Study Finds Safer Roads Are a Side Effect of Medical Marijuana Laws

States that have legalized medical marijuana have fewer fatal car accidents, according to a new study by the Institute for the Study of Labor.

The study looked at traffic fatalities from 1990 to 2009 and concluded that there were 9 percent fewer traffic fatalities in the 13 states that have legalized marijuana. One reason is that people are trading 6 packs for spliffs: beer sales dropped off 5 percent in the states where medical pot is legal. And it turns out that the switch makes our roads safer.

The researchers looked into how smoking pot affects drivers and found that having more stoners on the road is probably better than drunks. Yeah, pot affects drivers' reaction time, perception of distance and hand-eye coordination, like alcohol. But stoned drivers tend to slow down, leave a lot of space between him and the car ahead and they don't try to do anything too crazy. Drunk drivers have all the same issues as stoned drivers, but they drive fast, are overconfident about their ability and like taking risks. They crash more.

But there might be another more obvious reason medical marijuana is making our roads safer. People who are opting to smoke instead of drink are probably at home eating Cheetos and watching Dr. Who reruns, while people who are drinking are more likely to be out at bars. It's the ride home that's killing the 20-29-year-old set.

"Traffic fatalities are an important outcome from a policy perspective because they represent the leading cause of death among Americans ages five to 34," said economics professor Daniel Rees, who conducted the study. “Although we make no policy recommendations, it certainly appears as though medical marijuana laws are making our highways safer."