How is the Accident Rate calculated?

In this article

• How is the Accident Rate calculated?
• How might the Accident Rate affect a motor carrier? 

How is the Accident Rate calculated? 

Accident Rate is also called Accident Frequency Factor by FMCSA. These terms are interchangeable. This is a calculation of the number of accidents a motor carrier experiences per 1 million miles. The FMCSA has set thresholds of 1.5 or less to be considered satisfactory for most motor carriers. Urban Carriers who operate within a 150-air mile radius have a 1.7 threshold.
 

The calculation:
(Number of DOT recordable accidents in last 12 months x 1,000,000) / (total miles driven in the Past 12 months)

The fewer the DOT recordable accidents the better. It is important to review your accident register and determine if you can get any moved to not preventable. This can be done per the FMCSA if the accident is any of the 21 Crash Preventability Determination Program (CPDP) criteria. If a crash fits one of the documented criteria, it can be submitted to the program for removal. Only crashes that happened on a public highway, that involved a tow, injury or fatality should be in the DOT reportable accident count.

In order to improve the denominator of the equation, motor carrier's should report all applicable miles. The FMCSA uses the MCS-150 for the miles reported. This includes miles on lease agreements - even if not reported on an IFTA. This should include owner operator miles, short term lease agreements, and any miles associated with a vehicle over 10,000 pounds.

How might the Accident Rate affect a motor carrier? 

An accident rates is a key indicator of a motor carrier’s overall safety performance. During an FMCSA on-site audit, the first metric reviewed is the carrier’s accident rate. If the math formula of the Accident Rate is unsatisfactory, the carrier automatically receives a Conditional rating—regardless of performance in other compliance areas such as drug and alcohol testing, driver qualification files, or hours-of-service policies.

A Conditional rating can significantly harm business operations. Most broker boards will avoid or remove carriers with this status from load assignments until the rating is upgraded. Although FMCSA offers a process to request a rating change, it is lengthy—often taking six months or more. Carriers must prepare and submit an appeal demonstrating corrective actions, but initial appeals are frequently denied due to insufficient evidence of improvement. This often forces carriers to reapply after more time has passed to show sustained compliance.

Underwriters also consider accident ratings when evaluating risk. While the FMCSA rating system is rigid, underwriters may independently assess whether the rating accurately reflects the carrier’s risk profile. In some cases, underwriters decline coverage based solely on these FMCSA metrics, even if their own assessment suggests a lower risk.