USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

CMVRTC: Brake Variability Analysis & Related Research

Project Goal:

To further research on the variability of brake performance in Automated Driving System (ADS) CMV operations. FY2020 research proposes to test a minimum of two FMCSA (SAE Level 2) tractor trailer combinations to provide a new dataset of brake performance data to ADS technology providers and to State and Federal agencies.


As part of the CMV Roadside Technology Corridor (CMVRTC), previous FMCSA brake performance testing has shown wide variability in full braking capacity stopping distance performance based on brake variances on the steer, drive, or trailer axles and the amount of weight carried by the tractor semitrailer. Working with Oak Ridge National Laboratory (ORNL), the agency has developed a Real Time Dynamic Brake Assessment (RTDBA) protocol to evaluate loaded vehicle brake performance characteristics, which will assist ADS CMV developers and, in the future, trucking fleets in knowing an ADS-equipped CMV's braking capabilities in real-time for safe operations.


This project is focusing on conducting additional research on the variability of brake performance for two of the Agency’s (SAE Level 2) tractor semitrailer combinations. Additional 20 and 60 mile-per-hour stopping distance testing is planned on being performed on the tractors, utilizing two types of brake friction material and conducting additional brake performance testing intervals followed by light burnishing to slowly approach a full burnished brake condition. Brake performance will also be evaluated at varying gross vehicle weights and at various brake application pressures, to develop and evaluate the Real Time Dynamic Brake Assessment (RTDBA) protocol.




 Contractor: Oak Ridge National Laboratory