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Roadway deaths involving cannabis on the rise: study

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Boston — The percentage of roadway fatalities involving cannabis or a combination of cannabis and alcohol more than doubled over a recent 19-year period, results of a recent study show.

Using 2000-2018 data from the National Highway Traffic Safety Administration’s Fatality Analysis Reporting System, researchers from the Boston Medical Center, Boston University and the University of Victoria looked at roadway fatalities in which the driver tested positive for a cannabinoid and/or had any amount of alcohol in their system.

The proportion of cannabis-related crash fatalities increased to 21.5% in 2018 from 9% in 2000. The percentage of fatal crashes involving both alcohol and cannabis jumped to 10.3 in 2018 from 4.8 in 2000. Additionally, people who died in crashes involving cannabis were 50% more likely to have alcohol in their system.

The researchers say the results suggest that as states have relaxed cannabis laws, alcohol and cannabis have been used together increasingly among impaired drivers.

The proportion of motor vehicle-related deaths involving alcohol remained relatively unchanged over the 19-year study period. According to a Boston Medical Center press release, more than 40% of U.S. roadway deaths involve alcohol, while 30% involve a blood alcohol content above the legal limit for driving.


“There has been progress in reducing deaths from alcohol-impaired driving, but our study suggests that cannabis involvement might be undercutting these public health efforts,” senior study author Timothy Naimi, a physician and adjunct professor at BU, said in the release.

According to lead study author Marlene Lipa, an epidemiologist at the medical center, testing methods for cannabis “remain suboptimal, and individuals can test positive weeks after they have consumed it.”

She adds: “The bottom line is that we have a lot of work to do to reduce deaths and harms from impaired driving from alcohol, cannabis and other substances.”

The study was published online in the American Journal of Public Health.

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