A transit bus operator who drives a revenue service vehicle is classified as a safety sensitive employee under federal transit law. That classification triggers a specific drug and alcohol testing structure built from two regulations working together: 49 CFR Part 655, the Federal Transit Administration rule that decides who must be tested and when, and 49 CFR Part 40, the Department of Transportation rule that controls how every test is collected, analyzed, and verified. A transit agency, a contracted bus operating company, or a small paratransit provider all answer to the same two rules once they meet the coverage test. This guide explains who that test actually catches, what testing has to happen and when, which panel applies, and how a transit employer or contractor builds a program that holds up.
Who Is Actually Covered
Part 655 reaches recipients and subrecipients of certain Federal Transit Administration financial assistance that have employees performing a safety sensitive function, plus the contractors those recipients use to perform that function. A safety sensitive function under the rule includes operating a revenue service vehicle whether or not it is in revenue service, operating a nonrevenue service vehicle when required to hold a commercial driver license, controlling dispatch or movement of a revenue service vehicle, maintaining a revenue service vehicle or equipment used in revenue service, and carrying a firearm for security purposes. Coverage turns on the funding relationship and the job function, not on the size of the agency, so a small city bus system or a rural paratransit contractor that receives qualifying federal transit assistance is covered in the same way a large metropolitan authority is. An agency that receives no such assistance and operates a bus fleet entirely on local funds may fall outside Part 655, though it can still owe drug and alcohol testing duties under a different federal rule if its drivers hold a commercial driver license and operate in interstate commerce, or under state or local law. Agencies that are unsure which category they fall into should read the definitions in Part 655 directly rather than assume either way, since misclassifying coverage in either direction creates real liability.
The Six Testing Circumstances
Part 655 sets out the testing events a covered transit employer must run, and Part 40 governs how each one is collected and processed. The circumstances are pre employment, random, post accident, reasonable suspicion, return to duty, and follow up. A transit agency assembling a DOT pre employment drug screening kit program needs every one of these six built into written policy, not just the ones that come up most often.
| Testing event | When it applies | Key feature |
|---|---|---|
| Pre employment | Before an applicant first performs a safety sensitive function | Must have a verified negative result on file before duty begins |
| Random | Unannounced, spread reasonably through the year | Minimum annual percentage rates are set by the FTA Administrator and change from time to time, so a transit employer should confirm the current rate on the official federal transit source rather than a fixed number |
| Post accident | After a qualifying accident as defined in Part 655 | Strict time windows apply to both the drug and alcohol specimen; testing must stop if not completed within the regulatory window |
| Reasonable suspicion | Trained supervisor observes specific, contemporaneous signs | Requires documented observations and completed supervisor training |
| Return to duty | Before a safety sensitive employee resumes duty after a violation | Directly observed collection and a Substance Abuse Professional evaluation first |
| Follow up | After return to duty, for a period set by the Substance Abuse Professional | At least six tests in the first year, with no advance notice to the employee |
Each of these events is described in detail in Part 655 Subpart E, Types of Testing. The post accident window is one of the most commonly missed pieces of the rule. If the alcohol test is not administered within the regulatory window after the accident, the employer has to document why and stop attempting it; the same discipline applies to the drug test window. A breath alcohol testing device kept on site or with a trained technician shortens the gap between the accident and the test, which matters because the clock does not pause for travel time to a clinic.
The Panel: DOT 5 Panel Plus Expanded Opiates, and Alcohol
Transit drug testing under Part 40 uses the federal drug testing panel maintained under the Department of Health and Human Services mandatory guidelines, commonly called the DOT 5 panel: marijuana metabolites, cocaine metabolites, amphetamines, phencyclidine, and opioids, with the opioid category expanded in recent years to pick up additional semi synthetic opioid metabolites beyond the original codeine and morphine markers. A transit employer sourcing 5 panel drug test cups for a collection site should confirm with the laboratory which specific analytes and cutoffs are in use, since cutoff levels and confirmatory methods are set in Part 40 and can be updated by HHS. Alcohol testing runs on a separate track using a screening device followed, when the screening result is 0.02 or higher, by a confirmation test on an evidential breath testing device operated by a trained breath alcohol technician. Many transit collection sites keep both a drug test cup for the urine specimen and a dedicated breath device on hand so a single collection event can cover both drug and alcohol testing without sending the employee to two locations. Background on who may run the breath portion of that collection and what certification a technician needs is covered in Breath Alcohol Technician Certification Requirements Under DOT Rules.
Medical Review Officer and Substance Abuse Professional Roles
Every laboratory confirmed positive, adulterated, substituted, or invalid drug test result under Part 40 must be reviewed by a Medical Review Officer before the employer ever sees it as positive. The Medical Review Officer interviews the employee, reviews prescription documentation for any legitimate medical explanation, and only reports a verified positive once that review is complete. This process, along with the specific grounds a Medical Review Officer may use to cancel or verify a result, sits in Part 40 Subpart G, Medical Review Officers and the Verification Process. A separate role, the Substance Abuse Professional, takes over once an employee has a verified violation. The Substance Abuse Professional evaluates the employee, refers them to education or treatment, and must determine the employee has complied before a return to duty test can even be scheduled; this evaluator cannot be the same person who treats the employee. The full sequence, including the directly observed collection requirement for the return to duty test, is in Part 40 Subpart O, Substance Abuse Professionals and the Return to Duty Process. A transit agency building this step into its program for the first time can walk through the full sequence in The DOT Return to Duty Drug Test Process: A Step by Step Guide for Employers.
