In practice
Say a CDL driver tests positive on a random drug test. They're taken off driving immediately and show as prohibited in the Clearinghouse. To get back behind the wheel, they find a DOT-qualified SAP, who evaluates them and recommends a program, such as an education course or counseling. When the SAP confirms they completed it, the driver takes a directly observed return-to-duty test. A negative result clears them to drive again.
It doesn't end there. The SAP sets a follow-up plan: at least 6 unannounced tests in the first 12 months back on duty, and possibly more for up to 5 years. EXAMPLE: a driver back at work in March could face 6 or more tests before the following March, at times they don't know in advance.
Source: 49 CFR 40.307(d), (e) · checked Oct 2026
Source: 49 CFR 382.309; 40.305 · checked Oct 2026
The process is the same for company drivers and owner-operators. An owner-operator's consortium handles the employer side, including the follow-up tests; see the DOT drug testing consortium guide. What happens to the license itself is covered in will my CDL be suspended if I fail a drug test.
Questions
Who can be a SAP?
A licensed professional, such as a physician, psychologist, social worker or certified addiction counselor, who meets DOT's SAP training and qualification rules. The SAP works for the process, not for you or your employer: their job is to evaluate and recommend, not to advocate.
Can I skip the SAP if I quit driving for a while?
No. The requirement doesn't expire with time off. Before you can do safety-sensitive work for any DOT employer again, you must complete the SAP process and pass a return-to-duty test, and the follow-up plan follows you to new employers.
Starting out?
New to trucking rules? Start with truck driver training programs and the truck driver job outlook, or check whether a truck needs a CDL at all with the Do I need a CDL checker.