What cops get wrong about pot-impaired driving
With the legalization of marijuana, pot holes aren’t the biggest concern on the road — pot-impaired drivers are. Police officers are desperately trying to answer the question: is this driver high on cannabis?
With1-in-3 Canadians saying they have ridden in a car with a high driver, police chiefs pleaded for a rapid test for THC akin to the breathalyzer for alcohol. Politicians scrambled to approve a saliva screening test. But police chiefs are worried the test is unreliable and some are even refusing to use it.
Good. It was never the right test in the first place.
Police officers don’t need to detect marijuana use in drivers, they need to detect impairment — regardless of the drug or its legality.
Impaired driving kills an average of four Canadians every day. Impaired drivers have poor judgment, reaction time, co-ordination and motor skills. These are physical characteristics that require a physical test, not a microscopic one.
We can test impairment in driving simulators, and we can also test possible roadside predictors to develop the right test. A well-developed roadside test that focuses on global impairment will be better than any breathalyzer, saliva test, or blood test. Best of all, it will be future proof.
There were THC-impaired drivers on the road prior to legalization, and there will be THC-impaired drivers post legalization. And there are impaired drivers on the road right now who aren’t using alcohol or marijuana. Opiates impair driving — and it doesn’t matter if it’s morphine prescribed by a doctor or heroin bought on the street. The legality of a substance doesn’t change its risk.
Police have no objective roadside test for opiates. Or for MDMA, ketamine, GHB, crystal meth, LSD, magic mushrooms or any future drug someone could take before getting behind the wheel.
Breathalyzers and blood levels aren’t perfect tests for safety, even for alcohol. That’s why in the emergency department, where I work, we don’t rely on blood tests to determine whether someone is intoxicated. We are trained to determine impairment clinically at the bedside.
Can police officers be trained to do clinical assessments like a doctor? Actually, they already are. Police officers use the standardized field sobriety test (SFST), which was developed to correlate with blood alcohol concentration.
The SFST has three parts. Two are fairly simple to assess: walking in a straight line and standing on one leg while doing a mental task. The third part is more complex and involves as assessment of involuntary eye jerks — and police officers do this complicated assessment regularly. With concerns over the roadside saliva test, police officers have begun to use the SFST to test for cannabis impairment.
Admittedly, there are significant flaws with the current SFST.
For alcohol, 1-in-10 times it determines that someone is safe to drive when they are actually above the legal limit. It performs even worse for other drugs, only identifying half of people with high THC use. But it is important to understand that the SFST was developed to correlate specifically with blood alcohol concentration, and not to correlate with impairment generally. And since blood levels don’t perfectly predict impairment, the SFST answered the wrong question in the first place.
Think about the last time you were on a crowded airplane. It’s stuffy and the person sitting next to you has monopolized the shared armrest. You can’t wait to land and get out. The pilot comes on the speaker and an announces that you only have 6,000 metres to go before you land. You don’t care about altitude, even though it’s correlated to thing you really care about: the time before you can get up and stretch your aching legs. Altitude is the right answer to the wrong question.
The legalization of marijuana has highlighted that impaired driving is not just about alcohol. We shouldn’t repeat the same mistake now and make impaired driving just about alcohol and marijuana.
Our police officers shouldn’t be demanding a better saliva test for marijuana, they should be demanding better training at recognizing impaired driving regardless of the substance or its legality.
Our policy-makers need to see the big picture, and put resources into developing the right test to answer the right question: is this driver impaired?