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.

Modeling animal-vehicle collisions using diagonal inflated bivariate Poisson regression

“…In this situation, zero-inflated models, such as zero-inflated Poisson and zero-inflated NB, have been used for modeling such collision data sets (Shankar et al, 1997;Garber and Wu, 2001;Lee and Mannering, 2002;Kumara and Chin, 2003;Miaou and Lord, 2003;Rodriguez et al, 2003;Shankar et al, 2003;Noland and Quddus, 2004;Qin et al, 2004;Lord et al, 2005a,b). However, Lord et al (2005a,b) and Warton (2005) have argued that considerable caution should be exercised when applying zeroinflated models to crash data because a true two-state process may not exist.…”

A multivariate Poisson-lognormal regression model for prediction of crash counts by severity, using Bayesian methods

“…There also has been considerable interest in models that allow for excessive zeros, such as zeroinflated Poisson (ZIP) and zero-inflated negative binomial (ZINB) regression approaches (see, e.g., Lord et al 2005;Shankar et al, 1997;Garber and Wu, 2001;Lee and Mannering, 2002;Kumara and Chin, 2003;Miaou and Lord, 2003;Rodriguez et al 2003;Shankar et al 2003;Noland and Quddus, 2004;Qin et al, 2004).…”

Management's attitudes toward safety in commercial vehicle operations

“…Among factors that are less examined, yet still critical, are the psychological and sociological factors within organizations such as motivations and incentives (Rodrigues, Rocha, Khattak, & Belzer, 2003;Rodrigues, Targa, & Belzer, 2006). Based on the current body of knowledge, there appears to be an increasing awareness of organizational and individual attitudes and beliefs that may influence crash likelihood even before a driver enters a vehicle (Clarke, 1999;Short, Boyle, Shackelford, Inderbitzen, & Bergoffen, 2007;Wills, Watson, & Biggs, 2006).…”