Truck travel increased from 668 billion vehicle km (400 billion vehicle mi) of travel to 1,002 billion vehicle km (600 billion vehicle mi) from 1980 to 1989, a staggering 50 percent increase. If this trend continues, truck travel will exceed 1.67 (1 trillion vehicle mi) trillion vehicle km by the end of year 2000. This increase poses operational and safety problems for both passenger vehicles and trucks. To improve the safety of existing highway facilities, an understanding of the relationship between truck accidents and the geometry of the highway is required. The objectives of this study were to identify the roadway variables that affect truck accidents and to develop mathematical models of their relationships. Data from the Highway Safety Information System were used in this analysis.

The Highway Safety Information System is a new database developed by the Federal Highway Administration. It contains accident, roadway, and Traffic data from five states. Models for truck accidents on Interstate and two-lane rural roads were developed using data from the state of Utah. The interstate model indicates that truck accidents are primarily affected by horizontal curvature and horizontal gradient. For two-lane rural roads, the model indicates that truck accidents are affected by the shoulder width and the horizontal curvature. Gradient was not found to have an effect on truck accidents on two-lane roads, although this may be because of inadequate data.

Yusuf M. Mohamedshah, Jeffrey F. Paniati, and Antoine G. Hobeika. Truck Accident Models for Interstates and Two-Lane Rural Roads, Transportation Research Record 1407, TRB, National Research Council, Washington D.C., 1993