49 CFR Part 382: Testing, Clearinghouse, and Employer Duties

49 CFR Part 382 is the federal regulation that governs drug and alcohol testing for every driver who holds or needs a commercial driver’s license, and for every employer of those drivers. Enforced by the Federal Motor Carrier Safety Administration, it sets who must be tested, when testing is required, what substances and behaviors are prohibited, and what has to happen before a driver who violates the rules can get back behind the wheel.¹

Who the Rule Covers

Part 382 applies to anyone who operates a commercial motor vehicle in interstate or intrastate commerce and is required to hold a CDL or commercial learner’s permit, and to every employer of those drivers, including federal, state, and local government agencies.²

A vehicle falls under the rule if it has a gross combination or single-vehicle weight rating of 26,001 pounds or more (including a towed unit over 10,000 pounds), is designed to carry 16 or more passengers including the driver, or hauls loads of any size that require hazardous materials placards.

Self-employed owner-operators are not exempt. Under Part 382, an owner-operator is both employer and driver and must join a testing consortium to satisfy random testing, since a person cannot randomly select themselves.²

Some CDL holders sit outside Part 382 because separate regulations exempt them: active-duty military and National Guard personnel operating CMVs for military purposes, farmers and farm employees moving agricultural products under the CDL farm exemptions, operators of firefighting and other emergency vehicles, and drivers responding to pipeline or winter heating fuel emergencies under specified conditions. Drivers already covered by Federal Transit Administration or Federal Railroad Administration testing programs are also excluded, because they meet equivalent requirements under their own agencies.²

The rules don’t only apply while you’re driving. A “safety-sensitive function” covers all on-duty time, from the moment work begins or you’re required to be ready to work until you’re fully relieved. That includes waiting to be dispatched, inspecting or servicing the vehicle, loading and unloading, supervising loads, handling shipment paperwork, attending a disabled vehicle, and all time in or on the vehicle except in a compliant sleeper berth.³ Every prohibition below applies across that full span, not just at the wheel.

What’s Prohibited

The alcohol rules turn on two thresholds. At 0.04 or above, a driver has committed a federal violation. No driver may report for duty or remain on duty performing safety-sensitive functions at that concentration, and no employer may allow it.⁴ A result at that level triggers immediate removal, Clearinghouse reporting, and a mandatory evaluation before commercial driving can resume.

Between 0.02 and 0.039 the consequence is lighter. The driver is pulled off all safety-sensitive duties until the next regularly scheduled shift and in no case less than 24 hours after the test. Part 382 does not treat this range as a formal violation, and employers cannot impose Part 382 discipline based on it alone, though a company’s own policy may do so.⁵

Timing rules apply on top of the thresholds. A driver cannot perform any safety-sensitive function within four hours of consuming alcohol. After an accident that triggers post-accident testing, no alcohol for eight hours or until the post-accident test is complete, whichever comes first.⁶

Controlled substances are flatly prohibited during safety-sensitive functions, with one narrow prescription exception. A driver may use a prescribed controlled substance (other than Schedule I drugs) only if a licensed medical practitioner familiar with the driver’s medical history has specifically advised that the medication will not impair safe operation of a commercial vehicle.⁷ A standard prescription is not enough on its own. The prescribing doctor must know the patient drives commercially and must affirmatively clear the drug for that use.

Marijuana is prohibited regardless of state law. Even after the DEA rescheduled certain marijuana-related products in April 2026, the DOT testing framework under 49 CFR Part 40 did not change. A positive test for THC is still a verified positive, a Medical Review Officer cannot accept a state medical marijuana card as a legitimate medical explanation, and the driver faces the same consequences as any other drug violation.

When Testing Is Required

Part 382 mandates testing in six situations, each with its own trigger and timing.

Pre-Employment

Before a new driver performs any safety-sensitive function, the employer must have a verified negative controlled substances test in hand. The driver cannot start until that result comes back.⁸ There is a limited exception when the driver participated in a compliant program within the previous 30 days and was either tested within the past six months or was in a random pool for the past 12 months. Pre-employment alcohol testing is not federally required, though some employers add it under their own policy.

