend to drive more aggressively, accelerating as soon as the opportunity arises – and being forced to brake moments later. The result is <a href="http://www.dft.gov.uk/vca/fcb/smarter-driving-tips.asp">greater fuel consumption</a> and a longer overall journey time. Cooperative driving seems to go against human nature when we get behind the wheel. But could this change if our roads were taken over by <a href="https://theconversation.com/where-we-are-on-the-road-to-driverless-cars-50079">driverless cars</a>?</p>
<p>Incorporating driverless cars into mathematical traffic models will prove key to improving traffic flow and assessing the various conditions in which traffic reaches a traffic jam threshold, or “jamming density”. The chances of reaching this point are affected by changes such as road layout, traffic volume and traffic light systems. And crucially, they are affected by whoever is in control of the vehicles.</p>
<p>In mathematical analysis, dense traffic can be treated as a flow and modelled using differential <a href="http://www.wired.com/2010/06/st_equation_traffic/">equations</a> which describe the movement of fluids. <a href="http://www.worldscientific.com/doi/abs/10.1142/S0217595907001383?src=recsys">Queuing models</a> consider individual vehicles on a network of roads and the expected time they spend both in motion and waiting at junctions. </p>
<p><a href="https://theory.org/complexity/traffic/">Another type of model</a> consists of a grid in which cars’ positions are updated, according to certain rules, from one grid cell to the next. These rules can be based on their current velocity, acceleration and deceleration due to other vehicles and random events. This random deceleration is included to account for situations caused by something other than other vehicles – a pedestrian crossing the road for example, or a driver distracted by a passenger. </p>
<p>Adaptations to such models can take into account factors such as traffic light synchronisation or road closures, and they will need to be adapted further to take into account the movement of driverless cars.</p>
<p>In theory, autonomous cars will typically drive within the speed limits, have faster reaction times allowing them to drive closer together and will behave less randomly than humans, who tend to overreact in certain situations. On a tactical level, choosing the optimum route, accounting for obstacles and traffic density, driverless cars will behave in a more rational way, as they can communicate with other cars and quickly change route or driving behaviour.</p>
<h2>It all adds up</h2>
<p>So driverless cars may well make the mathematician’s job easier. Randomness is often introduced into models in order to incorporate unpredictable human behaviour. A system of driverless cars should be simpler to model than the equivalent human-driven traffic because there is less uncertainty. We could predict exactly how individual vehicles respond to events. </p>
<p>In a world with only driverless cars on the roads, computers would have full control of traffic. But for the time being, to avoid traffic jams we need to understand how autonomous and human-driven vehicles will interact together. </p>
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<p>Of course, even with the best modelling, cooperative behaviour from driverless cars is not guaranteed. Different manufacturers might compete to come up with the best traffic-controlling software to ensure their cars get from A to B faster than their rivals. And, like the behaviour of individual human drivers, this could negatively affect everyone’s journey time. </p>
<p>But even supposing we managed to implement rules that optimised traffic flow for everyone, we could still get to the point where there are simply too many cars on the road, and jamming density is reached. Yet there is still potential for self-driving cars to help in this scenario. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/135923/original/image-20160830-28240-1i2sq4f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/135923/original/image-20160830-28240-1i2sq4f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/135923/original/image-20160830-28240-1i2sq4f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/135923/original/image-20160830-28240-1i2sq4f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/135923/original/image-20160830-28240-1i2sq4f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/135923/original/image-20160830-28240-1i2sq4f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/135923/original/image-20160830-28240-1i2sq4f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Are we nearly at a mathematical solution yet?</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-127870775/stock-photo-little-boy-in-a-child-safety-seat-sitting-patiently-in-the-back-of-a-car-with-his-hands-behind-his-head-staring-out-of-the-window.html?src=CEq_IS1fMdJaJ4KxVLgY7A-1-3">Shutterstock</a></span>
