Effects of Truck Driver Wages and Working Conditions on Highway Safety: Case Study

Abstract

The role of human capital and occupational factors in influencing driver safety has gained increased attention from trucking firms and policy makers. The influence of these factors, along with demographic factors, on the crash frequency of truck drivers is examined. A unique driver-level data set from a large truckload company collected over 26 months was used for estimating regression models of crash counts. On the basis of estimates from a zero-inflation Poisson regression model, results suggest that human capital and occupational factors, such as pay, job tenure, and percentage of miles driven during winter months, have a significantly better explanatory power of crash frequency than demographic factors. Relative to the zero-inflation and count models, results suggest that higher pay rates and pay increases are related to lower expected crash counts and to a higher probability of no crashes, all else held equal. Although the data come from one company, the evidence provided is a first step in examining the structural causes of unsafe driving behavior, such as driver compensation. These results may motivate other companies to modify operations and driver hiring practices. Also, the need for a comprehensive study of the relationship between driver compensation and driver safety is demonstrated.