When it comes to the debate over the correlation between legal marijuana and an increased danger in driving, June provided two very different takes on the topic.

An American Journal of Public Health (AJPH) study found that the legalization of adult-use marijuana in Colorado and Washington led to no increase in motor vehicle fatalities when compared to eight “control states” where marijuana is not legal.

This came on the heels of an AJPH study from earlier this year that found traffic fatalities had actually decreased in states where medical marijuana is legal.

Marijuana – Driving More Hazardous Now?

On the flip side came a study from the Highway Loss Data Institute, which found the number of car insurance collision claims went up in Colorado, Oregon and Washington after recreational marijuana was legalized in those states.

Increased Danger

Of course, one study focused on fatalities, the other on collisions. Still, they paint a very different picture of the hazards that legalized marijuana brings for drivers.

The Highway Loss Data Institute looked at data from Colorado, Oregon and Washington, using numbers from neighboring states as a control. They looked at crash collision claims filed between January 2012 and October 2016.

They found the states where adult-use marijuana is legal had a 3 percent higher number of crashes than those in neighboring states. Colorado had the highest number, at 14 percent.

The findings led David Zuby, executive vice president and chief research office at the Insurance Institute for Highway Safety, to say that “worry that legalized marijuana is increasing crash rates isn’t misplaced.” He said the report should give “pause” to other states considering legalization.

Or Maybe Not

The AJPH study found no connection to marijuana legalization and dangerous driving, at least when it comes to the issue of traffic fatalities.

According to the research, the pre-legalization traffic fatality rates in Colorado and Washington were similar to those in eight control states where marijuana is not legal for recreational use. After legalization, the numbers did not alter significantly.

The study concluded that three years after legalization, traffic fatality rates in Colorado and Washington had not changed, leading to the conclusion that adult-use marijuana legalization has not to date led to more deaths in car accidents.

As noted, an earlier AJPH study found that traffic fatalities dropped, on average, in states where medical marijuana is legal. However, only 7 of the states experienced actual reductions in traffic fatalities during this time.

The lesson for marijuana users: Never drive under the influence, no matter what any study says.

The lesson for researchers: As noted by the AJPH, “Future studies over a longer time remain warranted.”