The Prevalence of Marijuana in Suspected Impaired Driving Cases in Washington State†

Drugged driving is a safety issue of increasing public concern. Using data from the Fatality Analysis Reporting System for 1999-2010, we assessed trends in alcohol and other drugs detected in drivers who were killed within 1 hour of a motor vehicle crash in 6 US states (California, Hawaii, Illinois, New Hampshire, Rhode Island, and West Virginia) that routinely performed toxicological testing on drivers involved in such crashes. Of the 23,591 drivers studied, 39.7% tested positive for alcohol and 24.8% for other drugs. During the study period, the prevalence of positive results for nonalcohol drugs rose from 16.6% in 1999 to 28.3% in 2010 (Z = -10.19, P < 0.0001), whereas the prevalence of positive results for alcohol remained stable. The most commonly detected nonalcohol drug was cannabinol, the prevalence of which increased from 4.2% in 1999 to 12.2% in 2010 (Z = -13.63, P < 0.0001). The increase in the prevalence of nonalcohol drugs was observed in all age groups and both sexes. These results indicate that nonalcohol drugs, particularly marijuana, are increasingly detected in fatally injured drivers.

To characterize drug prevalence among fatally injured drivers, identify significant associations (i.e. day of week, time of day, age, gender), and compare findings with those for alcohol.