Last reviewed Oct 26, 2026. General information, not legal advice.
A DOT drug test is a drug test that federal transportation rules require. It is not the same as a test your employer picks on its own. The rules decide who gets tested, when, and how the test is done.
Who needs a DOT drug test?
DOT testing covers people in “safety-sensitive” jobs in transportation. The biggest group is commercial truck and bus drivers who need a CDL. Other covered jobs include some workers in aviation, rail, transit, pipelines and maritime.
If you are not sure whether your job is covered, ask your employer. Your employer should know which of its jobs fall under DOT rules.
When do DOT tests happen?
For CDL drivers, the common reasons for a test are:
- Pre-employment: before you start driving for a new employer.
- Random: your name is picked at random during the year.
- Post-accident: after certain crashes.
- Reasonable suspicion: a trained supervisor sees signs of drug or alcohol use.
- Return-to-duty and follow-up: after a violation, before and after you go back to work.
How is a DOT drug test done?
A DOT drug test is a urine test. The steps are set by federal rules so every test is done the same way:
- You show a photo ID.
- You wash your hands and give a sample in a private restroom.
- The collector checks the sample and seals it in front of you.
- You both sign a federal custody and control form.
- The sample goes to a lab for testing.
A medical review officer (a doctor) reviews the result before it goes to your employer.
How is it different from a non-DOT test?
A non-DOT test follows the employer’s own policy. The employer chooses the panel, like a 5-panel or 10-panel test. A DOT test must follow the federal steps exactly. You can read more in our guide to DOT vs. non-DOT testing.
Getting tested
Bring a photo ID and any paperwork from your employer. See what to bring to a drug test, or learn about our DOT drug testing.