With more than 100 recreational and 500 medical marijuana stores open for business in Colorado, stoned drivers are a growing concern. As a result, the state is stepping up education and enforcement, says NPR. Sean McAllister, a Denver criminal defense attorney, gets five calls a week from clients with pot DUI citations. Users don’t have guideposts for marijuana impairment, he says. Is half a joint too much? What about two or five bong rips? No one is sure.
It doesn’t help that marijuana doesn’t metabolize predictably like alcohol, says John Lacey, a traffic safety expert based in Maryland. “It makes setting an absolute level where everyone is impaired, like we have for alcohol, much more difficult for marijuana and for other drugs,” Lacey says. “They just behave differently than alcohol does.” And drivers behave differently on marijuana than after drinking. They drive slower, but they also have trouble staying in their lane and lack a quick response time. Lacey says it’s best to stay off the road. Some studies indicate that stoned drivers are 33 percent more likely than sober drivers to be involved in a fatal crash. That’s enough of a risk to prompt a new state educational campaign.