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<p>Some car makers expect that eventually we will <a href="https://www.theguardian.com/technology/2014/jun/01/google-self-driving-pods-end-of-road-car-ownership">stop viewing cars as possessions</a> and instead simply <a href="https://theconversation.com/driverless-cars-will-change-the-way-we-think-of-car-ownership-50125">treat them as a transport service</a>. Again, by applying mathematical techniques and modelling, we could optimise how this shared autonomous vehicle service could operate most efficiently, reducing the overall number of cars on the road. So while driverless cars alone might not rid us of traffic jams completely by themselves, an injection of mathematics into future policy could help navigate a smoother journey ahead.</p><img src="https://counter.theconversation.com/content/63462/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lorna Wilson does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>If computers ruled the roads, we might be out of a jam.Lorna Wilson, Commercial Research Associate, University of BathLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/561352016-03-15T16:08:36Z2016-03-15T16:08:36ZRecalculating! By not driving the optimal route, you’re causing traffic jams<figure><img src="https://images.theconversation.com/files/115139/original/image-20160315-9246-13arlxt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Drivers make some suboptimal routing decisions when they're traveling around town.</span> <span class="attribution"><span class="source">A. Lima et al. J. R. Soc. Int. DOI: 10.1098/rsif.2016.0021</span>, <span class="license">Author provided</span></span></figcaption></figure><p>If you use a car to get around, every time you get behind the wheel you’re confronted with a choice: how will you navigate to your destination? Whether it’s a trip you take every day, such as from home to work, or to someplace you haven’t been before, you need to decide on a route.</p>
<p>Transportation research has traditionally assumed that drivers are very rational and choose the optimal route that minimizes travel time. Traffic prediction models are based on this seemingly reasonable assumption. Planners use these models in their efforts to keep traffic flowing freely – when they evaluate a change to a road network, for instance, or the impact of a new carpool lane. In order for traffic models to be reliable, they must do a good job reproducing user behavior. But there’s little empirical support for the assumption at their core – that drivers will pick the optimal route.</p>
<p>For that reason, we decided to investigate how people make these choices in their real lives. Understanding how drivers build a route to reach their destination will help us gain insights into <a href="https://en.wikipedia.org/wiki/Individual_mobility">human movement behavior</a>. Better knowledge of individual routing can help improve urban infrastructure and GPS directions systems – not just for one driver, but for everyone. Beating congestion is a big goal: one estimate put the <a href="http://mobility.tamu.edu/ums/report/">cost of traffic in 2014</a> at US$160 billion in the U.S., with 42 extra hours of travel time and $960 worth of extra fuel for every commuter.</p>
<h2>How do people really go?</h2>
<p>Using GPS data collected for several months for hundreds of drivers in four European cities, we <a href="http://doi.org/10.1098/rsif.2016.0021">studied individuals’ routing behavior</a>, looking for interesting patterns in their choices.</p>
<p>We discovered that people use only a few routes when moving between their relevant places, even when those trips are repeated again and again over extended periods. Most people have a single favorite route for trips they perform routinely and a few alternatives routes they take less frequently to the same destinations.</p>
<p>So did people in fact usually choose the optimal route?</p>
<p>In short, no. It turned out roughly half of the favorite routes are not the optimal routes suggested by navigation devices, such as those offered by some popular mapping apps for smartphones. If we also consider drivers’ alternative choices, even fewer routes are optimal – only a third overall minimize travel time.</p>
<p>Our data provide empirical proof that drivers are not taking the optimal route, directly contradicting the shortest travel-time assumption.</p>
<h2>Why would drivers take a nonoptimal route?</h2>
<p>What’s behind this result? A unique answer that is valid for every driver won’t be easy to find.</p>
<p>Prior small-scale studies found that many factors, some seemingly minor, might influence route preference. For example, people tend to <a href="http://doi.org/10.3758/MC.38.6.700">choose routes going south</a> rather than routes of equal lengths that go north. People favor routes that are <a href="http://doi.org/10.3758/BF03213808">straight at the beginning</a>, instead of shorter ones that aren’t straight. <a href="http://doi.org/10.1016/j.jtrangeo.2015.01.006">Landmarks also influence route choice</a>, by attracting more trips than travel-time minimization would expect. A <a href="https://likeways.wordpress.com">novel app for iPhones</a> builds on that very concept and allows people to find the most “interesting” route between two points.</p>
