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The U.S. Department of Transportation (DOT) requires employers in regulated transportation industries to test employees who perform safety-sensitive work for drugs and alcohol. The rules say who must be tested, when, and how. This section explains them in plain language and links to the regulation text.
Who is covered
DOT testing applies to safety-sensitive employees of employers regulated by a DOT agency: commercial drivers who need a CDL (FMCSA), aviation (FAA), railroad (FRA), public transit (FTA), and pipeline (PHMSA) workers. The U.S. Coast Guard applies the same procedures to maritime workers. If you are not sure whether your company or an employee is covered, see Who is subject to DOT drug and alcohol testing?.
Start here
| Topic | What you will find |
|---|---|
| DOT drug and alcohol testing basics | Test types, the 5-panel drug test, alcohol limits, refusals, the MRO, the return-to-duty process, and what the employer must do. |
| FMCSA Drug and Alcohol Clearinghouse | Queries, driver consent, reporting, and return to duty for CDL drivers, and how Med-Stop helps. |
| DOT program resources | Official DOT and FMCSA guidance on testing and random rates. |
How the rules fit together
- 49 CFR Part 40 sets the testing procedures for every DOT agency: collections, laboratories, MRO review, alcohol testing, refusals, SAPs, and confidentiality. See 49 CFR Part 40 reference.
- 49 CFR Part 382 is the FMCSA rule for CDL drivers and their employers: who must be tested, when, prohibited conduct, recordkeeping, training, and the Clearinghouse. See 49 CFR Part 382 reference.
- Other DOT agencies have their own "who and when" rules that also use Part 40 procedures: FAA (14 CFR Part 120), FRA (49 CFR Part 219), FTA (49 CFR Part 655), PHMSA (49 CFR Part 199), and the Coast Guard (46 CFR Parts 4 and 16).