Despite the legalization of marijuana in Canada and several U.S. states, the rate of positive drug tests among Canadian cross-border truck drivers has remained consistent. This is according to Jonathan Davids, corporate medical director of DriverCheck Inc., Canada’s provider of workplace medical testing and assessments. He says the stability highlights the critical role of testing, education, and supervisor training in maintaining road safety.

“In regulated trucking, where drivers cross into the U.S. and are subject to Department of Transportation (DOT) regulations, the positivity rates hover around 1%,” said Davids. However, the rates for non-regulated trucking involving domestic routes are about 7%. This is based on ‘hundreds of thousands’ of annual tests for regulated trucking companies and ‘tens of thousands’ of tests per year for non-regulated companies.

Between 2014 and 2018, the rate of positive tests in DOT-regulated trucking was 0.77%. Since recreational marijuana was legalized in October 2018 until the end of 2023, Driver Check recorded an increase of just 1.29%, reaching 0.78%.

According to Davids, regulated trucking has the lowest marijuana testing positivity rates among the various sectors DriverCheck serves, including aviation, construction, health care, manufacturing, mining, public transit, railways, and others.

“This indicates that strict regulations and enforcement in trucking are effective in reducing drug and alcohol use,” he said. “Regulations work. When you have regulated requirements for testing, you have more compliance. People are going to adhere to those regulations, and the numbers clearly show that.”

However, post-legalization, the number of non-DOT positive tests in Canada increased from 5.31% to 7.68% — a 44.6% spike.

While drug testing yields higher positivity rates than alcohol testing, the latter still remains relatively low. The positivity rate is about 0.3% for regulated trucking and 0.4% for non-regulated trucking. Alcohol testing statistics are relatively the same across different sectors, but Davids notes that drug testing shows higher positivity rates.

Provinces across Canada are seeing similar trends.

Quebec sees higher marijuana impairment compared to alcohol

According to the Société de l’assurance automobile du Québec (SAAQ), which licenses drivers and equipment in Quebec, overall, the province has seen low numbers of alcohol and drug-impaired driving offences among heavy vehicle drivers in the province in the period from Jan. 1, 2018, to June 30, 2024.

While the data SAAQ shared with TruckNews.com focuses on arrests rather than convictions, it indicates an overall stable and low incidence of such violations, including drivers of heavy vehicles from Quebec and other Canadian or American jurisdictions.

Overall, in five-and-a-half years, there were 44 arrests related to drug impairment among heavy vehicle drivers in Quebec and 19 alcohol impairment arrests.

The highest number of arrests for drug impairment in the province was seen in 2021, when 11 arrests were made. Since then, the numbers have decreased in half in 2022 and 2023 but rose up to seven arrests in the first half of 2024.

“There are now more options for officers to test for cannabis, and as a result, this has led to an increase in the detection of drug-impaired drivers.”

Mathew Austin, Saskatchewan Highway Patrol

Meanwhile, there has been an increase in drug-impaired driving cases in Saskatchewan. But this rise is not necessarily attributed to more drivers using drugs but rather the improved ability to test for such impairments.

“The ability to test for cannabis has increased drastically since its legalization and the evolution of detection technologies. This is, again, why recent statistics showing an increase in detection and subsequent charges doesn’t necessarily reflect an increase in drug-impaired driving overall, but an increase in the ability to test for it,” said Mathew Austin of Saskatchewan Highway Patrol.

And while marijuana is the most common substance detected, he said in some cases, drivers were found to be impaired by stimulants like cocaine or methamphetamines, too.

The authorities require reasonable suspicion to test drivers on the road for drug impairment. Options include blood and urine testing for compounds like cannabis and others, but it would depend on the jurisdiction of police in the area.

Drug tests are not tests of impairment

The increased focus on adjusting drug testing highlights the importance of understanding the various methods used to detect impairment and the challenges in interpreting the results.

DriverCheck’s Davids points out that a positive test does not necessarily indicate impairment at the time of testing, leading to potential misconceptions about the results.

“Drug tests are not tests of impairment,” he said. “Just because you have a positive drug test, it doesn’t mean you’re actually impaired at that moment. With the exception of alcohol, we can’t determine impairment from the presence of a drug alone.”

This distinction is particularly relevant for THC – the psychoactive component in marijuana – which can remain in the system long after use and lead to positive test results even when the individual is no longer impaired.

