A new report from the University of Minnesota sheds light on how many Minnesotans are using marijuana and driving.
Researchers surveyed more than 2,300 adults at the Minnesota State Fair and a number of Minnesota county fairs in 2024 and 2025. The Minnesota Legislature formally legalized the sale of hemp-derived THC edible and beverage products in 2022.
"Specifically we asked them about whether they use cannabis while or just before driving a car," says Colin Planalp, one of the study's authors from the University's Cannabis Research Center.
He says the behavior was most commonly reported among younger respondents. But older adults tended to use it more often.
"20% or so said they did it once a day or more, and another 17% said they did it once a week or more," Planalp explains. "Meanwhile, about 47% said they only did it once or a few times a year."
Among respondents who reported using cannabis, 15.7% said they had used cannabis while, or just before, driving in the past year.
"Almost 30% of respondents aged 18 to 20 years old said that they had used cannabis and driven in the past year," Planalp adds. "That is especially notable."
Notable because under Minnesota law, driving while impaired is illegal, whether the impairment is caused by alcohol, cannabis or other substances. Studies have found evidence that cannabis can harm a person’s ability to drive, such as by slowing reaction time.
While there is no legal limit like with alcohol and the 0.08 BAC (Blood Alcohol Content) restriction, law enforcement can arrest a driver for DWI if they observe and document impairment. There currently is no way to legally test for impairment for cannabis use, like a breathalyzer for alcohol.
The Minnesota Department of Public Safety conducted a pilot project in 2024 on two oral fluid roadside testing instruments. The goal is to obtain legislative approval to use an oral fluid roadside testing instrument in the field.
State law also places other restrictions on cannabis possession and use related to motor vehicles. People under age of 21 are prohibited from possessing or using any cannabis while operating a motor vehicle, regardless of whether they are impaired, and placed limits on the amount of cannabis that a person of legal age can possess, whether in a motor vehicle or elsewhere in public.