Post-Accident

Testing is required after a CMV crash on a public road in commerce under specific conditions. If someone dies, every surviving driver performing safety-sensitive functions must be tested for both alcohol and drugs, whether or not a citation is issued.⁹ In non-fatal crashes, testing is required only if the driver receives a moving traffic citation and the crash caused either bodily injury requiring immediate off-scene medical treatment or disabling vehicle damage requiring a tow. Without that citation, federal law does not require post-accident testing even after a severe crash.

Timing is tight. The alcohol test must be completed within eight hours and the drug test within 32 hours. Delays past two hours must be documented, and if the windows close entirely the employer must document why and stop testing.

Random

Employers must maintain a random testing program that selects drivers using a scientifically valid method. For 2026, the minimum random drug testing rate is 50 percent and the minimum random alcohol testing rate is 10 percent of the average number of driver positions.¹⁰ FMCSA can adjust these rates year to year based on industry violation data.

Reasonable Suspicion

When a trained supervisor directly observes specific physical, behavioral, speech, or performance signs of alcohol or drug use during, just before, or just after a driver’s safety-sensitive functions, the employer must require a test. A hunch is not enough. The supervisor must document concrete indicators, and must have completed at least 60 minutes of training on alcohol misuse plus 60 minutes on controlled substance use to make the determination.¹¹

Return-to-Duty and Follow-Up

After a violation, a driver cannot resume any safety-sensitive function until a return-to-duty test comes back negative. Once back, the driver faces a minimum of six unannounced follow-up tests in the first 12 months. The Substance Abuse Professional directing the process can order more frequent testing during that year and extend the follow-up schedule for up to 48 additional months, for a possible five-year total.¹²

Refusing a Test Counts as a Violation

A refusal carries the same consequences as a verified positive: Clearinghouse reporting, immediate removal, and the full SAP evaluation process before returning to work.¹³

Refusal is broader than saying no. It also includes failing to show up for a test, leaving the collection site before finishing the process, failing to provide an adequate specimen without a valid medical explanation, and tampering with a sample. DOT now recognizes both urine and oral fluid collection as approved methods, and the employer chooses which to use. Refusing the specific method the employer selected is itself a refusal, even if the driver would agree to the other.

What the Drug Test Screens For

DOT drug tests screen for five substance categories, and employers cannot add or remove any of them:

Marijuana (THC)
Cocaine
Opioids, including oxycodone and hydrocodone
Amphetamines, including MDMA
Phencyclidine (PCP)

Each class has federally set cutoffs for initial screening and confirmatory testing.¹⁴ A result below the initial cutoff is reported negative. A result at or above it goes to confirmatory testing, and only a confirmed positive moves forward for verification.

As of 2026, DOT recognizes urine and oral fluid collection as equivalent methods, with the employer deciding which to use. Oral fluid collection is inherently observed, which eliminates the same-gender direct observation protocols that apply to certain urine-based tests.

How Results Are Verified

A laboratory positive is not automatically reported to the employer. Every confirmed positive first goes to a Medical Review Officer, a licensed physician with specialized substance abuse training. The MRO or a trained assistant contacts the driver confidentially for a medical review interview. That interview is the driver’s chance to present a legitimate medical explanation, such as a valid prescription from a practitioner who knows the driver’s job and has cleared the medication for commercial driving.

If the MRO accepts the explanation, the result is reported to the employer as negative. If not, the MRO reports a verified positive. The employer never sees prescription details or medical information, only the final determination. Missing the MRO’s call or failing to respond within 72 hours can result in the positive being verified without the driver’s input.

The FMCSA Drug and Alcohol Clearinghouse

The Clearinghouse is a federal database that tracks drug and alcohol violations across the commercial driving industry. Employers must report verified positives, refusals, and other violations by the close of the third business day after learning of them.¹⁵ Substance Abuse Professionals report evaluation completions, and employers report negative return-to-duty results and completion of follow-up testing.

