The cast
Part 40 defines each role; Part 382 says what each one does in a reasonable suspicion test. The definitions matter because several of these people work for service agents, not for the employer, and the rule is precise about which decisions a service agent may not make.
| Role | Who it is | What they do here | Rule |
|---|---|---|---|
| Trained supervisor or company official | Anyone the employer designates to supervise drivers, after 60 minutes on alcohol misuse and 60 on controlled substances. | Observes, decides that reasonable suspicion exists, removes the driver from safety-sensitive functions, signs the written record within 24 hours. May not conduct the alcohol test. | 49 CFR 382.307(c)49 CFR 382.603 |
| DER | Designated employer representative: an employee authorized to remove drivers from safety-sensitive duties and make the required decisions in the testing process. Never a service agent. | Receives the record and the results, arranges the collection, decides employer-determined refusals, removes the driver on a violation, reports to the Clearinghouse, refers the driver to a SAP. | 49 CFR 40.349 CFR 40.23 |
| Collector | The person at the collection site who instructs the driver, inspects the specimen, and completes the custody and control form. | Runs the drug collection. Reports an insufficient specimen, a walk-out, or a refusal to try again to the DER immediately. | 49 CFR 40.349 CFR 40.193(b) |
| BAT or STT | Breath alcohol technician (evidential device) or screening test technician (screening device). | Conducts the alcohol test. Must be someone other than the person who made the determination. Notifies the DER directly of a refusal. | 49 CFR 40.349 CFR 40.261(c) |
| MRO | Medical review officer: a licensed physician who receives laboratory results and evaluates medical explanations. | Verifies the drug result, interviews the driver on a non-negative, rules on insufficient-specimen medical claims, reports verified positives and MRO-determined refusals to the Clearinghouse within two business days. | 49 CFR 40.349 CFR 382.705(a) |
| SAP | Substance abuse professional: evaluates drivers who violated a DOT rule and recommends education, treatment, follow-up testing, and aftercare. | Enters only after a violation. Evaluates the driver, sets the plan the driver must complete before a return-to-duty test, prescribes the follow-up schedule. | 49 CFR 40.28549 CFR 40.293 |
| C/TPA | Consortium or third-party administrator: a service agent that provides or coordinates testing services. Not the employer. | Books the collection, routes specimens and results, keeps copies. May receive results for the employer. Cannot act as DER or make the employer’s decisions. | 49 CFR 40.3 |
| Driver | The covered employee. | Must submit to the test. Stays off safety-sensitive functions until an alcohol test reads below 0.02 or 24 hours pass, and, after a violation, until the return-to-duty process is complete. | 49 CFR 382.21149 CFR 382.307(e)(2) |
The hand-offs, in order
Who passes what to whom
- 1. Supervisor to driver
- 49 CFR 382.307(a)–(c)
- The trained supervisor observes, decides, tells the driver a test is required, and removes the driver from safety-sensitive functions.
- 2. Supervisor to DER
- 49 CFR 382.307(f)
- The DER (who may be the same person) arranges transport and the collection, and receives the signed observation record within 24 hours.
- 3. DER to collection site
- 49 CFR 382.307(e)(1)49 CFR 40.191
- The BAT or STT runs the alcohol test, within two hours if possible; the collector runs the drug collection. Either reports refusal conduct straight back to the DER.
- 4. Laboratory to MRO
- 49 CFR 40.3
- The laboratory reports the drug result to the MRO, never to the employer. The MRO verifies it, interviewing the driver first if it is not negative.
- 5. MRO to DER
- 49 CFR 40.23(a)–(b)
- The MRO reports the verified result to the DER. On a verified positive, adulterated, or substituted result the DER removes the driver immediately, on the initial report, without waiting for paper.
- 6. DER to the Clearinghouse
- 49 CFR 382.705(b)
- The employer reports an alcohol result of 0.04 or greater and employer-determined refusals by the close of the third business day; the MRO has already reported its own results within two.
- 7. DER to SAP, and back
- 49 CFR 40.28549 CFR 382.705(b)(1)
- After any violation the driver is referred to a SAP, completes the SAP’s plan, passes a return-to-duty test, and then follows the SAP’s follow-up testing schedule. The DER tracks each milestone and reports the return-to-duty and follow-up completions.
The supervisor’s part of this sequence, with the signs to record and the clocks that start at step 1, is in the reasonable suspicion checklist.
Two roles that cannot be the same person, two that can
The rule draws exactly one hard line inside the employer: the person who makes the determination that reasonable suspicion exists to conduct an alcohol test shall not conduct the alcohol test of the driver. The observer cannot be the tester. 49 CFR 382.307(c) In practice this is rarely a problem, because the test is run by a BAT or STT at a collection site, but a carrier that keeps its own screening device must plan for a second qualified person.
