Project Goal

The objective of this study was to assess whether there is a relationship between the duration of CMV driver medical certification (the maximum 24 months versus less than 24 months) and driver safety performance. Medical Examiner’s Certificate (MEC), Form MCSA-5876, data reflecting the length of medical certification from the National Registry of Certified Medical Examiners (National Registry) and crash and inspection violation data from the Motor Carrier Management Information System (MCMIS) were used to evaluate the relationship between the duration of CMV drivers’ medical certification and crash and/or violation risk.

Background

FMCSA relies on the certified medical examiner (ME) to assess and determine if the commercial motor vehicle (CMV) driver meets the physical qualification requirements cited in 49 CFR 391.41. The maximum time a medical examiner can certify a driver is 2 years. The ME can, however, certify for a period of time less than 2 years. Drivers with specific medical conditions require more frequent certification. For example, drivers with the following conditions can only be certified for a maximum of 1 year per the regulatory requirements: (1) drivers grandfathered under 391.64 as part of the original vision waiver program; (2) drivers with insulin-treated diabetes mellitus and qualified under the diabetes standard; and (3) driving in exempt intra-city zone If the ME determines that a condition requires more frequent monitoring, the ME may certify the driver for 3 months, 6 months, 1 year, or any other timeframe that is less than 2 years.

Summary

Overall, the longer the MEC length, the less likely drivers are to have a crash or driver-related violation. However, it would be premature to conclude that drivers with MEC lengths of less than 24 months are more likely to have a crash or inspection violation than drivers with 24-month certification, as the specific medical condition and any possible treatment were unknown. Also, crash data in the MCMIS dataset are not coded for fault, and thus there is no way to know if the driver or the driver’s medical condition played any role in the cause of a crash. A future study should analyze data on why a driver received less than 24-month medical certification.

Contractor

VTTI

Final Report

The brief and report have been published in the National Transportation Library:
https://rosap.ntl.bts.gov/view/dot/66621
https://rosap.ntl.bts.gov/view/dot/66620