It's also not safe to drive while tired, on any medication at all (including over the counter drugs), while texting, while on the phone, while not looking at the road, with glasses (they could fall off and you'd be blind), with a heart condition, etc etc.
I think it's safe to assume you drive very often with things that affect your driving. If pot is proven to not affect your driving to a measurable degree, then the only thing that is different between that and random over the counter medication is one is called pot.
I think it's safe to assume you drive very often with things that affect your driving. If pot is proven to not affect your driving to a measurable degree, then the only thing that is different between that and random over the counter medication is one is called pot.