<p>People might not be able to determine which route is optimal, among all possible choices, because of limited information and limited ability to process big amounts of information. Or, even if they can, people might deliberately make different choices, according to personal preference. Many factors can influence preference, including fuel consumption, route reliability, <a href="http://doi.org/10.1140/epjds/s13688-015-0038-0">simplicity and pleasure</a>.</p>
<p>Drivers’ apparent flexibility on route choices may provide an opportunity to <a href="http://doi.org/10.1038/ncomms10793">alleviate overall congestion</a>. For instance, smartphone apps could offer points and vouchers to drivers who are willing to take longer routes that avoid congested areas. Navigation app <a href="http://www.citylab.com/commute/2015/04/las-lovehate-relationship-with-waze-continues/391832/">Waze has already changed</a> drivers’ habits in some cities, so it’s not so far-fetched to imagine a <a href="https://theconversation.com/gamification-harnesses-the-power-of-games-to-motivate-37320">gamification system</a> that reduces congestion.</p>
<h2>How far from the best route are we?</h2>
<p>For our next study, rather than trying to understand what drives individual route choices, we aimed to quantify how far those choices are from optimal.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/114888/original/image-20160312-11288-1wsin9n.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/114888/original/image-20160312-11288-1wsin9n.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/114888/original/image-20160312-11288-1wsin9n.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=595&fit=crop&dpr=1 600w, https://images.theconversation.com/files/114888/original/image-20160312-11288-1wsin9n.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=595&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/114888/original/image-20160312-11288-1wsin9n.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=595&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/114888/original/image-20160312-11288-1wsin9n.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=748&fit=crop&dpr=1 754w, https://images.theconversation.com/files/114888/original/image-20160312-11288-1wsin9n.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=748&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/114888/original/image-20160312-11288-1wsin9n.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=748&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A sample of the transformed trajectories reveals the shape of human routes. Regardless of the real start and destination points, every transformed trajectory begins at the circle on the left and ends at the circle on the right.</span>
<span class="attribution"><span class="source">A. Lima et al. J. R. Soc. Int. DOI: 10.1098/rsif.2016.0021</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>It’s hard to directly compare all the different trips undertaken in a city, because they involve many locations and are different in length. To make this task easier, we transformed trajectories so that they all look alike, regardless of their actual source, destination and length. We rotated, translated and scaled each route so that all trajectories would start and finish at the same two points in a new reference system. After this transformation, <em>all</em> the routes look as if they spanned the same two points; they all look similar in length, but their shape is preserved. What we found by plotting a sample of the transformed routes was the intrinsic variability in human routes.</p>
<p>Intriguingly, our abstraction of all the trips sort of looks like a magnet’s force lines, with the routes’ origins and destinations in place of the magnet’s north and south poles. By analyzing a density plot of the transformed trajectories, we found the vast majority are fully contained within an ellipse that has the same shape independent of the scale, with the start and endpoints as foci. This ellipse effectively makes up the boundary of human routes.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/114889/original/image-20160312-11282-mkfy45.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/114889/original/image-20160312-11282-mkfy45.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/114889/original/image-20160312-11282-mkfy45.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/114889/original/image-20160312-11282-mkfy45.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/114889/original/image-20160312-11282-mkfy45.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/114889/original/image-20160312-11282-mkfy45.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/114889/original/image-20160312-11282-mkfy45.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/114889/original/image-20160312-11282-mkfy45.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The density plot shows how likely you are to be at any position between the start (on the left) and the destination (on the right). Colors indicate, in logarithmic scale, from dark to bright, the spots more likely to be occupied by drivers on that trip.</span>
