More Regulation Needed for Marijuana Usage Among Truck Drivers

As medicinal and recreational marijuana become legalized in more states, concerns about driving while impaired by the drug have grown. In truck drivers specifically, it often leads to crashes when used in tandem with other drugs or other poor driving conditions, ultimately resulting in deadly outcomes.

In April of 2025, a truck driver was accused of killing three construction workers in York County, Pennsylvania while impaired by marijuana and lack of sleep. Another instance from April 2023 included a seven-vehicle crash in Garvin County, Oklahoma that resulted in two deaths. The driver admitted to smoking marijuana before his shift and was using his phone at the time of the collision.

Of the states that Craig, Kelley & Faultless attorneys are licensed in, THC is recreationally legal in Michigan, Illinois and Ohio, as well as medicinally legal in Kentucky. And while it may be completely legal in other states, there are issues in states like Indiana where it is not.

One of those issues comes in the form of Delta 8/9, which is derived from the hemp plant. The 2018 Farm Bill allows the legal status of the substance, which was passed so that farmers could grow industrial hemp and sell CBD products across state lines. But hemp is still derived from the Cannabis genus, meaning it contains small amounts of THC, allowing users to still achieve a high and test positive for marijuana in a drug test.

Between legal marijuana and the use of hemp-derived imitations of the drug, it is now easier than ever for people to obtain these mind-altering substances. Furthermore, legalization is happening so quickly that law enforcement and studies of impaired driving struggle to keep up.

Impact of Marijuana Legalization on Road Safety

The Center for Diseases Control (CDC) states that the THC in marijuana “is a psychoactive (mind-altering) compound that affects the areas of the brain that control the body’s movements, balance, coordination, memory and judgement.”

Other impacts of the drug include impaired coordination, memory loss, distorted perception, and problem-solving difficulties. The American Transportation Research Institute’s main concern for drivers using the drug is that decision-making abilities and reaction times can be slowed.

While marijuana is legal in some states, it is still illegal to drive while impaired.

Currently, there is not a sufficient amount of research to show how significantly marijuana usage impacts roadway safety. However, there is evidence that it negatively impacts highway safety statistics, specifically.

One study suggested that “in the year following the implementation of recreational cannabis sales, traffic fatalities temporarily increased by an average of one additional traffic fatality per million residents,” according to the American Transportation Research Institute. This study from 2019 examined Oregon, Washington, and Colorado after legalization, as well as nine other neighboring control states where the drug was still illegal.

Another study from 2022 concluded that the “legalization of the recreational use of marijuana and the subsequent onset of retail sales in five states was on average associated with a 5.8% increase in injury crash rates and a 4.1% increase in fatal crash rates.”

Additionally, the research acknowledges that impairment from cannabis causes drivers to slow their speeds and increase following distances. However, this compensation by impaired drivers may not be sufficient to avoid a crash, only the severity of it, which explains the higher increase in injury crashes than fatal ones.

Overall, drugged driving is an under-recognized highway safety problem, with the exact impact it has on highway safety remaining unknown. The Michigan government believes increased levels of driver impairment may have to do with increased potency of THC over the years. In the 1960s-1970s, most cannabis products contained 3% THC. As of 2016, that number can be up to 30%. Infused and edible forms of the drug can also raise THC to dangerous levels.

Drivers may also be unaware that impairment from marijuana persists for four to eight hours, well beyond the time it takes for the initial effects of the drug to dissipate. Residual effects from smoking cannabis can last up to 24 hours.

General impairment mostly affects reaction time while driving in the forms of difficulty with lane position, needing larger distances to pass other vehicles safely, struggling with secondary and divided attention tasks, and visual field/visual tracking issues.

Marijuana Usage and Its Effect on the Trucking Industry

The Federal Motor Carrier Safety Administration (FMCSA) probits commercial driver’s license (CDL) truck drivers from testing positive for marijuana. This is true even for drivers of semis or other heavy trucks who live in states where it may be legal to smoke and consume marijuana.

Any positive test for past drug use can lead to employment termination. For truckers specifically, anyone holding a CDL must pass a drug test during pre-employment, at random intervals, post-accident, and when there is reasonable suspicion of drug use.

Of all the violations reported by the Federal Motor Carrier Safety Administration (FMCSA) Clearinghouse, positive drug tests account for 81%. This includes 34,936 positive tests in 2024 for marijuana metabolite (Delta 9-THCA) usage in 2024, and a total of 184,839 positive tests from 2020 through April 2025. This accounts for 59% of substances identified in positive tests.

There is a total of 291,664 CMV drivers that have at least one drug/alcohol violation, with 184,337 that are currently in prohibited status. The FMCSA forces drivers with a “prohibited” Clearinghouse status to lose their CDL and complete a return-to-duty process to earn it back. This applies to all commercial motor vehicles (CMVs), not just semi-trucks. Additionally, all employers must conduct Clearinghouse queries when new drivers are hired, as well as conducting an annual query of all the license holders under their employment. Any refusal of drug/alcohol testing is treated as a positive test, resulting in “prohibited” status.

Statistics show that of the truck drivers who do test positive, most do not complete the return-to-duty process, choosing instead to no longer work within the trucking industry. Drivers who do return experience hardships finding new employment because some carriers refuse to hire drivers that previously tested positive.

In recent years, driver shortages have fluctuated between 65,000 and 80,000, and the removal of drivers who test positive for drugs contribute to this shortage.

The current testing is effective at keeping drivers who may work while impaired from getting behind the wheel, but it also removes drivers from the job who may participate in recreational use in legal states that would not operate a CMV while impaired. Some carriers are concerned that the increase in positive tests for cannabis in post-crash screenings are linked to widespread legalization, considering that marijuana can remain in a person’s system for up to 30 days after use.

