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United States Department of Transportation United States Department of Transportation

CMVRTC: Continued Analysis of PBBT Brake Performance Evaluation Data

Goal:

To continue gathering Level 1 brake performance stroke measurements and correlate those stroke measurements with performance-based brake tester (PBBT) brake force measurements on each wheel end and for the total vehicle.

Background:

Currently the PBBT brake performance measurement device can be used to determine the overall vehicle brake performance of CMVs. States currently utilizing a PBBT have expressed concern that some cargo-carrying CMVs when tested on the PBBT can barely pass the minimum overall vehicle performance criteria of 43.5 percent brake efficiency, and many times have several individual wheel-ends with values significantly below the 43.5 percent brake efficiency value. The Oak Ridge National Laboratory (ORNL) has conducted CMV stopping distance testing and the effect on stopping distance is significant when specific wheel ends have very low or no measurable brake performance.

Summary:

This work will continue to focus on gathering Level 1 brake performance stroke measurements and correlating those stroke measurements with PBBT brake force measurements on each wheel end, and for the total vehicle. ORNL will continue to analyze data to correlate brake stroke length measurements with PBBT wheel-end brake force values. This data will be used to support future rulemaking efforts to develop a CMV PBBT brake performance individual wheel end criteria, and a revised overall vehicle brake performance measurement.

Outcomes:

Analysis of brake inspection data; identification of additional data/data analysis needs; briefing for the Commercial Vehicle Safety Alliance (CVSA) PBBT Users Group Meeting; letter report on findings.
 

Milestones:

Completed:

October 2017: Kick-off meeting.
January 2018: Literature review of PBBT and CMV brake performance testing complete.
March 2018: Draft guidance document complete.
June 2018: Final briefing.
August 2018: Final report complete.

Funding:

FY17 Funding: $75,000

Project Manager:

For more information, contact Luke Loy of the Policy Division at 202-366-0676 or Luke.loy@dot.gov.

Contractor:

Oak Ridge National Laboratory
Last updated: Monday, January 8, 2018