In a series of ongoing posts, we’ve been examining the rather stringent testing program put in place by the Federal Motor Carrier Safety Administration to combat the problem of impaired driving among licensed commercial motor vehicle operators.

Indeed, our first two posts on this subject discussed how the agency calls for mandatory drug screening for prospective drivers, random alcohol and drug testing for all bus drivers, and compulsory alcohol and drug testing in the wake of an accident.

In today’s post, the final in this series, we’ll explore what happens when random testing yields a positive result for alcohol, or any one of five controlled substances (methamphetamine / amphetamine, marijuana, opiates, cocaine or PCP).

What if the urinalysis results are positive?

If the driver’s test comes back positive, the administering laboratory will report their findings to a medical review officer (MRO), who will then contract the driver directly to share the results and inquire as to whether there are any mitigating factors behind the positive result. If not, the MRO will report the findings to the driver’s employer.

What happens next?

As you might imagine, the driver is immediately removed from service, meaning they cannot operate a CMV on any public roadways. Furthermore, their employer will furnish them with a directory of substance abuse professionals (SAP) who can help them start the “return-to-duty” process, which must be completed before the driver can return to driving a CMV in any legal capacity.

What happens upon completion of the “return-to-duty” process?

The SAP who helped the driver complete the “return-to-duty” process and signed the necessary report must prescribe a minimum of six random, direct observed substance abuse tests to be performed sometime during the first 12 months of the driver’s passing of the “return-to-duty” test, which measures their ability to perform safety sensitive functions like driving a CMV.

Once these six tests are performed, do things revert to the norm for the driver?

Not necessarily. Assuming the driver is employed, the SAP can call for random follow-up tests for up to five years.

If you have suffered serious personal injuries or lost a loved one in a bus accident attributable to the reckless conduct of a driver or company, please consider speaking with an experienced legal professional.

Trial attorney F. Braxton “Brack” Terry focuses his law practice on representing injured people in a wide range of personal injury claims, including cases involving truck crashes, car accidents, defective products, premises liability, and more. His efforts have secured significant verdicts and settlements, including over $20 million for a large group of plaintiffs, and recoveries of $5.3 million, $4.1 million, $3.6 million, $3.1 million, $2.49 million, and high-six-figure amounts for individuals.

Brack has received numerous professional honors from prestigious organizations. Most recently, he was named “Lawyer of the Year” by Best Lawyers® for Personal Injury Litigation in Knoxville in 2026. He has been listed in Best Lawyers® every year since 2013 and by Super Lawyers since 2009. Brack has been a member of the Multi-Million Dollar Advocates Forum since 2007.

Brack earned his law degree from the Nashville School of Law in 1996. In addition to membership in the Tennessee Bar, he is admitted to practice before the U.S. District Court for the Eastern District of Tennessee and the U.S. Court of Appeals for the 6th Circuit. Brack is a member of many professional organizations, such as the Tennessee Trial Lawyers Association, the American Association for Justice, and the Interstate Truck Litigation Group.

Admitted to Tennessee Bar: 1996
Years of Legal Experience: 30
Listed in The Best Lawyers in America®: 2013-Present
Listed as a Mid-South Super Lawyer: 2009-Present