The short answer
If you employ drivers who need a CDL, federal rules require a drug and alcohol testing program under 49 CFR part 382 (FMCSA) carried out by the procedures in 49 CFR part 40 (DOT). Before a new driver performs safety-sensitive work, you need a verified negative pre-employment drug test and a full query of the FMCSA Drug & Alcohol Clearinghouse. After that, run at least an annual Clearinghouse query on every driver, keep drivers in a random testing pool, test after qualifying accidents and on reasonable suspicion, and report violations to the Clearinghouse.
Who is covered
Part 382 applies to employers of drivers who operate commercial motor vehicles that require a CDL on public roads, and to those drivers (49 CFR 382.103). Owner-operators count as both employer and driver. The rules cover “safety-sensitive functions,” which include driving and also time spent inspecting, loading or waiting to be dispatched while on duty.
Other DOT agencies, such as the FAA, FRA, FTA and PHMSA, have their own testing rules that also use part 40 procedures. This guide focuses on FMCSA-regulated motor carriers.
The six FMCSA test types
| Test | When it happens | Rule |
|---|---|---|
| Pre-employment | Before a driver performs safety-sensitive functions for the first time. A verified negative drug result is required. Alcohol pre-employment testing is optional. | 49 CFR 382.301 |
| Post-accident | After accidents that meet the FMCSA criteria, such as a fatality, or a citation combined with an injury requiring medical treatment away from the scene or a vehicle towed away. | 49 CFR 382.303 |
| Random | Unannounced, selected by a scientifically valid method from a pool. FMCSA sets minimum annual rates; for 2026 they are 50% of average driver positions for drugs and 10% for alcohol. | 49 CFR 382.305 |
| Reasonable suspicion | When a trained supervisor observes specific, contemporaneous signs of drug or alcohol use. | 49 CFR 382.307 |
| Return-to-duty | Before a driver who violated the rules goes back to safety-sensitive work, after completing the substance abuse professional (SAP) process. | 49 CFR 382.309 |
| Follow-up | Unannounced tests after return to duty, on the schedule the SAP sets. | 49 CFR 382.311 |
How a DOT drug test works (49 CFR part 40)
The 5-panel
DOT drug tests use a fixed panel set by part 40. Employers cannot add or remove drugs:
- Marijuana metabolites
- Cocaine metabolites
- Amphetamines (amphetamine, methamphetamine, MDMA, MDA)
- Opioids (codeine, morphine, 6-acetylmorphine, hydrocodone, hydromorphone, oxycodone, oxymorphone)
- Phencyclidine (PCP)
Collection, lab and MRO review
Collection
A trained collector follows part 40 procedures and the federal custody and control form, typically with a split urine specimen.Laboratory testing
The specimen goes to a laboratory certified by HHS for an initial screen and, if non-negative, confirmation testing.Medical Review Officer
A licensed physician MRO reviews lab results and talks with the donor about any legitimate medical explanation before verifying the result.Result to employer
The employer receives the verified result. Only verified results are acted on.
The FMCSA Drug & Alcohol Clearinghouse
The Clearinghouse is FMCSA's online database of CDL drivers' drug and alcohol program violations. Employers, medical review officers, substance abuse professionals and others report violations to it, and employers must query it. Its requirements are in subpart G of part 382 (49 CFR 382.701 to 382.727).
Queries employers must run
- Pre-employment full query before a driver performs safety-sensitive functions. The driver must give specific electronic consent in the Clearinghouse, so they need their own Clearinghouse account (49 CFR 382.701(a)).
- Annual query on every driver you employ, at least once a year. A limited query, with a general written consent that can cover multiple years, satisfies this (49 CFR 382.701(b)).
- Escalation: if a limited query shows information exists, you must run a full query within 24 hours. If you cannot, the driver may not perform safety-sensitive functions until you do.
What employers must report
- Alcohol test results of 0.04 or higher and refusals to test (other than drug test refusals, which the MRO reports)
- Actual knowledge of on-duty or pre-duty alcohol use, alcohol use after an accident, or controlled substance use
- Negative return-to-duty test results and completion of follow-up testing
MROs report verified positive, adulterated and substituted drug test results.
Prohibited status and CDL downgrades
A driver with a violation and no completed return-to-duty process is in “prohibited” status and may not perform safety-sensitive functions. Since November 18, 2024, FMCSA rules require state driver licensing agencies to remove CDL privileges from drivers in prohibited status until they complete return-to-duty.
A DOT hiring checklist for motor carriers
Get consent
Have the driver register in the Clearinghouse and grant electronic consent for the full pre-employment query.Run the full query
Confirm the driver is not in prohibited status.Order the pre-employment drug test
Wait for a verified negative result before any safety-sensitive work.Check the driving record
Order an MVR check as part of driver qualification. State fees may apply.Verify past employment
Confirm prior employers with employment verification, alongside the safety performance history the FMCSRs require.Enroll in a random pool
Add the driver to your random testing pool or a consortium/third-party administrator pool.Calendar the annual query
Set a reminder to query every driver at least once every 12 months.
For more on screening drivers, see our transportation screening page.
Frequently Asked Questions
Who has to follow FMCSA drug and alcohol testing rules?
Employers of drivers who operate commercial motor vehicles requiring a commercial driver's license (CDL) on public roads, and the CDL drivers themselves, are covered by 49 CFR part 382. That includes owner-operators, who must meet both the employer and driver requirements.
What drugs does a DOT drug test screen for?
The DOT 5-panel test under 49 CFR part 40 covers marijuana metabolites, cocaine metabolites, amphetamines (including methamphetamine and MDMA), opioids (including codeine, morphine, 6-acetylmorphine, hydrocodone, hydromorphone, oxycodone and oxymorphone) and phencyclidine (PCP). Employers may not add other drugs to a DOT test.
Does a Clearinghouse query replace a pre-employment drug test?
No. Before a driver performs safety-sensitive functions for the first time, the employer must receive a verified negative pre-employment drug test result and must also run a full Clearinghouse query. They are separate requirements.
What is the difference between a full query and a limited query?
A full query shows the details of any violation in the Clearinghouse and requires the driver's specific electronic consent inside the Clearinghouse. It is required for pre-employment. A limited query only shows whether information exists, can be done with a general written consent, and satisfies the annual query requirement. If a limited query shows information, the employer must run a full query within 24 hours or remove the driver from safety-sensitive duty.
Can an employer use a DOT test for non-DOT employees?
No. DOT testing procedures and forms are only for employees covered by DOT rules. Employees who are not DOT-regulated should be tested under a separate non-DOT program.
Sources
Work with SaffHire
SaffHire offers DOT-compliant and non-DOT drug screening, with collection at Labcorp patient service centers Nationwide.
SaffHire is a Veteran-Owned background screening company based in Frisco, TX, serving employers Nationwide. It was founded by Robert Krebsbach, John Waak and Jody Thigpen. There are no minimums and no setup fees, data is protected with bank-level encryption, and the employer portal is available 24/7.
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This article is general information, not legal advice. Talk to your employment counsel about your specific situation.