What a Non DOT Panel May Add Under Separate Authority
Part 655 and Part 40 set a floor, not a ceiling, and they do not give an employer permission to substitute a broader company panel for the federally required test. What a transit agency can do, under its own employment policy or applicable state law rather than under DOT authority, is run a separate non DOT test for substances the federal panel does not cover, such as an expanded panel that screens additional prescription classes, or a company alcohol policy with a lower action threshold than the federal 0.04 cutoff for safety sensitive duty. The two tests have to stay clearly separated. A non DOT specimen cannot be collected on a federal Custody and Control Form, a non DOT laboratory result cannot be reported as a DOT result, and an employer cannot tell a Medical Review Officer to apply DOT cancellation or verification rules to a non DOT specimen. Agencies that want a supplemental alcohol screen on top of the federal breath test, for example after a complaint rather than an accident, often add an alcohol test strip as part of a separate non DOT policy, documented and administered apart from the Part 655 program.
Building a Compliant Program, Small Agency or Contractor
A small transit agency or a contractor running buses under someone else's federal grant still needs every piece of the full program, just scaled to its size. The basics: a written policy that lists every safety sensitive job title and spells out all six testing circumstances; a Designated Employer Representative who can receive test results and remove an employee from safety sensitive duty immediately on a verified positive; a random testing selection method that is genuinely unannounced and spread through the year, often run through a third party administrator serving a pool of several small transit employers so the random draw has statistical integrity; trained supervisors who have completed reasonable suspicion training before they are ever asked to make that call; a collection site with proper dip card or cup supplies, chain of custody forms, and a trained collector; and a record keeping system that can produce documentation on request. Many small agencies and contractors join a consortium or use a third party administrator rather than build a standalone random testing program, which the rule allows and which usually produces a more defensible random draw than a single small employer running its own pool. A transit employer new to federal contracting can review the broader framework for setting up compliant transportation testing in DOT drug and alcohol testing supplies for transportation companies before finalizing a policy.
The Substance Abuse and Mental Health Services Administration maintains the federal framework behind the drug testing side of these programs, including laboratory certification and the mandatory guidelines that set panel analytes and cutoffs; agencies building a program from scratch can review that framework on the SAMHSA workplace programs page. The random testing rate itself is not fixed in the regulation text. The FTA Administrator publishes minimum annual percentage rates for drug and alcohol testing, and those rates can be adjusted based on industry wide positive rates, so a transit employer should check the current published rate through the Federal Register listing for the Federal Transit Administration rather than rely on a number printed in an older policy or article.
Frequently asked questions
Does every transit bus driver fall under Part 655?
Only drivers employed by, or contracted to, a recipient or subrecipient of qualifying federal transit assistance who perform a safety sensitive function such as operating a revenue service vehicle. A bus operation funded entirely outside that federal transit assistance structure may not be covered by Part 655, though other federal, state, or local testing duties may still apply.
What drugs does the transit testing panel cover?
The federal panel used for transit testing covers marijuana metabolites, cocaine metabolites, amphetamines, phencyclidine, and opioids, with an expanded opioid category that reaches beyond the original codeine and morphine markers. Exact analytes and cutoff levels are set in the Department of Health and Human Services mandatory guidelines referenced by Part 40 and should be confirmed with the testing laboratory.
Is there a minimum random testing rate for transit employees?
Part 655 requires random testing at a minimum annual percentage rate that the FTA Administrator sets and can change, so the specific percentage in effect at any point should be confirmed through the official Federal Transit Administration source rather than assumed from a prior year.
Can a transit agency add tests beyond the federal panel?
A transit agency may run a separate non DOT test under its own policy or applicable state law for substances or circumstances the federal rule does not reach, but that test has to be kept entirely separate from the DOT specimen, forms, and laboratory process, and cannot be reported as a DOT result.
Who decides if a positive result gets reported to the employer?
A Medical Review Officer reviews every nonnegative, adulterated, substituted, or invalid laboratory result, including any prescription documentation the employee provides, before a verified result goes to the employer. The employer never receives a raw laboratory result directly.
What has to happen before a transit employee can return to safety sensitive duty after a violation?
A Substance Abuse Professional must evaluate the employee, confirm compliance with any recommended education or treatment, and determine the employee is ready before a directly observed return to duty test can be scheduled and verified negative.
This article is general information for transit employers and contractors, not legal advice. Transit agencies should confirm current coverage, panel requirements, and random testing rates against the official Federal Transit Administration and eCFR sources and consult qualified counsel before finalizing a drug and alcohol testing policy.
