Evaluation of the Effect of Road Shoulder Characteristics on Dynamic Parameters Affecting on Vehicle Rollover in the joint of Shoulder-roadway in Horizontal curves

A large number of vehicle rollovers occur in horizontal curves. Designing the shoulders appropriately may reduce the number of these kinds of accidents. Therefore, this study aims at exploring the influence of shoulder characteristics on the rate of rollover accidents. Also, lateral acceleration and drivers’ behavior is analyzed considering the effects of shoulder characteristics at curves. The characteristics considered in this research are width, transverse slope, and pavement. To conduct this research, dynamic simulation is used. The number of scenarios that are indeed the number of observations is 324. Two linear regression models are developed with their dependent variables being the rollover rate and the lateral acceleration. The independent variables are shoulder characteristics, vehicle dynamics (vehicle speed) and driver behavior (encroachment angle into centerline in Degree) and different types of vehicles (Sedan, SUV, and Truck). The results indicate that the shoulder characteristics significantly affect the safety in terms of the roll rate and the lateral acceleration of the vehicles. This effect differs among the different types of vehicles and is measured by the dynamic and structural characteristics of the vehicles. The results of this research are useful for designing safer roads as well as the road safety audit.