Bounds on effectiveness of driver hours-of-service regulations for freight motor carriers

Crash rates for trucks depend in part on the length of time drivers have been operating their vehicles. This paper investigates bounds on the reduction in crash rates due to the imposition of hours-of-service regulations, which limit the number of hours drivers operate their vehicles. Methods for analyzing probability distributions for trip length, and odds ratios for crashes (as a function of hours driven) are developed. We also produce bounds on the economic costs of truck-involved collisions, and estimate changes in these costs due to changes in hours-of-service rules. The study is a first step toward a broader cost/benefit analysis of regulations, based on analysis of data from the fatal accident reporting system (FARS).