<span class="attribution"><span class="source">Antonio Lima</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The ellipse also helps us measure how direct a route is. The ellipse’s <em>eccentricity</em> tells us how elongated it is. An eccentricity close to 1 means the ellipse is similar to a line (high width and low height), while an eccentricity close to 0 means it is similar to a circle (width and height roughly similar).</p>
<p>Generally, a straight route is not a viable option because of physical obstacles, such as buildings. Drivers deviate from that idealized shortest path according to the street network and personal preferences. While these two phenomena are hard to model, we found that they are bounded by a ellipse of a particular shape, having a high eccentricity equal to 0.8. </p>
<p>To our surprise, the observed shape of the ellipse did not change with distance between the endpoints. It looks like in an urban setting, drivers are willing to take detours that are roughly proportional to the distance between their starting point and destination. Routes that involve bigger detours are simply not taken, or split into two separate trips.</p>
<p>Our study uncovered basic rules of a realistic routing model that captures individual behavior in a urban environment. These findings can be used as building blocks for new routing models that better predict traffic. And now that we know drivers have some quantifiable flexibility in their routes, we can use this information to design incentive mechanisms to alleviate congestion on busier roads, or carpooling plans based on individuals’ preferred routes.</p><img src="https://counter.theconversation.com/content/56135/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>No wonder you’re always late. Drivers use a route that minimizes travel time on only a third of their trips. Here’s how real-world data can help planners fight traffic congestion.Marta Gonzalez, Associate Professor of Civil and Environmental Engineering, Massachusetts Institute of Technology (MIT)Antonio Lima, Ph.D. student in Computer Science, University of BirminghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/416842015-05-21T03:30:22Z2015-05-21T03:30:22ZThe maths of congestion: springs, strings and traffic jams<figure><img src="https://images.theconversation.com/files/82319/original/image-20150520-30566-78q7bp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The mathematical modelling of traffic networks can throw up conflicting results.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/intherough/3573333256/">Flickr/Wendell</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>It’s not been a good year so far for major transport projects in Australia’s capital cities.</p>
<p>The scale of disagreements over the merits of Melbourne’s proposed East West Link was such that the Victorian Government recently <a href="http://www.abc.net.au/news/2015-04-15/victorian-government-to-pay-339-million-east-west-link-contracts/6393536">paid out $339 million</a> simply for the project not to be built.</p>
<p>In Queensland, Annastacia Palaszczuk became the fourth successive Premier to completely throw out her predecessor’s <a href="http://www.brisbanetimes.com.au/queensland/bat-tunnel-scrapped-as-government-looks-for-different-cross-river-rail-line-20150306-13wiyz.html">signature infrastructure project</a> – in this case the Bus and Train (BaT) Tunnel. </p>
<p>While Sydney’s WestConnex project is still going ahead, recent reports concluded that it will either <a href="http://www.smh.com.au/nsw/parramatta-road-traffic-will-increase-under-westconnex-study-shows-20150427-1mueqm.html">substantially increase traffic</a> on the much-maligned Parramatta Road, or maybe <a href="http://www.westconnex.com.au/documents/westconnex-executive-summary-september-2013.pdf">decrease it</a>. It all depends on which report you believe. </p>
<h2>Why such discrepancies?</h2>
<p>I am not going to debate the relative merits of these schemes. My background is in applied mathematics and not in transport planning. As such, my interest is less in the conclusions of some of these predicted usage studies and more in the consequences of the assumptions made in the modelling.</p>
<p>How can <a href="https://majorprojects.affinitylive.com/public/9cd516477ae2681594d1354d8c5330ee/01_M4Widening_EIS_ExecSumm.pdf">one report</a> filed with the <a href="http://majorprojects.planning.nsw.gov.au/">NSW Major Project register</a> predict 20,000 fewer cars per day on a section of Parramatta Road, while <a href="http://www.smh.com.au/business/world-business/emails-reveal-doubts-on-westconnex-parramatta-road-revival-20140807-10121c">other reports</a> within the Roads and Maritime Services state that no significant reductions are likely to be seen?</p>
