Rules of the road
Updated September 28, 2026
A DOT drug test checks your urine for five classes of drugs: marijuana, cocaine, opioids, amphetamines (including MDMA), and PCP. A DOT alcohol test measures your alcohol level, and 0.04 or higher is a violation.
CDL drivers are tested before they first drive for a carrier, at random, after certain crashes, and when a trained supervisor has a reasonable suspicion. After a violation, you cannot drive again until you finish the return-to-duty process.
This guide covers what the tests look for, when you get tested, and every step back to work after a violation. It comes from a carrier, not a lab selling tests, and each rule links to its source.
What Drugs Does DOT Test For?
A DOT drug test is a lab test of a urine sample. The federal lab rules list exactly what the lab looks for:
| Drug class | What the lab tests for |
|---|---|
| Marijuana | THC metabolite |
| Cocaine | Cocaine metabolite (benzoylecgonine) |
| Opioids | Codeine, morphine, hydrocodone, hydromorphone, oxycodone, oxymorphone, and 6-acetylmorphine (6-AM) |
| Amphetamines | Amphetamine, methamphetamine, MDMA, and MDA |
| PCP | Phencyclidine |
Each drug has a cutoff level. A result below the cutoff is reported as negative. A result at or above it goes to a second, confirming test.
Marijuana and state law. The DOT has said state marijuana laws have no bearing on its testing program. Its rules do not allow marijuana use for any reason by drivers who are tested, whether for medical or recreational use. A doctor’s recommendation will not turn a positive result into a negative one.
A carrier can also run its own company tests for other drugs. Those are separate from DOT testing, and the carrier must say clearly that they are its own policy.
When Drivers Are Tested
These rules cover nearly every CDL driver on public roads, full-time or part-time. There are six kinds of tests:
Pre-employment
Before you drive for a carrier the first time, it generally must have a verified negative drug test. An alcohol test here is up to the carrier.
Random
Unannounced tests all year. For 2026, FMCSA’s minimum is drug tests equal to 50% of driver positions and alcohol tests equal to 10%.
Post-accident
Always after a crash with a death. After an injury treated away from the scene or a tow-away, only if you are cited. Alcohol tests stop after 8 hours, drug tests after 32.
Reasonable suspicion
When a trained supervisor sees specific signs in your appearance, behavior, speech, or smell, and writes them down.
Return-to-duty
After a violation, once you finish the steps below. It is directly observed, and you need a negative result to drive again.
Follow-up
Unannounced tests after you return: at least 6 in your first 12 months back, and possibly more for up to 4 more years.
Refusing a required test is treated the same as failing one in most cases. You are pulled from driving until you finish the return-to-duty process.
DOT Alcohol Testing
DOT alcohol tests find alcohol at 0.02 and above. What happens next depends on the number:
What your alcohol test result means
- Under 0.02No actionThe DOT alcohol rules take no action on a result this low.
- 0.02 to 0.039Off duty 24 hoursNot a violation, but you stop safety-sensitive work until your next scheduled shift, and for at least 24 hours.
- 0.04 and upViolationYou cannot drive until you finish the return-to-duty process.
Before duty: you may not do safety-sensitive work within 4 hours of drinking alcohol.
After a Violation: The Return-to-Duty Process
A violation means a verified positive drug test, an alcohol result of 0.04 or higher, a refusal, or other drug or alcohol use the rules forbid. From there, the path back has set steps:
- You are removed from driving.The carrier must take you off all safety-sensitive work right away.
- You see a substance abuse professional.A DOT-qualified SAP (a licensed physician, psychologist, social worker, counselor, or similar professional) evaluates you. The SAP must recommend education, treatment, or both for every driver.
- You complete the education or treatment.This can range from classes to counseling to an inpatient program. The SAP sets it based on your evaluation.
- The SAP checks your progress.If you complied, the SAP reports that to the employer and writes a follow-up testing plan.
- You take a return-to-duty test.It is directly observed. You need a negative drug result, an alcohol level under 0.02, or both, before you can drive.
- You complete follow-up testing.At least 6 unannounced tests in your first 12 months back. The plan follows you to any new carrier, and you will not be told the schedule.
