Accuracy a concern around roadside saliva-screening device

By Peter Small, Contributor

Roadside saliva-based drug-screening devices being considered for use in Canada may sweep up thousands of innocent drivers in their net if the technology isn’t right, says Toronto criminal lawyer Roots Gadhia.

If you’re utilizing equipment that’s supposed to test whether or not an individual should be pulled off the road, detained and investigated, there shouldn’t be concerns about the accuracy of this testing device, she tells

Under recently introduced legislation, police would be able to demand a saliva sample from a driver if they reasonably suspected the person had drugs in their body, according to the Canadian Press. Should the saliva test lead police to believe an offence has been committed, they could order a blood sample or an examination by an evaluating officer, the article says.

The federal government, which plans to legalize marijuana by July 2018, has declared Canada-wide testing of the drug-screening devices a success despite lingering issues over how accurate the results are in cold weather conditions, the CBC reports.

Testing conducted by several police forces shows that the devices were more likely to produce a drug-positive result in cold conditions such as exist in Canada, says the broadcaster.

Gadhia says it’s vital to keep the roads free of drug-impaired drivers, but we need to get the technology right.

“You should have something that you can rely on, that you can trust, before you put it out on the streets,” she says.

Gadhia, principal of R. Roots Gadhia Criminal Defence Law, says the stakes have risen in the wake of the Ontario government’s announcement of stiffer penalties for drivers caught with drugs in their system.

Under the proposed rules, young or novice drivers (with a G1, G2, M1 or M2 licence) would face licence suspensions from three to 30 days and fines from $250 to $450 if they have drugs or alcohol in their system, the Canadian Press reports. Currently, young and novice drivers face a 24-hour licence suspension and no monetary penalty, it says.

Commercial drivers would face a three-day licence suspension and fines from $250 to $450 if they have drugs or alcohol in their system. Currently, there are no targeted suspensions or monetary fines for commercial drivers under Ontario’s impaired driving laws, says the article.

Gadhia notes that saliva-screening devices can detect the presence of THC — the active ingredient in cannabis — plus cocaine, amphetamines, opioids and benzodiazepines, but they can’t tell you when the drugs were consumed.

“If you smoke a joint on Saturday and then on Monday afternoon or Tuesday you’re pulled over, you’re going to have THC in your saliva,” Gadhia says. “The difficulty then becomes how do you prove impairment at the time of driving?”

There is no scientific consensus on how to overcome this problem, she says. “This is literally a leap of faith.”

Gadhia says police have wide discretion to pull people over if they suspect impairment. Seeing a driver swerve slightly while tuning the radio could trigger a police stop, she says.

There is a risk that some visible minorities, particularly blacks, will be disproportionately targeted and given the saliva tests, she adds.

“Failing the saliva test will allow officers not just to ask for a blood sample but to search their vehicle, search their person and put them under arrest,” Gadhia says. That would lead to a trip to the police station, and likely examination by a drug recognition expert, she adds.

“There isn’t enough control over the process and many people are going to get caught up in this large net,” she says.

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