Marijuana legalization appears to increase the rate of traffic accidents, but it doesn’t necessarily mean there will be more deadly crashes.

Those are the conclusions of two separate studies published last week about one of the biggest unresolved questions in states such as Maine that have legalized pot: Will more people get behind the wheel when they shouldn’t, and how much damage will impaired drivers do?

The two conflicting studies add to the debate and confusion over the issue of impaired driving in Maine, where lawmakers, police and advocates have grappled with the best ways to prevent stoned drivers from getting behind the wheel and punish the ones who do.

Legalization advocates and people who opposed the initiative in Maine agree the studies draw valuable attention to the issue and help highlight the importance of keeping impaired drivers off the road, but they disagree on the accuracy of the studies’ conclusions.

“The takeaway needs to be that we all agree people should not use marijuana and drive,” said David Boyer, Maine political director for the Marijuana Policy Project, which supported Maine’s legalization law.

The Highway Loss Data Institute, a leading insurance research group, said in a study released Thursday that collision claims in Colorado, Washington and Oregon increased 2.7 percent in the years since legal marijuana sales began, compared with surrounding states without recreational marijuana laws.

A study published Thursday in the American Journal of Public Health concluded that after three years of recreational marijuana legalization, changes in motor vehicle crash fatality rates for Colorado and Washington were not statistically different from those in similar states without legal pot. Authors also reported no association between marijuana legalization and the total number of non-fatal crashes.

Those studies join a handful of others released over the past two years that look at the impact of marijuana on traffic accidents since Colorado started legal pot sales in 2014. With relatively limited data to work with, the studies can be confusing and provide vastly different views of the role marijuana plays in traffic accidents.

“People take from the studies what they want to hear,” said Chief Edward Googins of the South Portland Police Department, adding that he believes the most valuable studies look at the causes of collisions rather than the severity alone.

The Highway Loss Data Institute says its study examined claims from January 2012 to October 2016. Researchers accounted for factors such as the number of vehicles on the road, age and gender of drivers, weather and whether the driver making the claim was employed. Neighboring states with similar fluctuations in claims were used in comparison.

Marijuana legalization advocates question the results of the study and the comparison of rural states like Wyoming and Montana to states with dense population centers, such as Colorado and Washington.

“They didn’t look to see the actual causes of the collision and it doesn’t show that marijuana is to blame for the increases they found,” Boyer said. “It seemed to produce more questions than answers.”

But for Googins and York County Sheriff Bill King, the Highway Loss Data Institute study illustrates a problem they saw coming even before Maine became one of eight states with an adult-use marijuana market.

“From the get-go, one of the primary concerns for law enforcement in Maine was that (marijuana) is going to impact our traffic crashes and safety on the roads,” Googins said. “When you add another substance, how can you say it’s not going to cause an increase? The studies reinforce that logic.”

Googins said drivers getting behind the wheel while impaired by marijuana continues to be a concern for police in Maine because there is no simple roadside test like a Breathalyzer to test for impairment. His department has three drug recognition experts who are trained to spot signs of impairment by various drugs, but many departments don’t have someone with that training on staff or on duty at all times.

King said impaired driving is especially troubling for him because York County leads the state in fatal car crashes. As more adults use marijuana now that it is legal, he believes his deputies will have to deal with more crashes.

“We’re gearing up for it,” he said. “It’s a concern for me because in our county there are a lot of rural, windy roads where you need to have all of your faculties.”

Boyer, from the Marijuana Policy Project, said driving while impaired by any substance is already illegal and “if you can’t walk the straight line, you should have the book thrown at you.” But as the country goes in the direction of legalization, there needs to be more public education about not consuming marijuana before driving, he said, suggesting the cannabis industry needs to take an active role in that.

Scott Gagnon, chairman of Smart Approaches to Marijuana Maine, agrees that education is important and said prevention coalitions in Maine are already working to educate people on the local level. Gagnon said driving and marijuana is a frequent topic at meetings he holds with community groups.

Gagnon said it is important for lawmakers to keep an eye on whether Maine sees the same increase in accidents highlighted in the Highway Loss Data Institute study.

“It speaks to why we need to have strict regulations in place to minimize impaired driving,” Gagnon said. “We have one shot at this.”

Gillian Graham can be contacted at 791-6315 or at:

ggraham@pressherald.com

Twitter: grahamgillian