There’s a lot to be said for states that have legalized recreational and/or medical cannabis, but even Colorado and Washington have one problem – arbitrary blood-THC limits which imply a driver is impaired.
These numbers, such as Washington’s 5ng/ml, have no scientific basis for assessing the level of impairment. Despite this, six states with legal weed have per se limits for tetrahydrocannabinol; being over that number automatically makes you guilty of driving under the influence of drugs (DUID).
Oregon, however, is bucking the trend. In its DUI Legislative Report, the state’s Liquor Control Commission said it is recommending against a per se THC limit. By relying on the actual state of science, this welcome exercise in rationality should set an example for other states setting up their own regulatory framework.
Oregon’s Liquor Control Commission was tasked in 2015 with “regulating the recreational marijuana market in Oregon, with studying the question of THC-related intoxicated driving.”
Due to restrictions on cannabis research and limited data, it is difficult to make definitive statements about the risk of THC-intoxicated driving. The body of evidence that does exist indicates that while attitudes towards driving after marijuana use are considerably more relaxed than in the case of alcohol, the risk of crashes while driving under the influence of THC is lower than drunk driving. Little evidence exists to compel a significant change in status quo policy or institute a per se intoxication standard for THC.”
A widely-reported study by the American Automobile Association in 2016 found no scientific basis for blood-THC limits and called on the six states using such laws to abandon them. Chemical tests for THC have not been shown to correlate to things like brake and gas pedal coordination, distance perception and general attention.
The only thing we know about blood-THC and driving is that it is not comparable to the tests for alcohol impairment. There is no THC breathalyzer test, and urine tests cannot detect it. Some blood tests can distinguish between THC and its longer-lasting metabolites, but these levels can vary widely depending on how often the person uses cannabis. Test results will also vary based on whether one smoked or ate the cannabis.
One person can feel impaired at 5ng/ml while another can function with no detectable impairment. In fact, many people charged with DUID based on arbitrary blood-THC limits have convinced juries they were not impaired when they were pulled over.
Even so, driving studies show driving while on cannabis is far less dangerous than driving on alcohol, including one finding virtually no driving impairment from cannabis. Other studies have found that speed is typically reduced while driving on cannabis, and people deliberately compensate for any impairment, although multitasking was somewhat affected.
In no way does this mean anyone can just toke up and get behind the wheel. Cannabis is psychoactive, and people unaccustomed to cannabis – especially teenagers – should certainly refrain from driving.
The Oregon Commission’s report also supports the premise that cannabis users are more responsible drivers than alcohol use.
“The rate of drivers tested by Drug Recognition Experts who are positive for THC intoxication rose between 2013 and 2014, but did not increase following legalization. Fatal accidents data is highly variable year-to-year, making trend analysis difficult. But in Oregon in 2015 there were only three more traffic fatalities involving a driver testing positive for THC compared to 2004. Moreover, the rate of THC-related fatal accidents is also considerably lower than such accidents involving alcohol intoxication. Finally, while overall traffic fatalities and alcohol-related fatalities spiked in 2015, THC-related fatalities did not.”
As a spokesman for AAA noted when their study was published, the increased risk from driving on cannabis is about the same as driving with a “noisy child in the back of the car,” and only half as dangerous as talking on a hands-free cellphone (legal in all states).While thankfully avoiding an arbitrary blood-THC limit recommendation, the Oregon Commission still felt compelled to offer advice on cannabis and driving. It recommended increasing the use of “Drug Recognition Experts” who administer lengthy sobriety tests specific to cannabis, as well as implementing a voluntary oral swab test to collect data.