<p>It is very easy to chalk up some of these differences either to wildly overoptimistic developers potentially <a href="http://www.smh.com.au/national/westconnex-adviser-engineered-traffic-numbers-on-lane-cove-tunnel-disaster-20140811-102vqf.html">misleading themselves and others</a> to get a project approved. Similarly, it is sometimes alleged that feasibility studies might be influenced by political biases or <a href="http://www.dailytelegraph.com.au/news/nsw/clover-moores-road-project-campaign-against-the-westconnex-is-sentencing-commuters-to-their-cars/story-fni0cx12-1227335226577">pre-established views</a> on the merits of roads or public transport schemes.</p>
<p>While these factors may well influence some decision making, one thing that is often missed in the reporting of such studies is the sheer complexity associated with analysing such networks. Assuming all roads are connected, the behaviour of a whole network can be hyper-sensitive to how individual parts, even seemingly minor ones, function.</p>
<p>A poor estimate of traffic flow in one section of a network can lead to hugely different behaviour across the whole system. Furthermore, even the simplest networks can have the potential to function in some extremely surprising and often counter-intuitive ways.</p>
<p>It is very easy to believe that if a traveller is offered the choice of two routes for a journey that the addition of a third choice should not worsen his/her travel time. If the new route is slower, the traveller could simply ignore the new route and make the same choice as before. </p>
<p>As the German mathematician <a href="http://www.uvm.edu/%7Epdodds/files/papers/others/2005/braess2005a.pdf">Dietrich Braess pointed out</a>, this is not always the case. Increasing the capacity of a network can, perhaps surprisingly, decrease the efficiency of journeys around it even without increasing the number of trips made, as was pointed out in <a href="https://theconversation.com/do-more-roads-really-mean-less-congestion-for-commuters-39508">a recent article</a>.</p>
<h2>The Braess’s Paradox</h2>
<p>To take a closer look at the reasoning behind this paradox, consider the case illustrated below. There are two major cities, labelled as the Start and End locations for a journey.</p>
<p>Travellers between the two cities have two choices of route, either via Town A or via Town B. The roads from Start to Town A and from Town B to End are both highways, which can handle any number of cars and allow them to make each leg of the journey in 105 minutes.</p>
<p>The roads from Start to Town B and from Town A to End are smaller roads which are slower when busy. When there are N cars on the road, each leg of the journey takes N minutes. There is an old road linking Town A to Town B with a journey time of 100 minutes. This road is sufficiently slow that no traveller from Start to Finish would choose a route that involves it.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/81937/original/image-20150516-25432-e7kku5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/81937/original/image-20150516-25432-e7kku5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/81937/original/image-20150516-25432-e7kku5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=269&fit=crop&dpr=1 600w, https://images.theconversation.com/files/81937/original/image-20150516-25432-e7kku5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=269&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/81937/original/image-20150516-25432-e7kku5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=269&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/81937/original/image-20150516-25432-e7kku5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=338&fit=crop&dpr=1 754w, https://images.theconversation.com/files/81937/original/image-20150516-25432-e7kku5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=338&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/81937/original/image-20150516-25432-e7kku5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=338&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Network illustrating Braess’s Paradox. Travel times along routes are listed in minutes.</span>
</figcaption>
</figure>
<p>If we assume that 100 cars are travelling at the same time from Start to End, then there is no advantage to going via Town A vs going via Town B. The traffic will split approximately 50/50 between the two routes and each car will do the journey in 155 minutes. This is the fastest route. In reality, the split of cars might not be exactly 50/50, but unless the ratio is heavily imbalanced, the average travel time across the network will be 155 minutes.</p>
<p>Suppose now that the network is “improved” by upgrading the road between Town A and Town B. Rather than taking 100 minutes to travel between the towns, it now takes only 2 minutes. </p>
