More places, including Canada, are legalizing cannabis, but how do we figure out when it's no longer safe to drive?
Why do tech companies care so much about self-driving cars? If drivers no longer need to pay attention to the road, they can use their mobile devices even more.
There's a strong case for governments to allow cannabis producers to brand their products via packaging and advertising like any other product. It could boost quality and consumer satisfaction.
The science is still hazy - but our abilities are clearly affected during the recovery period.
Research suggests lower blood alcohol concentration limits and interventions like ignition interlocks can make a big difference.