AURORA | Drivers with any amount of marijuana in their system during a crash that killed someone rose between 2009 and 2011, a new study from the University of Colorado reports.
According to the study, which compared Colorado drivers with drivers from 34 other states without medicinal marijuana, the percentage of drivers in fatal crashes with marijuana in their system more than doubled from 4.5 percent in 1994 to 11 percent in 2011. The study doesn’t imply that marijuana was a factor in causing the crashes, only that it was present in the driver’s bloodstream.
“It may very well be that marijuana was just more available,” said the lead author of the study Stacy Salomonsen-Sautel, a postdoctoral fellow at the University of Colorado School of Medicine Department of Pharmacology.
The study was conducted using National Highway Traffic Safety Administration data and data from the separate states themselves. There was no threshold for the amount of marijuana found in the driver’s system. Only a small percentage of the drivers were found to have both alcohol and marijuana present in their bloodstreams.
Salomonsen-Sautel said the proportion of drunk drivers involved in fatal crashes remained relatively flat during the same time period, while there was a “huge increase” in the number of drivers with marijuana in their systems.
The number of fatal crashes in Colorado has decreased every year since 2002, she said.
“What this really shows is that there just may be an increase in the number of people driving with marijuana in their system,” she said.
The study was meant to raise awareness for better eduction and prevention programs to curb impaired driving, according to the University of Colorado School of Medicine.
Dr. Christian Hopfer, associate professor of psychiatry, was the senior author of the study. Sung-Joon Min and Drs. Joseph Sakai and Christian Thurstone contributed research to the study. The study was funded by the National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism.
This study says nothing of culpability. Of course if there is an increase in cannabis usage in the general population there will be a corresponding increase in detectable metabolite levels in drivers. IE, if 10% of the population is regularly using cannabis, then if it has little effect on crash risk, we would expect to find about 10% of drivers to test positive given its detectability for days. This study was funded by the NIDA btw.
Oh and there is this:
“From 2006 to 2011, traffic fatalities decreased in Colorado 16 percent”
The Legalization of Marijuana in Colorado: The Impact. Rocky Mountain HIDTA. 2013.