Search Results

This research paper builds onto the wealth of technical information that has been published in the past by engineers such as Flick, Radlinski, and Heusser. For this paper, the pushrod force versus chamber pressure data published by Heusser are supplemented with data taken from brake chamber types not reported on by Heusser in 1991. The utility of Heusser's braking force relationships is explored and discussed. Finally, a straightforward and robust method for calculating truck braking performance, based on the brake stroke measurements and published heavy truck braking test results, is introduced and compared to full-scale vehicle test data.

Manufacturers of new commercial vehicles (CVs) sold in the U.S. must certify that the vehicle meets safety standards for braking capability via stopping performance tests (FMVSS 121). However, for the remaining 10- to 20-year service life of that CV, the carrier is responsible for ensuring that it is maintained in safe operating condition, under regulations codified in 49 CFR 393 and 396. The origin of these Federal Motor Carrier Safety Regulations (FMCSRs) for braking safety of in-use vehicles can be traced back to 1936, with the first publication of stopping performance requirements. However, due to the logistic challenges of conducting stopping performance tests, such tests are seldom performed on in-use vehicles. As such, research was conducted in the 1950s through the 1980s to find an equivalent method, via inspection of brake system components, to that of the performance-based regulations for identifying vehicles that were considered unsafe for travel on the public roadways.