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DOT Alcohol Testing Rules for Trucking Companies

DOT alcohol tests follow a strict two-step process set out in 49 CFR Part 40 and Part 382. A screening test comes first, and only a result of 0.02 or higher leads to a confirmation test. This guide explains who can run the test, what the numbers mean, and when a test is allowed.

Updated September 28, 2026 · Checked against the federal regulations

Who can conduct a DOT alcohol test

Only two kinds of trained people can run a DOT alcohol test. A Screening Test Technician (STT) runs an alcohol screening device. A Breath Alcohol Technician (BAT) runs an evidential breath testing device (EBT). Under 40.211, an STT can do only screening tests. A BAT can do both screening and confirmation tests.

Both must finish training and a set of error-free mock tests before they start. They need refresher training at least every five years (40.213). A trained supervisor should not test his or her own employee unless no other STT or BAT is available (40.211(c)). The supervisor who decides a reasonable suspicion test is needed cannot run that alcohol test (382.307(c)).

Every DOT alcohol test uses the DOT Alcohol Testing Form (ATF) under 40.225.

Screening test vs. confirmation test

The screening test is the first test. It can be done on an approved breath or saliva alcohol screening device (ASD) or on an EBT (40.229). An ASD can only be used for screening, never for confirmation.

If the screening result is under 0.02, the test is over and the result goes to the Designated Employer Representative (DER) (40.247(a)). If it is 0.02 or higher, the driver must take a confirmation test (40.247(b)).

The confirmation test must be done on an EBT by a BAT (40.231). Blood and urine alcohol tests are not allowed under Part 40 (40.277).

Wait at least 15 minutes after the screening test before the confirmation test (40.251(a)(1)).
The confirmation test should start as soon as possible, and not more than 30 minutes after the screening test.
During the wait, the driver must not eat, drink, put anything in the mouth, or belch.
The BAT must run an air blank that reads 0.00 before the confirmation test (40.253(a)).

What the results mean

Under 0.02: no action is required under DOT rules (40.255(a)(2)).

0.02 to 0.039: this is not a DOT violation, but the driver cannot do safety-sensitive work right away. Under 382.505(a), the driver is off safety-sensitive duty until the start of the next regularly scheduled duty period, but not less than 24 hours after the test. DOT rules do not let you take any other action based only on a result under 0.04 (382.505(b)). Your own company policy may still apply.

0.04 or higher: this is a violation of 382.201. The driver must be removed from safety-sensitive duty and cannot come back until finishing the return-to-duty process in Part 40, Subpart O (382.503). You must report a confirmed result of 0.04 or higher to the Clearinghouse by the close of the third business day after you get it (382.705(b)).

When alcohol tests can happen

Alcohol tests are tied to work time. A random alcohol test can only happen while the driver is doing safety-sensitive work, just before, or just after (382.305(m)). The same limit applies to reasonable suspicion alcohol tests (382.307(d)).

Separately, a driver may not do safety-sensitive work within four hours after using alcohol (382.207).

Post-accident: if the test is not done within 2 hours, write down why. If it is not done within 8 hours, stop trying and write down why (382.303(d)(1)).
Reasonable suspicion: the same 2-hour and 8-hour limits apply (382.307(e)(1)).
Reasonable suspicion with no test done: if the driver shows signs of alcohol impairment, the driver cannot do safety-sensitive work until a test shows under 0.02 or 24 hours have passed (382.307(e)(2)).

How results reach you, and when a test is cancelled

The BAT must send confirmation results straight to the DER. A result of 0.02 or higher must reach the DER right away, and it cannot be sent through a C/TPA or other service agent (40.255(a)(5)).

Some mistakes cancel a test. Examples are starting the confirmation test before the 15-minute wait ends or skipping the air blank (40.267). A cancelled test is neither positive nor negative, and it does not count toward your random testing rate (40.273).

If a driver cannot give enough breath, the employer must send the driver for a doctor's evaluation within five days. If the doctor finds no medical reason, it is a refusal to test (40.265(c)).

Pact Compliance runs random pools and keeps drug and alcohol testing records organized for small fleets and owner-operators.

Common questions

Is a 0.03 alcohol test a DOT violation?

No. A result from 0.02 to 0.039 is not a violation of 382.201. But under 382.505, the driver cannot do safety-sensitive work until the next regularly scheduled duty period, and not less than 24 hours after the test.

Can a saliva test be used for a DOT alcohol confirmation?

No. Saliva devices can be used only for screening. Confirmation tests must be done on an evidential breath testing device (EBT) by a BAT (40.229 and 40.231).

Can my company supervisor give the alcohol test?

Only if the supervisor is a trained STT or BAT, and even then not for his or her own employee unless no other STT or BAT is available (40.211(c)). The person who made a reasonable suspicion decision cannot run that alcohol test (382.307(c)).

How long do we have to do a post-accident alcohol test?

Test as soon as practicable. If it is not done within 2 hours, keep a record of why. After 8 hours, stop trying and keep a record of why (382.303(d)(1)).

Can a random alcohol test happen on a driver's day off?

No. Under 382.305(m), a driver can only be tested for alcohol while doing safety-sensitive work, just before, or just after.

Sources

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