Number of Fatal Crashes Involving Marijuana Triples

person smoking joint

Just as the movement to legalize marijuana appears to have gained ground, a new study shows that fatal car crashes involving the use of marijuana have tripled.

Researchers from Columbia University’s Mailman School of Public Health gathered data over a 10-year period, from 1999 to 2010, from six states — California, Hawaii, Illinois, New Hampshire, Rhode Island, and West Virginia. The states were chosen because they routinely perform toxicology tests on drivers who are killed as a result of motor vehicle collisions. The researchers analyzed data from more than 23,500 drivers who died within one hour of a fatal collision. The results indicate that one in nine drivers killed in fatal crashes tested positive for marijuana..

As you would expect, alcohol remains a significant factor in motor vehicle accidents, playing a role in about 40 percent of all fatal accidents in the Columbia study, according to a report about the research by CBS Seattle. However, marijuana played a bigger role than you might expect. Drugged driving in general appears to be on the rise, with more than 28 percent of drivers in the study testing positive for some type of drug in 2010 compared with just 12 percent in 1999.

While drugged driving overall appears to have increased, marijuana represents the biggest increase. Marijuana contributed to 4 percent of the fatalities in 1999 but was a factor in 12 percent by 2010.

Drugged driving is of enough concern that it has made the National Transportation Safety Board’s “Top Ten List” for the past two years in a row. The list includes areas where the NTSB would most like to see safety improvements over the next year.

According to Jonathan Adkins, deputy executive director of the Governors Highway Safety Association, marijuana impairs driving in much the same way that alcohol does.

The Columbia study highlights the dangers of mixing drunk driving with drugged driving. A driver who is under the influence of alcohol has a risk of a fatal crash that is 13 times higher than that of a driver who is sober. A driver who is under the influence of both alcohol and marijuana has a risk of a fatal crash that is 24 times that of a sober person.

A number of states have legalized medical marijuana. However, having a prescription that allows you to legally use marijuana does not exonerate you from a charge of driving under the influence. Alcohol is legal, but driving while under the influence of alcohol is not legal. Similarly, driving under the influence of marijuana is illegal, even in states that allow its use for recreational or medicinal purposes.