This study is complete horseshit, a more accurate title is “Car crash deaths involving people who may have consumed cannabis in the past month are on the rise”
Are total car crashes on the rise ? How does that figure compare to the amount of cars on the road ?
But they were up the last two years: https://en.wikipedia.org/wiki/Motor_vehicle_fatality_rate_in...
As far as why, this article might shed some light: https://www.vox.com/22675358/us-car-deaths-year-traffic-covi...
"According to several traffic experts I spoke with, the explanation for the 2020 fatality spike is relatively straightforward: With fewer cars on the road during quarantine, traffic congestion was all but eliminated, which emboldened people to drive at lethal speeds. Compared to 2019, many more drivers involved in fatal crashes also didn’t wear seat belts or drove drunk."