Nothing in Part 40 or Part 382 keeps the trained supervisor from also being the DER, and in an owner-run fleet that is the normal arrangement: the owner observes, decides, receives the results, and makes the employer’s decisions. What the owner cannot do is hand those decisions to the consortium.
What the DER must do, and how fast
- Remove the driver from safety-sensitive functions immediately on the initial report of a verified positive, adulterated, or substituted result, or an alcohol result of 0.04 or greater. Do not wait for the written report or a split-specimen result. 49 CFR 40.23(a)–(c)
- Decide, when the collector or technician reports conduct at the site, whether it was a refusal. 49 CFR 40.191(d)(1)
- Report the violation to the Clearinghouse by the close of the third business day after learning of it. 49 CFR 382.705(b)
- Keep the driver off safety-sensitive functions until the return-to-duty process is complete. 49 CFR 382.501 49 CFR 40.23(d)
Related guides
- What is reasonable suspicion drug and alcohol testing: the whole process, start to finish.
- When a driver refuses a reasonable suspicion test: what counts as a refusal and who decides.
- What if the reasonable suspicion test comes back negative: what the DER does with a negative, dilute, or cancelled result.
- Who needs reasonable suspicion training: which supervisors must be trained, by DOT mode.
Frequently asked questions
Can the trained supervisor also be the DER?
Yes. Nothing in Part 40 or Part 382 keeps one employee from being both the supervisor trained under §382.603 and the designated employer representative. In a small carrier the owner is often both. The one combination the rule forbids is on the testing side: the person who makes the alcohol determination may not conduct the alcohol test.
Can the DER conduct the alcohol test?
Only if the DER is a qualified breath alcohol technician or screening test technician and did not make the reasonable suspicion determination. Part 40 defines the BAT and STT as the people who operate the testing devices, and §382.307(c) bars the determiner from running the alcohol test. In practice the collection site’s technician does it.
Can our C/TPA act as the DER?
No. Part 40 defines the DER as an employee authorized to remove employees from safety-sensitive duties and make required decisions in the testing process, and states that service agents cannot act as DERs. A C/TPA can coordinate collections, laboratories, MROs, and reporting, and can receive results on the employer’s behalf, but the decisions stay with an employee of the employer.
Who decides whether a driver refused the test?
It depends on the conduct. When the driver fails to appear, leaves the site before the collection is complete, or declines to try again after an insufficient specimen, the collector reports it and the employer decides whether it is a refusal. Adulterated and substituted specimens, and the lack of a medical explanation for an insufficient specimen, are refusals determined by the MRO. For alcohol, the BAT or STT documents the conduct and notifies the DER directly.
Who reports a reasonable suspicion result to the Clearinghouse?
The MRO reports verified positive, adulterated, and substituted results and the refusals the MRO determines, within two business days. The employer reports alcohol results of 0.04 or greater and the refusals the employer determines, by the close of the third business day. Negative results are not reported.
What does the SAP actually do?
A substance abuse professional evaluates a driver who has violated a DOT drug and alcohol rule, recommends education or treatment the driver must complete, and later determines whether the driver has complied before a return-to-duty test can be given. Every violation requires the SAP process; the employer cannot skip it, and the SAP’s follow-up testing plan runs for at least a year after return to duty.
Does the driver talk to the MRO?
Only when the laboratory result is not negative. The MRO contacts the driver to ask about legitimate medical explanations before verifying a positive, adulterated, or substituted result. A negative result goes from the laboratory to the MRO to the DER without a driver interview.
Sources
Every citation on this page was checked against the eCFR text current as of October 30, 2026.
- 49 CFR 40.3 — Definitions (DER, collector, BAT, STT, MRO, SAP, C/TPA)
- 49 CFR 382.307 — Reasonable suspicion testing
- 49 CFR 382.603 — Training for supervisors
- 49 CFR 382.211 — Refusal to submit to a required test
- 49 CFR 382.501 — Removal from safety-sensitive function
- 49 CFR 382.705 — Reporting to the Clearinghouse
- 49 CFR 40.23 — Employer actions after verified results
- 49 CFR 40.191 — Refusal to take a drug test
- 49 CFR 40.193 — Insufficient amount of specimen
- 49 CFR 40.261 — Refusal to take an alcohol test
- 49 CFR 40.285 — When a SAP evaluation is required
- 49 CFR 40.293 — The SAP’s initial evaluation
