The percentage of drivers involved in fatal traffic crashes who had the active ingredient in marijuana in their blood has more than doubled since recreational marijuana became legal in Washington, according to newly released estimates.
Between 2008 and 2012, the five years before Washington legalized marijuana, an estimated 8.8 percent of Washington drivers involved in fatal crashes were positive for tetrahydrocannabinol, the compound in marijuana that makes users high.
That percent increased to 18 percent for the five years after the drug became legal in December 2012. For 2017, the final year covered by the study, an estimated 21.4 percent of Washington drivers involved in fatal crashes were THC positive, the highest percentage during the 10 years examined.
“This study enabled us to review a full 10 years’ worth of data about the potential impact of marijuana on driving safety, and it raises significant concerns,” David Yang, executive director of the AAA Foundation for Traffic Safety, said in a statement. “Results from the analysis suggest that legalization of recreational use of marijuana may increase the rate of THC-positive drivers involved in fatal crashes.”