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United States Department of Transportation United States Department of Transportation

Understanding the Safety Impacts of Electronically Controlled Brake Systems in Commercial Motor Vehicles

Project Goal:

To perform an in-depth literature search for data or modeling to determine the impact of brake-by-wire systems on safety (e.g., reduced crashes, injuries, and fatalities).


Brake-by-wire systems provide electronic activation of all braking system components. These systems rely on the use of electronically-controlled communications systems already existing within single-unit trucks and between the towing vehicle and trailer.

Brake-by-wire enhances braking precision, whereas conventional braking shortens braking distance. Furthermore, brake-by-wire systems offer potential safety benefits due to their advanced integration with antilock braking systems, electronic stability control systems, and similar electronically-controlled technologies. Finally, EBS manufacturers (such as WABCO) cite significant cost savings associated with implementation of brake-by-wire systems, due to optimized wheel brake lining wear and other maintenance-related benefits.


The National Highway Traffic Safety Administration’s (NHTSA’s) Federal Motor Vehicle Safety Standard (FMVSS) 121 requires use of a pneumatic system for foundation brakes. NHTSA has already done some feasibility testing on brake-by-wire systems. By quantifying the safety impacts of such systems, FMCSA may be able to persuade NHTSA to revise FMVSS 121 to allow for brake-by-wire systems in commercial vehicles, potentially increasing the safety of such vehicles on public roads.

Outcome: Final Report




October 2019: Final Program Management Plan


August 2020: Mid-Project Briefing


January 2021: Draft Final Report


February 2021: Final Report


March 2021: Final Briefing



       Total Funding: $ 349,727.00

Project Manager:

       Brian Routhier


            Virginia Tech Transportation Institute

Last updated: Tuesday, August 25, 2020