Citation

Haney J. HSRI Res. Rev. 1979; 9(6).

Copyright

(Copyright © 1979, University of Michigan Highway Safety Research Institute)

DOI

unavailable

PMID

unavailable

Abstract

Views and opinions are presented which are based on findings over a significant number of years on motor vehicle mechanics research and the braking performance of heavy trucks and tractor-trailers. Specific issues identified in the Advance Notice of Proposed Rulemaking (ANPRM) are addressed. The discussion provides insight into certain conflicts and compromises between the general requirements for heavy vehicle braking and the development of practical braking and stability, and one standard for all commercial vehicles versus the variety of vehicle configurations in use. Comments on the ANPRM are presented in a series of questions and responses: Should the seventeen requirements remaining in FMVSS-121 (as listed in Docket 79-03) be retained or should they be suspended or abolished in their entirety? Do the requirements that remain without the presence of an antilock system, compromise the stability of heavy commercial vehicles? Should a 60-mph stopping distance requirement be reinstated in orde to prevent depowering of brakes? Should the Administration consider stopping distance requirements that are different for various test conditions, and in particular, should special considerations be given to the "bobtail" condition? Should the Administration consider promulgation of standards that would permit the demonstration of compliance using test procedures in which wheel lockup is permitted as long as the vehicle can be retained within a 12-foot lane?