ATRI Assesses Impact of Marijuana Use on Trucking

Many Drivers Leave Their Jobs After Failing Drug Test
Marijuana drug test image
(RapidEye/Getty Images)

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More than 100,000 truck drivers have been removed from the industry in the past three years due to positive marijuana tests, and most have not returned, according to a new study by the American Transportation Research Institute.

ATRI released the report, “Impacts of Marijuana Legalization on the Trucking Industry,” on June 5 in response to concerns about the increasing use of marijuana by truck drivers largely believed to be due to the recreational legalization of pot in 23 states. Drivers also can be placed in a prohibited status even for testing positive while using the drug for medicinal purposes.

“In all likelihood, more states will move in this direction since a majority of Americans (59%) support legalization,” the report said.

The ATRI report seeks to shed light on the continuing mystery of why so many medium- and large-truck drivers are leaving their jobs after failing a marijuana test — most likely accepting other jobs with lower pay rather than returning to the current nationwide driver pool that already is critically short.

“Based on Drug and Alcohol Clearinghouse data, marijuana use clearly has an impact on the availability of truck drivers,” the report concluded. “Data confirms that most have not completed the return-to-work process and instead opt to remain outside of the interstate trucking industry.”

“Furthermore, truck drivers who do successfully return to duty may still find it difficult to find truck driving employment, based on carrier survey data indicating that a segment of carriers will not hire truck drivers who have tested positive.”

The mean annual wage for a heavy-duty truck driver is currently $50,340, but only $42,630 for a light-duty truck driver, according to the study.

The ATRI analysis also documents the strategies and implications of the two pathways the federal government can take in response to advancing legalization efforts.

About ATRI

The American Transportation Research Institute has been engaged in critical transportation studies and operational tests since 1954.  ATRI is a 501(c)(3) not-for-profit research organization headquartered in Washington, D.C., with offices in Atlanta, Minneapolis, and Sacramento. ATRI’s primary mission is to conduct transportation research, with an emphasis on the trucking industry’s essential role in a safe, efficient and viable transportation system.

The first pathway, maintaining the current prohibition policy where marijuana remains a Schedule I drug, would continue the trend of removing thousands of drivers annually from the industry through positive tests for past marijuana use, ATRI said.

The second pathway, a scenario in which the federal government eases restrictions and possibly removes marijuana from the Schedule I designation, has significant challenges as well. Prior to any federal legalization action, the report identifies several protections that must be in place for employers in safety-sensitive industries. These include the development of a nationally recognized marijuana impairment test and impairment standards, as well as provisions that protect a carrier’s ability to screen employees for drug use.

The ATRI study noted that the Centers for Disease Control and Prevention, said the THC (tetrahydrocannabinol) contained in marijuana “is a psychoactive (mind-altering) compound that affects areas of the brain that control the body’s movements, balance, coordination, memory and judgment.

Marijuana legalization map

Source: American Transportation Research Institute; graphic: Transport Topics

“The impacts of marijuana also include impaired coordination, distorted perception, memory loss and problem-solving difficulties, as well as decision-making capabilities and reaction times, which can be slowed by marijuana,” the ATRI report said.

The report maintained that should the federal government maintain current marijuana laws, the trucking industry will continue to have thousands of drivers annually placed in prohibited status and will lose many others to occupations that do not test for marijuana use.

“Ultimately, this puts pressure on the availability of CDL drivers,” the report concluded.


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ATRI’s study said that employers of CDL drivers likely compete for drivers with shorthaul parcel delivery companies that have emerged with the shift to e-commerce.

“While these positions typically pay less, there are nonmonetary benefits such as increased home time,” the report said. “Additionally, non-CDL positions are not required to submit to pre-employment screening (though some employers continue to test non-CDL drivers for insurance and liability reasons). While there is little evidence that longhaul truck drivers are migrating to non-CDL positions explicitly because of marijuana testing policies and regulations, legalizing marijuana may be a motivator for truck drivers to migrate to positions that do not require drug testing.”

The ATRI report also includes industry surveys that provide insight into motor carrier and truck driver perspectives on the consequences of marijuana legalization and current drug screening regulations.

“The data collected show that drivers and carriers are equally frustrated with current drug-testing limitations, in particular the lack of a test for marijuana impairment,” the report said.

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Testing impaired individuals through a quantitative measurement —– which has been key to combating drunken driving — remains elusive in the case of marijuana, the study points out.

“There is not even a definition or quantitative threshold for marijuana impairment,” the study said. “Testing CDL drivers for drug use is a logical approach to support highway safety, and marijuana-impaired drivers should never operate heavy-duty trucks.

“That said, marijuana remains detectable for weeks, while alcohol and most recreational drugs are only detectable for a matter of days or even hours when using U.S. Department of Transportation-approved testing methods. This fact has led to the removal of many thousands of drivers from the industry based solely on past marijuana use.”