Citation

Tompkins SJ. Proc. Am. Assoc. Automot. Med. Annu. Conf. 1973; 17: 304-319.

Copyright

(Copyright © 1973, Association for the Advancement of Automotive Medicine)

DOI

unavailable

PMID

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Abstract

The transportation industry is faced with more than 300 vehicle safety standards proposed since 1966, when the Department of Transportation was directed to issue federal motor vehicle safety standards. The objective is to make highways safer for all users. Some 100 of the standards affect trucks; however, Federal Motor Vehicle Safety Standard (FMVSS) 121 has a greater impact on the trucking industry than any federal regulation ever. Becoming effective Sept. 1, 1974, this "braking standard" seeks to make trucks more compatible with automobiles in their braking performance: Stopping in much shorter distances than ever before and doing so without veering out of a 12- foot lane.

Larger, more powerful brakes are necessary to meet the stopping distances, and new front brakes will be required because, under the standard, about 50 percent of the braking will be done by front brakes, whereas today's heavy- duty vehicles have about 30 percent braking ability on the front. The higher deceleration levels result in a dynamic weight shift to the front axle assembly, so axles and spring must be strengthened. The requirement to stay within a 12-foot lane necessitates an anti wheel-lock device. The interaction of axles, brakes, springs and anti wheel-lock devices must be considered in meeting the requirements of the standard; thus, a total systems approach appears necessary. Herein lies the challenge, considering that there are some 800 brake and axle combinations to study, modify and test to assure compatibility.