A favorite citation used by the marijuana lobby to promote the idea that marijuana doesn’t impair driving is one published in 2015 by the National Highway Traffic Safety Administration (www.nhtsa.gov/behavioral-research/drug-and-alcohol-crash-risk-study). And when the study is cited, the results are usually badly misquoted.
Los Angeles Times: “Good news (?): marijuana doesn’t increase the likelihood of car crashes.”
USA Today: “New study shows no link between marijuana use and car accidents.”
Reason: “Landmark study finds marijuana … READ MORE
Two articles on the effect of recreational marijuana commercialization on traffic fatalities reached opposite conclusions in the June 22nd 2020 issue of JAMA Internal Medicine. Readers should understand the effect of study design differences before concluding that marijuana can be commercialized without an increase in traffic fatalities.
Jeff Brubacher from Vancouver General Hospital published “Cannabis use as a risk factor for causing motor vehicle crashes: a prospective study.” The study has earned a great deal of press due to his finding that there was no increased risk of crash responsibility in the driver pool he studied for drivers with a blood THC level between 2 and 5 ng/ml. There was an increased risk of crash responsibility for drivers over 5 ng/ml, but … 
What has marijuana legalization done to Driving Under the Influence (DUI) cases in Colorado? Important answers are now emerging. July 2018, the Division of Criminal Justice (DCJ) released a 106-page report 
Jacob Sullum, a pro-pot writer for Reason and Fortune magazines, is at it