Passing the steps makes you eligible to drive again. It does not make a carrier hire you back. That is the employer’s choice.
Clean record and years behind the wheel? Apply to contract with Accelerated.
How Long Return to Duty Takes
The rules set the steps, not a number of weeks. How long the education or treatment takes is up to the SAP, based on your evaluation.
Follow-up testing has a clearer clock. It lasts at least 12 months, with at least 6 tests. The SAP can extend it for up to 48 more months, so up to 5 years in all. After the first year, the SAP can also end it early.
The Clearinghouse in One Paragraph
Violations are recorded in FMCSA’s Drug and Alcohol Clearinghouse. A driver with a “prohibited” status there loses commercial driving privileges until the return-to-duty process is done. Carriers check the Clearinghouse before you drive for them and every year after. Our guide to DAC reports, PSP and MVR explains Clearinghouse queries and consent.
Owner-Operators Run Their Own Program
If you run your own authority and are your own only driver, you are both the employer and the driver under these rules. You still need random testing, in a pool of at least two drivers. FMCSA says a driver who is not leased to a carrier does this as a member of a consortium. For carriers on their own authority, see our sub-hauler program.
What Accelerated Requires
Every contract driver must be able to pass a DOT physical, a drug screen, and a background check. We also ask for:
- 3 years of CDL-A driving experience
- 1 year of verifiable 9-car experience
- A valid Class A CDL, an acceptable MVR, and a clean safety history
- A current DOT medical card
DOT Drug and Alcohol Testing FAQs
What drugs does a DOT drug test check for?
Five classes: marijuana, cocaine, opioids (including codeine, morphine, hydrocodone, oxycodone and 6-AM), amphetamines (including methamphetamine and MDMA), and PCP. The test is a lab test of a urine sample.
Does DOT test for marijuana if it is legal in my state?
Yes. The DOT says state marijuana laws have no bearing on its testing program. Its rules do not allow marijuana use by tested drivers for any reason, medical or recreational.
How often are truck drivers randomly tested?
For 2026, FMCSA’s minimum random rates are 50% for drugs and 10% for alcohol, based on the average number of driver positions. Carriers can test above those minimums.
What happens if I refuse a DOT test?
A refusal is generally treated the same as a positive test. You are removed from driving right away and cannot return until you complete the return-to-duty process with a DOT-qualified substance abuse professional.
How long is the return-to-duty process?
The rules set steps, not weeks. The SAP decides how long education or treatment takes. Follow-up testing then runs at least 12 months with at least 6 tests, and it can last up to 5 years.
Haul Cars With Accelerated
We run OEM plant, port, and rail freight across the country with contract drivers. If you have 3 years of CDL-A driving and 1 year of verifiable 9-car experience, and you can pass a drug screen, we want to hear from you.
Ready now? Apply to contract with Accelerated.
Sources
Last checked September 28, 2026. Random testing rates are set each year. This guide is a plain-language summary, not legal or medical advice. If you have a violation, follow your SAP and your employer’s process.
- 49 CFR 40.85, drug test cutoff table
- FMCSA, What substances are tested?
- DOT ODAPC, recreational marijuana notice
- FMCSA, When does testing occur?
- DOT ODAPC, 2026 random testing rates
- 49 CFR 382.301, pre-employment testing
- 49 CFR 382.303, post-accident testing
- 49 CFR 382.305, random testing
- 49 CFR 382.307, reasonable suspicion testing
- 49 CFR 382.201, alcohol concentration
- 49 CFR 382.207, pre-duty alcohol use
- 49 CFR 382.505, other alcohol-related conduct
- 49 CFR 382.103, who the rules cover
- FMCSA, What if I fail or refuse a test?
- 49 CFR 40.285, when a SAP evaluation is required
- 49 CFR 40.293, the SAP’s initial evaluation
- 49 CFR 40.305, the return-to-duty test
- 49 CFR 40.307, follow-up testing
- FMCSA Drug and Alcohol Clearinghouse
- 49 CFR 382.701, Clearinghouse queries