Mental Health Center

Marijuana Raises Risk of Fatal Car Crash

Dec. 1, 2005 - People who drive after using marijuana are nearly twice as likely to be involved in a fatal car crash.

French researchers studied all drivers involved in fatal car crashes over a two-year period and found 7% tested positive for marijuana, including nearly 3% who tested positive for a combination of marijuana and alcohol.

Although marijuana's share of fatal crashes is much lower than those attributed to alcohol, researchers say the results show that marijuana use, even in low doses, significantly increases the risk of fatal car accidents.

More Pot, More Deaths

In the study, published in the medical journal BMJ, researchers reviewed information on 10,748 drivers who were involved in fatal car crashes and took required tests for drugs and alcohol.

Twice as many drivers involved in fatal car accidents tested positive for marijuana compared with a group of other drivers.

Researchers say about 2.5% of the fatal crashes were attributable to marijuana compared with nearly 29% attributable to alcohol.

The study also showed that drivers who tested positive for marijuana were more than three times as likely to be responsible for the fatal car crash. Researchers say the likelihood of being at fault increased as the blood concentration of marijuana increased.