Legalizing recreational marijuana use in Colorado, Oregon and Washington has resulted in more collision claims, according to a new Highway Loss Data Institute (HLDI) report.
The HLDI analysis indicates that collision claim frequencies are about 3 percent higher overall than would have been expected without legalization.
The report, HLDI’s first on how marijuana legalization since 2014 has affected crashes reported to insurers, found that more drivers admit to using marijuana, and that it is showing up more frequently among people involved in crashes.
Retail sales of recreational marijuana to adults over 21 began in Colorado in January 2014, in Washington in July 2014 and in Oregon in October 2015.
HLDI conducted a combined analysis using neighboring states as additional controls to examine the collision claims experience of Colorado, Oregon and Washington before and after law changes. Control states included Idaho, Montana, Nevada, Utah and Wyoming, plus Colorado, Oregon and Washington prior to legalization of recreational use.
During the study period, Nevada and Montana permitted medical use of marijuana, Wyoming and Utah allowed only limited use for medical purposes, and Idaho didn’t permit any use. Oregon and Washington authorized medical marijuana use in 1998, and Colorado authorized it in 2000.
“The combined-state analysis shows that the first three states to legalize recreational marijuana have experienced more crashes,” said Matt Moore, senior vice president of HLDI. “The individual state analyses suggest that the size of the effect varies by state.”
Colorado saw the biggest estimated increase in claim frequency compared with its control states. After retail marijuana sales began in Colorado, the increase in collision claim frequency was 14 percent higher than in neighboring Nebraska, Utah and Wyoming. Washington’s estimated increase in claim frequency was 6 percent higher than in Montana and Idaho, and Oregon’s estimated increase in claim frequency was 4 percent higher than in Idaho, Montana and Nevada.
“The combined effect for the three states was smaller but still significant at 3 percent,” Moore said. “The combined analysis uses a bigger control group and is a good representation of the effect of marijuana legalization overall. The single-state analyses show how the effect differs by state.”
