As medical marijuana spreads its leafy green arms across North America, municipalities are grappling with how to prevent clearly non-intoxicated patients from running afoul of the law when they get behind the wheel.
With studies showing tiny amounts of THC can remain in the human body for up to 30 days after cannabis use, untold numbers of drivers who are prescribed the drug for medical reasons are at risk of police action even if they have not used their medicine in weeks.
In Pennsylvania, where police take a zero-tolerance approach to cannabis use and driving, a lawmaker has introduced legislation to clear the air on what is allowed.
Chris Rabb, a Democrat from Philadelphia, said he uses the drug himself every night before going to sleep, according to the Philadelphia Inquirer, but this should not mean he can’t drive the next day.
“What’s important to note is that that ‘influence’ does not impair me,” Rabb said. “I’m not driving recklessly. But that doesn’t matter to most police officers. Law enforcement has a dim view of any legalized cannabis use,” he said.
Because the federal government has resisted removing marijuana from that list, states have been forced to find solutions on their own. / Photo: Getty Images
The legislation Rabb introduced on Tuesday would modify the state’s DUI statute that currently forbids the presence of any amount of a Schedule 1 controlled substance in a motorist’s blood. Because the federal government has resisted removing marijuana from that list — which also includes harder drugs like heroin — states have been forced to find solutions on their own.
Rabb’s bill would modify Pennsylvania’s statute to include an exemption for “marijuana used lawfully in accordance with the act… known as the Medical Marijuana Act.”
The proposal, which has plenty of support from Democrats, has not been able to find a Republican co-sponsor as of yet.
Like alcohol, cannabis impairs skills commonly associated with safe driving, such as quick reflexes and undivided attention. At the moment, however, research into how much cannabis impairs motorists and methods for accurately testing how much marijuana they have consumed are very limited.
A study conducted in Canada using toxicology results from trauma centres in B.C. has given a little more insight into what impact blood marijuana level has on crashes. Of the 3,005 toxicology reports the study received, alcohol was involved in 14.4 percent of crashes. THC was involved in 8.3 percent, other drugs in 8.9 percent and sedating medications in 19.8 percent.
The study found there was no increased crash risk in drivers with under two nanograms or with two to five nanograms of THC per millilitre of blood, and minimal increase in drivers with over five nanograms of THC per millilitre.
There was “significantly increased risk of crash responsibility” in drivers with a blood alcohol concentration of over 0.08%. / Photo: iStock / Getty Images Plus
Conversely, there was “significantly increased risk of crash responsibility” in drivers with a blood alcohol concentration of over 0.08%.
The study speculates that drivers under the influence of cannabis are aware they are impaired and so drive more carefully.
While driving impaired is a clear risk to the driver’s life and others, the way police services are evaluating impairment as a result of cannabis consumption is considerably more complex. Roadside testing devices depend on saliva samples to screen for the presence of THC and other drugs — they do not test for impairment.
To further complicate matters, several studies have indicated that results provided by testing devices used by police are inaccurate and may be triggered after ingesting substances as benign as poppyseed cake, per two B.C. lawyers.
A Nova Scotia medical cannabis consumer with multiple sclerosis said she learned this lesson the hard way.
Michelle Gray, who was pulled over for a routine traffic check, was initially unconcerned as she had not consumed any cannabis for at least six hours before getting behind the wheel. However, a roadside screening device gave a positive result for THC.
Gray was arrested and taken to a Halifax police station where she easily passed a more intensive sobriety test. No charges were laid, but she missed several days of work and had to pay $300 to retrieve her car. She is now challenging the law in court.
Until the matter reaches resolution in a court of law, there would seem to be no easy answers. Developing a test that can reliably detect recent cannabis use would be a great start, but researchers have been thwarted by the drug, in no small part due to the multiple methods in which it can be ingested and processed by the body.
“We’re applying the alcohol rules to a substance that doesn’t play by them,” Nick Morrow, a retired Los Angeles Sheriff’s Department narcotics investigator, told CNN.
In the meantime, the best advice for motorists who aren’t able to abstain from cannabis may be to keep their medical marijuana cards on their person and their eyes on the road at all times.
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