Marijuana legalization has been linked to increased traffic collisions in a new study released by the Insurance Information Institute.

The study, A rocky road so far: Recreational marijuana and impaired driving, examines the impact marijuana legalization has had on road safety.

More than 30 states, the District of Columbia, Guam and Puerto Rico have programs that allow qualifying patients to access medical marijuana products. Another 13 states permit non-intoxicating medical marijuana products. Ten states and D.C. permit recreational marijuana, where any adult over the age of 21 can possess and use the drug.

With concerns increasing about the impact of marijuana legalization on road safety, the report examines the current state of knowledge related to marijuana impairment, its effects on driving abilities and how states are grappling with the issue of “stoned driving”.

View the report on the Insurance Information Institute website.