The current controlled substance regulations for CMV drivers state that they cannot report for and be on duty when using any drug or substance identified in Schedule I, or when using any non-Schedule I drug listed in other schedules without receiving medical instruction to do so. However, based on surveys cited by the American Transportation Research Institute, many drivers are not fully aware of the rules surrounding cannabis use.

A survey taken of 3,302 drivers found that 19.1% of the participants were not sure of the rules regarding cannabis use for CDL holders in legal states. 6.6% of respondents believed CDL holders could use marijuana recreationally in a legal state while off-duty. When asked about how legalized marijuana use impacted highway safety, 55.4% stated that there was no impact.

Additionally, 28.6% of participants (the majority) thought it was possible to safely operate a vehicle 10 hours after using cannabis. Others believed driving was safe from a time ranging from immediately after use to up to 10 hours after. Due to lack of research, there is no definitive scientific answer to this question, but the responses show a potential of poor judgement from drivers regarding roadway safety when it comes to drug use.

Overall, there needs to be an industry-wide effort to improve driver education around drug use. One comment from a respondent stated: “As professional drivers, we need to be held to the highest standard, not only for our safety but for everyone else’s safety. No way should it be legal to use if you hold a CDL.”

Improvements Needed to Prevent Marijuana Impaired Driving

Limited funding and constrained access to marijuana for research due to lack of federal legalization makes it difficult to fully understand the effects the drug has. The American Transportation Research Institute states there is a need for more robust data at state and federal levels, and that safety campaigns should be employed to mitigate the number of impaired drivers.

More importantly, law enforcement needs better tools and training to identify drivers impaired by cannabis. Currently, there is no quantitative field sobriety test for marijuana like there is for alcohol.

The laws that do address drugged driving are nuanced, difficult to enforce and therefore prosecute, and vary substantially from state to state. However, while there is no standard approach in the United States to identify drivers under the influence of marijuana, there are two primary approaches law enforcement can use to document impairment.

The first one is behavior-based, meaning the evidence is collected from conducting the field sobriety test used for alcohol impairment. But when using this test for cannabis-users, the results can be flawed.

The second option is biology-based, which involves measuring the concentration of THC in a person’s blood. Some state laws state that anything greater than 0ng/ml of THC in the blood is indicative of impairment, but other states may vary in the levels they allow. There are currently 10 states where a positive metabolite test indicates impaired driving.

However, this method is flawed for a couple reasons. Metabolites can be present for several weeks after use, meaning the driver may not have been driving under the influence. It also takes time for police to bring a suspect in for questioning and then do a blood test. By the time the blood test is taken, the driver may no longer be legally considered impaired depending on state laws.

Overall, more research needs to be done to properly assess whether a driver was under the influence of marijuana at the time of a traffic stop or crash. And as more states legalize the substance, the more likely it is that drivers will have positive tests from using the drug while off-duty.

Unfortunately, our law firm Craig, Kelley & Faultless has represented several people who have been injured by semi-truck drivers who were impaired from marijuana.

“It is extremely frustrating that some truckers ignore the dangers of being impaired from marijuana and endanger everyone on the roadway near their big rig,” Attorney David W. Craig said.

Final Thoughts

Marijuana and alcohol continue to be the drugs most commonly detected in impaired driving crashes that result in serious or fatal injuries. In fact, between 2000 and 2018, deaths in collisions that involved marijuana more than doubled, rising from 9% to 21.5%. Furthermore, evidence shows that crash risks increase by 22% while under the influence of cannabis, controlling for concurrent alcohol use.

Attorney David W. Craig, who is board-certified in truck accident law by the National Board of Trial Advocacy and accredited by the American Bar Association, stated that he often handles cases where semi-truck and other CMV drivers tested positive for marijuana alongside other drugs, typically stimulants or uppers to stay awake for long periods. This combination of uppers and downers, like marijuana, can make this impaired driving even more dangerous than just cannabis on its own.

Ultimately, both the federal government and the trucking industry need to put more effort into identifying drivers who operate trucks while impaired, as well as educating drivers on the rules and regulations they must follow to keep their CDLs and keep others safe on the roads.

Injured by an Impaired Driver? Craig, Kelley & Faultless Can Help

Attorneys at Craig, Kelley & Faultless are prepared and have the experience to help victims and their loved ones involved in commercial vehicle wrecks through every aspect of their case. Both David W. Craig, Scott A. Faultless are board-certified in truck accident law by the NBTA, accredited by the American Bar Association. The firm also has a rapid response team—including investigators, reconstructionists and mechanics—that is sent to the scene of a wreck to collect evidence as soon as the firm is hired.

Their team-centered approach puts client needs at the forefront, and several attorneys will work on your case to achieve the best possible outcome.

Reach out for a free case consultation today at (800) 746-0226 or online.

 

David W. Craig is board-certified in truck accident law by the National Board of Trial Advocacy, accredited by the American Bar Association in Truck Accident Law. He sits on the Board of Regents of the Academy of Truck Accident Attorneys. He is the managing partner and one of the founding partners of Craig, Kelley & Faultless LLC. He is recognized as a Top 10 Trucking Trial Lawyer and Top 100 Trial Lawyer in Indiana by the National Trial Lawyers, as well as a Top 50 Indiana lawyer by Super Lawyers. David is the author of Semitruck Wreck, A Guide for Victims and Their Families and It’s Never Been Easier to Hire the Wrong Attorney, both written to help people navigate what comes next after a tragic wreck. He also hosts the podcast After the Crash, where you can gain valuable information about the dangers involving semis and large trucks that do not follow safety protocol regarding speed, weather conditions, maintenance upkeep, etc.