It’s no secret to anyone in trucking that highway transportation is one of the heaviest regulated industries in the United States. The Federal Motor Carrier Safety Administration is the federal agency charged with that regulation.

For years, its primary enforcement mechanism for ensuring that regulated carriers comply with the multitude of safety-related regulations has been the compliance review, or safety audit. Because FMCSA is a sub-agency of the Department of Transportation, it’s commonly called a DOT audit.

There are few things more nerve-wracking for a motor carrier, and for good reason.

For one, the stakes couldn’t be higher. 

A DOT audit can result in significant fines, a downgraded safety rating, and even a company-wide out-of-service order, depending on the nature and extent of regulatory violations uncovered.

And when the FMCSA selects a carrier for an audit, or an investigation, the fleet typically only has 48 hours to prepare.

No motor carrier expects to be audited, and most do little to prepare until it’s too late. But simply understanding the process goes a long way toward ensuring a positive outcome should an audit ever come.

How the FMCSA Prioritizes Motor Carriers for Audits

The FMCSA is a relatively small agency, even though it is tasked with regulating nearly 600,000 carriers and millions of commercial drivers across the country. That means the agency lacks the personnel to audit a significant percentage of regulated carriers at any regular interval. Accordingly, it has to prioritize carriers for audit. 

Understanding what factors the agency uses to prioritize carriers for audit is important to understand.

Since 2010, the FMCSA has relied primarily on its Compliance, Safety, Accountability (CSA) program, and more specifically, its Safety Measurement System (SMS), to prioritize carriers for audits.

High CSA Scores Can Prompt a DOT Audit

SMS is a system that scores all regulated motor carriers using data gathered through roadside inspections, crashes, and investigations within the past 24 months. Violations discovered through inspections and/or investigations are assigned to one of seven categories known as BASICs, and then weighted, based in part on their severity and how recently they occurred. 

Each carrier's performance is then evaluated against similarly situated motor carriers in each BASIC, and the carrier is assigned a percentile score in each BASIC.

Ultimately, carriers who perform worse than a certain percentage of their peers and exceed certain “intervention thresholds” in one or more BASICs in a given month will be higher on the agency's list for a potential audit.

FMCSA uses the Safety Measurement System as its workload-prioritization tool to identify carriers for interventions and investigations.

What FMCSA calls "high-risk carriers" are more likely to be targeted for an audit. These are carriers meeting particularly stringent SMS criteria — generally two or more of four specified BASICs at or above the 90th percentile for two consecutive months.

So it's imperative that carriers closely track their scores and take deliberate steps to keep them in check.

Serious Crashes Can Lead to a DOT Audit

If the purpose of federal and state motor carrier safety regulations is to reduce highway accidents and resulting injuries, it should come as no surprise that accidents tend to trigger DOT audits. 

But not just any accidents. It’s typically the more serious accidents, especially fatalities, that prompt the FMCSA to take a closer look. This is particularly true in areas of the country where DOT investigators have more capacity to conduct these investigations.

Something to keep in mind with accident-related audits is that they tend to start out more focused in nature. For example, the agency may only request compliance documents for the driver involved in the accident.

However, these types of audits frequently transform into more comprehensive audits, particularly when the accidents garner publicity.

Safety Complaints Can Cause FMCSA to Investigate

Yet another common trigger for a DOT audit is a complaint made against the motor carrier. The FMCSA explicitly solicits safety-related complaints on its website, and it tends to take them seriously. 

It’s not uncommon for disgruntled employees to file these complaints and prompt a DOT audit, even when their complaints have no real basis in fact. Regardless, carriers should take care to thoroughly investigate any internal complaints they receive before they blossom into a full-blown DOT audit.

FMCSA Investigations Can Take Many Forms

The FMCSA conducts several types of audits: comprehensive, focused, onsite, offsite, new entrant, etc. Historically, it has favored onsite, comprehensive reviews; however, more recently, the agency has turned to offsite audits to extend its enforcement reach.