According to a recent study by the American Transportation Research Institute, this issue has worsened the driver shortage in the U.S., since the Federal Motor Carrier Safety Administration (FMCSA)’s data indicates that marijuana accounted for more than half of all positive drug tests reported among CDL holders, this has resulted in a substantial number of drivers being suspended.

Drivers who test positive are required to undergo the FMCSA-enforced return-to-duty (RTD) process, which includes evaluation by a substance abuse professional, completion of a prescribed treatment program, and passing a return-to-duty test.

ATRI reports that only 28% of drivers who test positive complete the RTD process, suggesting that many drivers either leave the industry or are unable to meet the stringent requirements for returning to work.

The majority (65%) of carriers and drivers surveyed have indicated they would prefer an industry-wide shift toward a test that indicates recent marijuana use (for example, the day before) instead of the current test that can identify earlier marijuana use.

“When supervisors suspect a driver is impaired, there is a very high likelihood that the driver will test positive.”

Jonathan Davids

There are different testing methods, and currently, in Canada, urine and oral fluid tests play roles in identifying recent versus past drug use. Davids explained that urine tests, for instance, detect substances over a longer period.

Meanwhile, oral fluid tests – which have been gaining increased popularity – are more effective in identifying recent use, particularly for THC, within the last 12 to 24 hours. Meanwhile, hair testing is not widespread since it detects cannabis use within one to three months, and blood tests are considered too invasive.

Driver Check, for example, uses oral fluid and urine tests to determine drug use.

Of all those tests conducted – for pre-employment, post-accident purposes and upon managers’ reasonable suspicion – Davids says the reasonable cause testing, where a supervisor suspects a driver may be impaired, has the highest rates of positive results, going up to around 40%. However, the post-accident testing positivity rates are around 10%.

“Managers must be trained to recognize impairment in employees to prevent accidents,” he said. “The message there is that supervision is important. You have to see and know how your individual workers are functioning. And if you suspect that there’s something going on, if you’re trained to recognize that, then it’s a very high [chance] that you’re right.”

Davids further warns that it’s essential to know that even CBD products – cannabidiol oil, derived from cannabis – which many often mistake as harmless, can lead to positive marijuana tests and even decreased function.

“It doesn’t give you the high, but it does have some sedating and drowsy effects that go along with it, so there are some risks. It hasn’t been quantifiable how risky that is, but there’s some degree of risk with feeling sleepy or drowsy,” he explains. “Most of the products sold in Canada – even if sold as CBD only – have a little bit of THC in it. So, people who are using what’s labeled as only CBD may also be getting some degree of THC. So, if they do a urine test, it’ll come up positive.”

Details like this matter, which is why fleet managers, drivers, and staff have to be educated and have specific policies in place. Davids says some companies even conduct pre-employment drug testing, which is good for safety but sometimes results in a recruitment challenge

“If a trucking company requires pre-employment drug testing, it might deter potential drivers who prefer to work for companies that don’t test,” Davids said.

Canadian drivers traveling to the U.S. are subjected to the same rules and regulations, including RTD processes, mandated by the FMCSA. This is why many Canadian fleets crossing the border choose to adapt the same policies as in the U.S., even for domestic drivers.

Ontario-based Musket Transport, for example, told TruckNews.com that marijuana legalization has not posed a compliance challenge for the carrier.

“Our drivers going to the U.S. must still abstain due to the random testing pool. It may be legal here, but if they test positive on a random, they must still go through the program in order to run in the U.S. Our supervisor training stems from that program as well,” said Daryn Rabb, the company’s health and safety manager.

Is the grass greener on the other side?

The FMCSA’s Drug and Alcohol Clearinghouse reports marijuana remains the most commonly detected substance in positive drug tests among truck drivers. However, there has been a recent downward trend in marijuana positives, FMCSA said in an email to TruckNews.com.

The number of marijuana-positive tests reported in 2023 was lower than the year before, and early data from 2024 suggests that this decline may continue if current trends hold through the second half of the year. Of all the violations reported by July 1, Canadian licence holders account for 4,572 violations, American 25,267, and Mexican – for 2902.

The overall downward trends in marijuana positives might reflect the industry’s adaptation to new legal landscapes, with improved testing, education, and enforcement playing critical roles on both sides of the border.

However, the situation remains fluid, especially since the U.S. may soon reclassify marijuana from a Schedule I to Schedule III drug category, which is considered less dangerous and without potential for abuse. The American Trucking Association has recently expressed concerns regarding what the change would mean for FMCSA regulations since workplaces can only test for Schedule I drugs.