Max Dorfman, Research Writer, Triple-I
Recreational marijuana use is associated with car crash trends, according to a paper published in Journal of Studies on Alcohol and Drugs. But the study also noted that the retail sale of marijuana is not solely responsible for the general increase in accidents.
Legalization of recreational marijuana use was correlated to a 6.5 percent increase in the number of crashes involving injuries and a 2.3 percent increase in those involving fatalities. With legalization and retail sales, the study found the overall effect was a 5.8 percent increase in accidents and a 4.1percent increase in fatalities.
But these results were inconsistent across states, with the effects on the number of accidents ranging from a 7 percent decrease to an 18 percent increase and the number of fatalities ranging from a 4 percent increase to a 10 percent decrease. Colorado experienced the largest increase in accidents after legalization and retail sales, at 17.8 percent. Nevada experienced the largest drop in fatal crashes, at 9.8 percent.
“Legalization removes the stigma of marijuana use, while the rise of retail sales only increases access,” said lead researcher Charles M. Farmer of the Insurance Institute for Highway Safety. “But access to marijuana isn’t difficult, even in non-retail locations. Users who previously avoided getting high may feel like it’s okay after legalization.”
Farmer added, “Studies looking for a direct causal link between marijuana use and crash risk have been inconclusive.” Unlike with alcohol, there is still no objective measure of how impaired a marijuana user has become.
As Triple-I notes, most studies find that marijuana use results in impaired coordination, memory, associative learning, attention, cognitive flexibility, and reaction time. Although it appears from this research that driving ability is impaired, the extent of the impairment continues to be studied.
Younger drivers are at higher risk of road traffic accidents than older drivers, with younger male drivers at high risk. Early evidence suggests that younger male drivers are most likely to drive under the influence of marijuana.
Another study, in the journal drug and alcohol addiction, suggests that chronic, heavy use of recreational marijuana impairs driving performance, even when the driver is not high, with those who began regular marijuana use before age 16 showing the worst outcomes.
These results show that the effects of marijuana vary greatly between demographic groups, making it all the more important for everyone to be careful when using the drug.