The primary benefit of these offsite reviews, of course, is they allow the agency’s investigators to review documents from their own offices, cutting down the time and expense of traveling to and from a carrier’s terminal, and relying, instead, on the electronic transfer of documents from the carrier.

Prior to the COVID-19 pandemic, the agency typically reserved these offsite reviews for less intensive circumstances, such as new entrant safety audits and focused reviews — those involving a lower volume of paperwork. However, as the offsite review process became more streamlined and reliable, the agency slowly began to ramp them up. 

During the COVID-19 pandemic, the agency sharply increased the number and scope of offsite reviews. In fact, FMCSA amended its regulations to authorize the issuance of safety fitness determinations — previously reserved for onsite reviews — following an offsite audit.

Whether onsite or offsite, an audit can focus on one or a few areas of compliance (such as hours of service), or it can be comprehensive, meaning the agency is looking at all major areas of a carrier’s compliance program. 

Occasionally, the agency will start an audit as a focused review but expand the scope based on violations discovered early on. Carriers should not be lured into a false sense of security if they learn their review will be focused in nature.

There's a Detailed Method to FMCSA Investigations

What many carriers don’t realize is that FMCSA investigators follow a very specific and methodical process when conducting their reviews. What’s more, this methodology — known as the Electronic Field Operations Training Manual or eFOTM — is available for all to access, if you can stomach the 1,082-page read.

The manual details the sample sizes that agency investigators are supposed to follow when selecting records to review. For example, eFOTM prescribes a sample of 80 driver files for a fleet with between 501 and 1,200 drivers. The manual also describes the steps investigators should take to understand the carrier’s safety management program and confirm it’s sufficient under the circumstances.

DOT audits can lead to the issuance of a safety rating and/or civil penalties

DOT safety ratings (aka safety fitness determinations) are reflections of a motor carrier's compliance with the Federal Motor Carrier Safety Regulations as of the date of the FMCSA audit that resulted in the rating. The agency only issues safety ratings to carriers that have undergone a comprehensive on- or off-site compliance review.

There are three possible ratings: Satisfactory, Conditional, and Unsatisfactory. If an audit reveals substantial enough non-compliance, the carrier will receive an Unsatisfactory rating, which will ultimately result in the carrier being shut down.

Aside from the regulatory consequences, safety ratings can also have commercial consequences, since they are publicly available through the FMCSA's online SAFER database.

The FMCSA determines a carrier's safety rating in accordance with the detailed safety rating methodology contained in Appendix B to 49 C.F.R. Part 385.

Once a carrier is selected for a comprehensive audit, the investigator evaluates and rates the carrier's compliance in six broad factor areas:

• General compliance (parts 387 and 390 of the FMCSRs);
• Driver (parts 382, 383, and 391 of the FMCSRs);
• Operational (parts 392 and 395 of the FMCSRs);
• Vehicle (parts 393 and 396 of the FMCSRs);
• Hazardous materials (part 397 of the FMCSRs and parts 171, 177, and 180 of the HMRs)
• Accidents (based on the carrier's calculated accident rate).

Each factor rating depends on the number of “acute” and/or “critical” violations the investigator uncovers within those factors.

Once the investigator completes the audit, he or she will tally the number of acute and/or critical violations in each of the six factor areas and assign a safety rating according to a particular formula.

Carriers who receive a less-than Satisfactory rating have a couple of options to upgrade that rating, including through an administrative appeal or by taking prompt action to correct admitted deficiencies.

Aside from safety ratings, audits can also lead to civil penalties. The agency routinely assesses penalties following audits, particularly for more serious violations. In 2021, the agency closed 2,771 civil penalty cases for a total of $18.37 million and an average of $6,629 per case.

The consequences of a bad DOT audit are severe, so carriers should take proactive steps to prepare. At minimum, this should include ensuring compliance records are up to date and in order.

Editor's Note: This article was published in April 2022 and reviewed for accuracy, with minor updates, in August 2026.