Citation

Campbell KL. HSRI Res. Rev. 1977; 8(23).

Copyright

(Copyright © 1977, University of Michigan Highway Safety Research Institute)

DOI

unavailable

PMID

unavailable

Abstract

In late 1975, the Highway Safety Research Institute (HSRI) of the University of Michigan began a 30-month study designed to assess the safety impact of Federal Motor Vehicle Safety Standard No. 121, Air Brake Systems. This standard, which became effective in March, 1975, requires substantial changes in the braking capabilities of air-braked vehicles. The study entails collecting, for the calendar years 1976 and 1977, data on the mileage and accident involvements of trucks manufactured before and after the standard became effective, and then comparing those data. Secondary objectives of the study are to compare the maintenance and operational experiences of the pre- and post-standard vehicles during the study period. One of the purposes of the interim report on which this article is based is to provide all interested parties with a better idea of the study design, the problems associated with acquiring consistent and reliable field data, and the methods being employed. The mid-point findings show that 121-equipped vehicles have slightly lower accident rates and slightly higher maintenance rates, but neither of those differences is statistically significant.