Every employer must run a full Clearinghouse query before hiring a driver and must run annual queries on all current drivers. A violation record stays visible until all four of these conditions are met: the SAP has reported evaluation and treatment completion, the employer has reported a negative return-to-duty test, the current employer has confirmed all follow-up tests are complete, and five years have passed since the violation date.¹⁶ A driver who never completes the return-to-duty process will have the violation visible indefinitely.

A major expansion, commonly called Clearinghouse II, took effect on November 18, 2024. State licensing agencies must now query the Clearinghouse before processing any CDL or CLP transaction, including renewals, transfers, and upgrades, and must deny the transaction if the query returns a prohibited status. When FMCSA notifies a state that a driver is prohibited, the state has 60 days to downgrade the CDL. Once the driver clears the return-to-duty process and FMCSA notifies the state, the state must make the driver eligible for reinstatement.¹⁷

What Happens After a Violation

When a driver violates the alcohol or drug prohibitions, the employer must immediately remove the driver from all safety-sensitive functions, with no waiting period. An employer who keeps a known-violating driver in service faces civil penalties that are adjusted annually for inflation.

Federal law requires the employer to remove the driver and initiate the return-to-duty process. It does not require the employer to take the driver back, and many carriers simply terminate the employment relationship. The driver then completes the process independently if they want to drive commercially again for anyone.

The return-to-duty sequence starts with a Substance Abuse Professional evaluation. The SAP is a specific credential, not any counselor or therapist. The SAP prescribes education or treatment, then reevaluates the driver and, if satisfied, authorizes a return-to-duty test. That test must come back negative before the driver performs any safety-sensitive work, and follow-up testing begins on return.

In practice, the driver often bears the cost. SAP evaluations run roughly $200 to $600 nationally, with specimen collection fees on top. Federal regulations do not specify whether the employer or the driver must pay for the SAP evaluation and return-to-duty test. Some employers cover it under a last-chance agreement; many do not.

Employer Duties Beyond Ordering Tests

Employers carry administrative obligations under Part 382 that extend past testing itself. Every supervisor who may need to make a reasonable-suspicion determination must complete the required two hours of training, split equally between alcohol and controlled substance indicators.¹¹

Records follow a set schedule. Verified positive results, refusals, and SAP reports must be retained for five years. Negative and canceled results must be kept for one year. Employers who want to stand down a driver based on a preliminary lab positive before MRO verification must apply to FMCSA for a specific waiver, since the default rule bars removing a driver on an unverified laboratory result.¹⁸

Clearinghouse compliance is its own audit exposure. Missing the annual query on a current driver or the three-business-day reporting window for a violation creates a separate compliance problem, independent of the underlying testing issue.¹⁵

1
Federal Motor Carrier Safety Administration. Overview of Drug and Alcohol Rules for Employers
2
eCFR. 49 CFR 382.103 – Applicability
3
eCFR. 49 CFR 382.107 – Definitions
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eCFR. 49 CFR Part 382 – Controlled Substances and Alcohol Use and Testing – Section 382.201
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eCFR. 49 CFR 382.505 – Other Alcohol-Related Conduct
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eCFR. 49 CFR Part 382 – Controlled Substances and Alcohol Use and Testing – Section 382.209
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eCFR. 49 CFR 382.213 – Controlled Substances Use
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eCFR. 49 CFR 382.301 – Pre-Employment Testing
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eCFR. 49 CFR 382.303 – Post-Accident Testing
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U.S. Department of Transportation. 2026 DOT Random Testing Rates
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eCFR. 49 CFR 382.603 – Training for Supervisors
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eCFR. 49 CFR 40.307 – Follow-Up Testing Requirements
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eCFR. 49 CFR 382.211 – Refusal to Submit to a Required Alcohol or Controlled Substances Test
14
U.S. Department of Transportation. DOT Rule 49 CFR Part 40 Section 40.85
15
Federal Motor Carrier Safety Administration. What Is the Timeframe in Which an Employer Must Submit a Report
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eCFR. 49 CFR 382.719 – Availability and Removal of Information
17
Federal Motor Carrier Safety Administration. Clearinghouse SDLA FAQs – November 2024
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eCFR. 49 CFR Part 382 – Controlled Substances and Alcohol Use and Testing – Section 382.119