Study: drivers in states where cannabis is legal less likely to drive under the influence

The driver study was carried out by researchers from the Center for Health, Analytics, Media and Policy, RTI International and’Office of Research Protection in Research Triangle Park, North Carolina. It was published online on April 23 and will be published in Preventive Medicine Reports in June 2022.

The study analyzed the consumption behaviors of 1,249 people. More than a third of participants reported driving under the influence within three hours of use in the past 30 days, and another third shared their cannabis use within 20 or more days over a 30-day period.

«Current cannabis consumers in the States where cannabis is used for recreational and medical purposes were significantly less likely to report driving within three hours of using in the past 30 days, compared with current users living in states without legal cannabis,» the researchers write. «The only exception was frequent cannabis users who lived in states where cannabis is allowed for medical purposes only. Their risk of DUIC [driving under the influence of cannabis] did not differ significantly from that of frequent users living in states without legal cannabis.»

The researchers suggested a solution to combat driving under the influence of cannabis, which should be specifically targeted at states without legal cannabis programs. «Our results suggest that prevention of driving under the influence is most needed in states without cannabis legalization. Since regulation of cannabis products in non-legal environments is not possible, mass media campaigns may be a good option for providing DUIC education.»

Overall, the researchers concluded that education campaigns could help continue to prevent people from driving immediately after using cannabis. «Although all states should educate its citizens about the potential dangers of cannabis use and driving, this analysis suggests that states without legal cannabis are particularly in need of DUIC prevention efforts,» they wrote. «States should consider mass media campaigns to educate all cannabis users, including the most frequent, about the dangers of DUIC. Medical states may consider targeting frequent users by disseminating DUIC information through medical dispensaries.»

L’study also shared that it found three other studies pointing in the same direction. Two were shared in 2020, and one was published in 2021, with different levels of approach regarding the analysis of the effect of legalizing recreational and/or medical cannabis.

States like Massachusetts are gearing up to strengthen enforcement of driving-under-the-influence laws. Governor Charlie Baker announced legislation in November 2021 that will «provide law enforcement officers with more rigorous drug detection training and strengthen the legal process by allowing courts to recognize that the active ingredient in marijuana can and does impair motorists.» However, Baker's legislation does not address how to approach the measure of impairment or properly determine whether a person has recently used cannabis and is impaired, or has used it several days or weeks prior to an incident and is no longer impaired.

A recent study published in Canada expresses the need for a better way to accurately detect impairment. «We'd love to have a single measure that would let us know whether or not that person is impaired,» said lead author Sarah Windle. «But unfortunately, in the case of cannabis, it's just not that simple».