Job change rate as a crash predictor for interstate truck drivers.

This research analyzed the Motor Carrier Management Information System (MCMIS) database to develop estimates of the increased risk of crash involvement experienced by commercial drivers who change jobs frequently. These analyses quantified the risk of single- and multiple-crash involvement as a function of annual job change rate, and expressed the relative risk for drivers with more versus fewer job changes through calculation of the "odds ratio" statistic. Significant odds ratio values were found, indicating that crash risk begins to rise when a driver has averaged more than two jobs with different employers each year for 2 years or longer, and that the odds of being involved in multiple crashes more than doubles for drivers with three or more jobs per year during this same interval. Opportunities for further research, focusing on variables that could be extracted from existing data sources to further enhance the validity and predictive value of the relationships found in this study, were also identified.