The movement to legalize marijuana in several states has led many to speculate about a potential rise in the number of car accidents caused by impaired driving. Most states have impaired driving statutes that tie some level of the active drug in marijuana, THC, to an automatic finding of impairment. But studies have been inconclusive about a definitive connection between concentrations of THC and impairment. Some even question whether marijuana has any impact on a person’s ability to drive a car safely. A recent study supports the notion that marijuana is far less dangerous than alcohol in terms of driving safety.
The National Highway Traffic Safety Administration conducted a study of 9,000 drivers and their safety records over a 20 month period. Among those 9,000, the drivers who were regular marijuana users suffered elevated car accident rates. In fact, regular marijuana users were involved in accidents 25 percent more than non-marijuana users. That was not the end of the story, however.
In looking specifically at the subset of marijuana users, the study corrected for other factors, including age, the presence of alcohol and the gender of the driver. Those factors were all found to be more important the use of marijuana. After they were factored out, marijuana use had virtually no impact on crash rates. Basically, the correlation between marijuana use and a known risk factor, such as alcohol abuse, made it appear as though marijuana led to unsafe driving.
It is not necessarily enough to say that marijuana does not directly cause a driver to be less safe. A sound safety policy requires a holistic look at the impact of marijuana use on driver behavior. The point is not to punish people for life choices, but to make the roads safer for everyone and make sure fewer people are injured or killed in traffic accidents.
Source: United Press International, “NHTSA: Marijuana use may not significantly increase traffic accidents,” by Thor Benson, 7 February 2015