According to new research published in Accident Analysis & Prevention entitled “Drug use and fatal motor vehicle crashes: A case-control study,” detection of cannabis was the least likely predictor of fatal automobile crashes when compared to other drugs and especially alcohol.
Dr. Guohua Li, lead author of the study said, “I would say, even though there are risks associated with the use of marijuana, it seems to be not as big as other drugs like depressants, stimulants and other narcotics.”
By studying the cases of 737 drivers from 2007 involved in fatal wrecks, Dr. Li and colleagues compared crash rates to determine an “odds ratio”. As a baseline, drivers with no drugs and no alcohol in their system are considered to have a 1:1 odds ratio and Dr. Li calculated how much more likely a drugged driver would be in a fatal crash compared to these baseline sober drivers.
Drivers who tested positive for cannabis (detected either as actual THC in blood or THC-COOH metabolites in saliva) were found to have a 1.81:1 odds ratio – meaning about an 81% greater chance of a fatal accident.
But the odds ratios for commonly prescribed medications make cannabis’ risks look tame. Narcotics such as Oxycontin, Vicodin, and Dilaudid came in with a 3.03:1 – triple the risk of fatal crash. Stimulants like Adderall, Ritalin, and Phentermine have a 3.57:1 odds ratio. Depressants like Ativan, Valium, and Klonopin registered a 4.83:1 risk. Yet many of these medications carry the warning “Until you know how this medication may affect you, don’t drive or operate heavy machinery.” Once you do know the effects, apparently we trust you to manage the risk.
The greatest single drug risk, of course, is the legal one you don’t need a prescription for, alcohol. Its odds ratio, absent any other drug in the driver’s system, was a whopping 13.64:1. This risk was even worse than drivers with multiple drugs in their system (3.41:1). Yet we accept that drivers with less than 0.08 blood-alcohol content may be able to drive safely enough for us to legally tolerate.
This is not to say you should pull massive bong rips and get behind the wheel – it is never responsible to drive while impaired. And drinking plus toking is the worst risk of all, coming in at a 23.24:1 odds ratio. But considering how much risk we allow adults to manage with much more dangerous drugs and alcohol, it is time we reject alarmist anti-stoned driving legislation that ignores science.