Over the past year, a record number of truckers lost their licenses for testing positive for cannabis and they aren’t taking the necessary steps to get them back, signaling another challenge for a short-staffed industry.

According to the latest estimates from the American Trucking Association, the industry is short some 78,000 truckers. That is down from more than 81,000 in 2021, but only slightly.

According to the fall 2022 report, the shortage looks set to surpass 160,000 by 2031, and the industry will have to recruit some 1.2 million new drivers between now and then.

These 1.2 million new employees will be needed to fill new jobs and to replace retiring drivers, those who pursue different jobs, and those who are disqualified due to failing a drug test.

The number of drivers disqualified for failing a drug test has become of particular concern in light of the latest data from the Department of Transportation’s Federal Motor Carrier Safety Administration.

According to the agency, the number of truckers who lost their commercial driver’s licenses due to failed drug tests rose dramatically last year, to more than 60,000 from about 50,000 in 2021.

Although there has been an uptick in the number of drivers who have lost licenses due to testing positive for cocaine, methamphetamine, and amphetamines — three of the four most common drugs leading to disqualification — an increase in the number of positive tests for cannabis is driving this trend.

According to the Department of Transportation data, the number of drivers who lost licenses for testing positive for cannabis rose to more than 40,000 in 2022 from just over 30,000 in 2021.

As of January, there were about 166,000 drivers who had failed at least one drug test. Of these, only 46,000 have completed the return-to-work process, while 91,000 have not.

“When you take into account legalization efforts across the country, coupled with misinformation about when marijuana use is legal or not, I’m not at all surprised,” the vice president of safety policy at the American Trucking Association, Dan Horvath, told Transport Topics.

The problem with drivers failing cannabis tests is two-fold: On one hand, an increasing number of states are legalizing recreational cannabis, and on the other, drivers are tested for cannabis metabolite.

This means that drivers will test positive for cannabis up to two months after using it. Thus many drivers could be failing the test even though they haven’t used the drug while on the job.

The distinction makes no difference to the Department of Transportation. Any cannabis use is disqualifying for truckers, but the tests for marijuana are substantially different than the ones for other types of drugs.

According to the Federal Motor Carrier Safety Administration, most drugs that are tested for only show up in urine for a few days at most. The only other drug tested for that will show up for weeks after usage is cocaine.

This, combined with the fact that urine samples are often tampered with, has led some researchers at the transportation department to advocate for a transition to a saliva test.

A saliva test would not only allow samples to be collected under direct official supervision, but would be more effective at testing whether drivers were using marijuana while on the job.

Saliva tests have a narrower window for detecting cannabis, around 24 hours, compared to the multi-week or even multi-month window that urine tests analyze.

The Department of Transportation has been considering switching to saliva tests since 2004, but there is no sign that this change will happen imminently.

There are, however, other factors to consider, such as the upward trend in accidents involving large trucks. Between 2010 and 2020, the number of large trucks involved in fatal crashes rose by about one-third. 

While this period did correspond to a time of widespread cannabis legalization, it doesn’t appear to be the cause in the uptick in crashes. Some research has shown that cannabis legalization in certain states may even be associated with a decrease in accidents involving trucks.

According to the American Transportation Research Institute, however, the lack of state-level data on cannabis-impaired driving generally “prevents evaluation of the effect of policy changes on driver behavior.”