<p>The fastest route now is for all drivers to go from Start to Town B in 100 minutes, take the 2 minute trip to Town A, then travel from Town A to End in another 100 minutes. This journey now takes 202 minutes – but that’s 47 minutes longer than on the old road layout. </p>
<p>There is no incentive for any driver to choose an alternative route. Opting for either of the 105 minute roads will only lengthen their trip. A driver can improve travel times for all others by selflessly choosing the slowest roads, but cannot help the overall network without suffering for it in the form of a slower journey. This, of course, is not an option which many will choose.</p>
<p>While the old road between Town A and Town B was hugely inefficient, this inefficiency actually ensured that the network as a whole remained reasonably efficient. It served to distribute traffic evenly between the two routes from Start to End. But by improving this relatively unimportant road, it simply redistributes traffic more unevenly and worsens the overall system.</p>
<p>Even more counter-intuitively, Braess’s Paradox is observed in simple physical systems as well as transport networks.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ekd2MeDBV8s?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>The video (above) illustrates a system whereby a weight is suspended on two springs connected both in series (by an initially tense string) and in parallel (by initially slack strings). Removing the string which is in tension actually leads to the weight being lifted upwards.</p>
<p>This is actually a reverse of our traffic example. The distance the weight hangs represents the longer journey time of the traffic – remove the central string (the new road) and the hanging distance is reduced as is the journey time for the traffic.</p>
<h2>Paradox in action</h2>
<p>This paradox is not simply a mathematical quirk or one which can be neglected by network analysts. There are a number of examples where removing roads – rather than building news ones – has improved transport networks.</p>
<p>Probably the most famous example of this comes from South Korea. When the motorway network around Seoul <a href="http://www.theguardian.com/environment/2006/nov/01/society.travelsenvironmentalimpact">was reworked</a> to remove some of the 1960s-built roadways, the the result was significantly reduced transit times throughout the city. This was not because of fewer journeys through the city, rather a more efficient distribution of cars across the remaining network.</p>
<p>Similar phenomena have been observed during road closures in <a href="http://www.newscientist.com/article/mg22129520.600-42nd-st-paradox-cull-the-best-to-make-things-better.html">New York City</a> in the United States and in <a href="http://www.rockefeller.edu/labheads/cohenje/PDFs/175CohenKellyJApplProb1990.pdf">Stuttgart</a> in Germany.</p>
<h2>What does this mean for transport models?</h2>
<p>As Braess’s Paradox points out, even a slight change to a relatively unimportant part of the whole network can lead to massive changes in travel times. While planning reports might focus on headline stories – new road X will cut travel times by Y minutes – the underlying modelling must be more robust and look at the uncertainty around such estimates.</p>
<p>As painstaking as this modelling may be, it is unquestionably something that needs to be answered as fully and as correctly as possible, admitting its own limitations.</p>
<p>A multi-billion dollar infrastructure project cannot afford to fail simply because someone didn’t do their sums correctly. The financial consequences of incorrect projections can be financially catastrophic.</p>
<p>Both Sydney’s <a href="http://www.smh.com.au/business/cross-city-tunnel-facing-receivership-again-20130909-2tgsk.html">Cross City Tunnel</a> and <a href="http://www.smh.com.au/national/toll-of-misery-as-tunnel-goes-under-20100120-mlsn.html">Lane Cove Tunnel</a> drove their initial operators into receivership. The developers of Brisbane’s <a href="http://www.abc.net.au/news/2011-02-25/clem7-operator-placed-in-receivership/1958924">Clem Jones Tunnel fared no better</a>.</p>
<p>The issue is not just limited to Australia, of course. Of the <a href="https://books.google.com.au/books?id=RAV5P-50UjEC&pg=PA22&lpg=PA22&dq=channel+tunnel+15.9+million&source=bl&ots=RYwi397-hS&sig=iHDgMHpOATFO5gFrXh88a2dsJMw&hl=en&sa=X&ei=pOVXVbDRHM2C8gXyjoHAAw&ved=0CCMQ6AEwAQ#v=onepage&q=channel%20tunnel%2015.9%20million&f=false">15.9 million journeys expected</a> to be taken between London and Paris during the Channel Tunnel’s first year of operation, a mere 18% of those actually occurred.</p><img src="https://counter.theconversation.com/content/41684/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stephen Woodcock does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The planning for any new road should include plenty of mathematical modelling. But getting the right numbers can be a challenge and there’s the odd paradox to deal with as well.Stephen Woodcock, Lecturer in mathematics, University of Technology SydneyLicensed as Creative Commons – attribution, no derivatives.