National data on the effects of marijuana use on road ... number of Americans acknowledge that they are driving after consuming marijuana. An estimated 14.8 million motorists said that they ...

Magia pointed out that traces of THC, the active ingredient in the drug, may remain in the blood for as long as 80 hours after the person smoked marijuana or otherwise consumed cannabis.

Ohio State Highway Patrol said this is part of a pilot program, and it's not being done in response to the legalization of recreational marijuana.

As marijuana becomes more normalized in American culture, its effects on impaired driving and public safety will also be amplified. Marijuana is known to impair balance, coordination and judgement ...

So, regarding marijuana DUI, California state can take similar actions as driving under the influence of alcohol ... as THC can stay in a person’s system long after the effects of the drug have worn ...