31.9 percent of drivers involved in fatal crashes test positive for drugs.
The good news for us pot-crazed Angelenos? Of all the drugs authorities have detected in these cases, marijuana seems to be the one that turned up the least, according to a new study conducted by Columbia University's Mailman School of Public Health:
The bad players in car crashes are depressants, stimulants, and narcotics, followed by Mary Jane, according to the study published in the journal Accident Analysis and Prevention.
Researchers looked at federally funded data from the 2007 National Roadside Survey of Alcohol and from the Drug Use by Drivers and the Fatality Analysis Reporting System. They concluded this in a summary:
The estimated odds ratios of fatal crash involvement associated with specific drug categories were 1.83 for marijuana, 3.03 for narcotics, 3.57 for stimulants, and 4.83 for depressants.
But: Put alcohol in the mix, and things get dicey. Alcohol was found in 57 percent of driver involved in fatal crashes. Alcohol and drugs together were a factor in 1 in 5 crashes.
... Drug use is associated with a significantly increased risk of fatal crash involvement, particularly when used in combination with alcohol.
Columbia professor of epidemiology Guohua Li, who led the study, saved much of his ire for prescription drugs:
While alcohol-impaired driving remains the greatest threat to traffic safety, these findings about drugged driving are particularly salient in light of the increases in the availability of prescription stimulants and opioids over the past decade.