Driving high on weed is a tricky subject and a central issue to many debates about legalization throughout the country. For starters, there’s no standard for impairment: Just because a driver might be under the influence of cannabis does not necessarily mean they’re too intoxicated to drive. Moreover, the roadside options for measuring impairment are still in development, if not also few and far between.
Recently, the California Highway Patrol (CHP) debuted a device that measures active THC content in a driver’s saliva. Developed by Alere Toxicology in Santa Rosa, California, the device takes the form of a plastic swab stick that goes into a small computerized unit. It’s used only in three counties so far: Sacramento, Los Angeles, and Kern.
The $6,000 device has a 95 percent accuracy rate, according to a spokesperson with Alere Toxicology, and tests for cannabis, as well as cocaine, methamphetamine, opiates, and other substances. The CHP’s eventual goal is to use the device statewide.
Since the device tests for active THC, and not metabolites, it provides a more accurate picture of how recently the driver consumed cannabis. Other drug tests, such as a blood test, measure inactive metabolites, which can remain in a person’s system up to a month after use, and so doesn’t give an accurate sense of how intoxicated the driver might have been when they were pulled over. Still, there’s no threshold for how many nanograms of THC in someone’s system constitute impairment; other factors like tolerance also have an effect.
According to a report by the Canadian Drug Policy Coalition, while there are no hard statistics on how many people overall smoke and drive, roadside studies show that about four to six percent of drivers have used cannabis within two hours of driving. Other self-reported population surveys have also shown that about 20 percent of people who use cannabis drive within two hours of consumption. However, yet another study indicated that 79 percent of cannabis users said they had never driven within that two hour time frame.
The report also indicated that high schoolers, men, and frequent cannabis users are more likely to use cannabis and drive than other people are. However, that doesn’t necessarily mean they are more prone to getting into an accident — again, it depends on how intoxicated they are and what their tolerance to THC is. More than 50 percent of of cannabis users think that using cannabis won’t increase their chances of getting into an accident, according to the report. One study showed that the odds of getting into a cannabis related accident are 1.22 times more likely, while for an alcohol related accident, the odds are two to four times more likely.
It’s debatable whether cannabis makes you a better or worse driver. Some find themselves driving more slowly, while more alert and conscience of the road; however, others may find their motor coordination and reaction time compromised.
In general, the higher you get, it’s less of a good idea to get behind the wheel of a car.