Behind the Wheel at Work

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Behind the Wheel at Work is a quarterly eNewsletter bringing you the latest news from the NIOSH Center for Motor Vehicle Safety.

Volume 5 Number 4 January 2021

Marijuana and Driving: Keep Your Fleet’s Drivers Safe

What’s the difference between cannabis and marijuana? What are the effects of marijuana use on driving? How can employers reduce the risk of impairment from marijuana use among drivers? Let’s explore answers to these and other questions.

Update on the Coronavirus Disease 2019 (COVID-19) Response

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Marijuana Use and Driving: The Science

Marijuana leaf drawing

The Bottom Line: Despite some unanswered questions about marijuana’s role in crash risk, workers impaired by marijuana do not have the skills needed to drive safely.8-10 Because marijuana use is on the rise for adults in the United States, this substance needs to be addressed as a part of all motor vehicle safety programs.

Safety Tip
warning sign yellow, exclamation mark icon

You may receive an accommodation request from a worker for medical marijuana use in a state which requires accommodation. Consider using methods applied to other protected employees (e.g., employees with disabilities) to ensure safety, such as moving the employee out of safety-sensitive position, using alternative scheduling, or changing the employee’s duties.

How Employers Can Address Motor Vehicle Safety Risks Related to Marijuana Use

NIOSH Marijuana logo

Acknowledgement: Natalie Hartenbaum, MD, MPH, FACOEM (OccuMedix)

Managing motor vehicle crash risks associated with marijuana impairment is not simple, but it is important. Marijuana impacts a driver’s cognitive abilities. Its use in the U.S. is increasing as more states legalize its recreational use. Other than alcohol, marijuana is the most frequently reported drug found in post-crash testing.

Here are a few tips for reducing your workers’ risk of impairment from marijuana while driving on the job:

  • Develop a comprehensive marijuana policy that accounts for current laws in each state where your company operates.
  • A zero-tolerance policy for marijuana may not be possible, depending on your state’s laws. However, the best marijuana policies will:
    • Prohibit workers using marijuana in any form while at work.
    • Prohibit workers from being impaired from marijuana at work.
  • Partner with an attorney to review your policy and provide feedback. Make sure the attorney understands state marijuana laws and is up-to-date on marijuana-related case law.
    • Determine if there are employee protections or accommodations for using marijuana during off-duty time, and if those protections include medical and non-medical use.
    • Determine if drug tests are permitted and under what conditions you can test. If tests are permitted, determine what actions can employers take in the event of a positive test.
    • Find out if there are state designated “safety sensitive” positions or if you, as an employer, can designate your own safety sensitive jobs and job tasks.
    • Find out if there is an established threshold for determining marijuana impairment.
    • Check regularly to see if there are recent changes to any state marijuana laws. Four statesexternal icon legalized non-medical marijuana for the first time on Election Day 2020 (Arizona, New Jersey, South Dakota, and Montana).
  • Outline specifics of drug testing if it is a part of your marijuana policy.
    • Make sure your policy describes the conditions under which testing will occur (e.g., ongoing periodic random testing, anytime impairment is suspected, or only after a crash), the threshold that will constitute impairment, and the consequences of a positive test.
    • Ensure that your testing activities follow the steps outlined in your policy.
    • Seek out and use a medical professional with training in interpreting THC drug tests.
    • Warn drivers that Cannabidiol (CBD) product labeling is not regulated. Labeling is frequently inaccurateexternal icon. Consumption of CBD products with significantly higher levels of THC than what is on the producer’s label could result in a positive drug test.
  • Provide access to support for employees with drug problems, either through in-house programs or referrals to local resources.
  • Educate drivers on:
    • The effects of marijuana and other drugs on safe driving and cognitive abilities.
    • The details of your company’s marijuana policy, including special considerations for the state or states where they work.
    • Similar impairments that can result from fatigue, medications, and certain medical conditions.
  • Train managers and supervisors on:
    • The details of your marijuana policy.
    • The specific responsibilities of managers/supervisors outlined in the policy.
    • How to recognize and document signs of impairment.
  • Once you implement your policy, conduct regular review and monitoring of the relevant state marijuana laws and any improved methods for determining impairment. Update your policies as needed. As with other safety policies, they will continue to evolve and improve.

Bottom Line: Motor vehicle crash risks posed by marijuana impairment of employees can be managed effectively with comprehensive state-specific policies, worker and supervisor training, employer-provided support for workers struggling with drugs, and a partnership with an attorney who has expertise in state marijuana laws and related case law.


National Institute on Drug Abuse: Drugged Driving DrugFactsexternal icon

Webinar Recording Available
Marijuana and Driving 2020 Webinar graphic

Are you facing increasing questions about impaired driving as a result of marijuana laws? The National Institute for Occupational Safety and Health (NIOSH) Center for Motor Vehicle Safety hosted a webinar to answer these questions on September 16, 2020. Marijuana and Driving: How to Keep Your Fleet Safe is now available to view via recording.

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Page last reviewed: January 22, 2021