Recognizing this, the DOT has continued to classify marijuana as a Schedule I substance. The Department of Transportation enforces a strict zero-tolerance policy for marijuana use among commercial truck drivers.

In some ways, marijuana intoxication is worse than alcohol. Alcohol’s effect typically wears off within 8 hours, marijuana intoxication can lead to impairment for up to 36 hours after a single use.

The DOT’s drug testing program includes pre-employment, random, post-accident, and reasonable suspicion tests. DOT drug tests require laboratory testing for cocaine, opiates and codeine derivatives, amphetamines and methamphetamines, PCP, and marijuana.

Testing for Marijuana Usage is Complicated

No truck driver should be driving after using alcohol, recreational marijuana, or other prohibited drugs. The difference, however, is how long an active ingredient can stay in the bloodstream. A blood test can measure alcohol in a person’s body for up to 6 hours after their last drink, while breathalyzer tests work for between 12 and 24 hours. Urine tests are also effective for around 12-24 hours after use. Typically, THC, the psychoactive component of marijuana, is detectable for up to 90 days in hair, anywhere between 1 day to a month or longer in urine (depending on how often the individual uses it), up to 24 hours in saliva, and up to 12 hours in blood.

CBD (cannabidiol) products complicate drug testing. These cannabis-based products are non-intoxicating. They are marketed as an alternative for pain relief, anxiety, and sleep disorders. Many truck drivers use CBD products to manage the physical demands of the job. However, DOT-mandated drug tests for marijuana can detect trace amounts of the active ingredient that makes marijuana an intoxicant. This false positive can occur even in some CBD products labeled as “THC-free.” In some cases, these minute amounts of THC can build up over time and become detectable. Drivers can end up testing positive for THC and face disqualification.

If a driver tests positive for THC, they are immediately removed from driving duties and must complete a return-to-duty process. This process can be costly and time-consuming. Often, it simply results in permanent job loss or long-term unemployment for the driver.

Since 2020, over 100,000 truck drivers have tested positive for past exposure to marijuana. Most of those positive tests came via pre-employment screening. Those who fail random tests are required to enter a ‘return to work’ program, which includes passing a drug test to have their license reinstated. However, only about one-quarter of those who failed the test have gotten their license renewed.

It is erroneously claimed by a trucking industry advocacy group that there is a significant truck driver shortage. But if you believe in free markets, you understand that raising wages will lead to an influx of new drivers. What we have is a shortage of drivers willing to work at the present wage rates for a fatiguing job that has long hours and contributes to health issues. Nevertheless, it is true that negative drug tests dissuade new workers from entering the field, contribute to drivers leaving the field, and thus increase the costs of hiring new drivers and retaining them.

What is the Trump Administration’s Position?

Trump’s selections to lead relevant agencies such as the Department of Justice and the Drug Enforcement Agency will have an impact on the future of marijuana rescheduling. Marijuana was not a topic of discussion at the confirmation hearings for Attorney General Pam Bondi. On February 11, 2025, Trump announced the nomination of Terrance Cole for DEA administrator. Cole has expressed opposition to marijuana reform.

The topic also received scant attention at newly confirmed US Department of Health and Human Services Secretary Robert F. Kennedy’s nomination hearings. Kennedy stated that he would defer to the DEA on marijuana rescheduling. Although RFK has previously called for cannabis decriminalization, he has recently been silent on rescheduling efforts and instead has said that he will defer to the DOJ and DEA in the allocation of their resources and development of their priorities.

Is Better Testing Possible?

Hair follicle tests can provide a more accurate picture of recent use without penalizing drivers for past consumption of a legal drug. Oral fluid tests have been approved by the DOT but are currently not available because the Health and Human Services has to first approve at least two labs to conduct testing. Once those labs are approved, truck firms will have an option for oral testing.

Urine tests have also been suggested. However, oral fluid tests are less likely to involve cheating than urine tests. Urine testing is susceptible to drug users passing off clean urine from a third party as their own.