Half of cannabis users think they can drive safely while high – are they right?

It's been several years since recreational cannabis was made legal in some US states. What effect has it had on road safety?

People who are stoned often think they're being funnier than they actually are, now we know they overestimate their driving ability too.

Almost half of cannabis users believe it's safe to drive when you're high, according to a new study by PSB Research and Buzzfeed News. Perhaps unsurprisingly, those who abstain from weed, take a different view - only 14% believe someone who's stoned can drive safely.