Modeling bus drivers' aberrant behaviors and the influences on fuel and maintenance costs

Bus drivers' aberrant behaviors such as errors and violations might bring about extra fuel consumption and mechanic abrading. To investigate how the aberrant behaviors affect the fuel and maintenance costs, seven indexes are proposed and their corresponding threshold values are determined through the field experiments. Nearly six months of en route data are collected from an intercity bus route and the raw data are converted into the proposed index values by a database management system. A collinearity test is performed and three different specifications of simultaneous-equation regression models are attempted. The results show that abnormal engine rotation, unstable speed gradient, remarkable jerk, and speeding are the four independent indexes which can significantly explain the effects of bus drivers' aberrant behaviors on fuel and maintenance costs. Based on the cost importance of these four indexes, the drivers are further clustered into five categories and some practical applications are addressed.