Modification and Partial Validation of the Driver/Vehicle Module

Four assumptions of the Driver/Vehicle Module of the Interactive Highway Safety Design Model were tested against data obtained in two on-road studies of driver behavior. Supported were assumptions that drivers track to the inside of horizontal curves and that a linear control model is adequate for describing steering behavior. Not supported were assumptions of consistent preferred lateral acceleration in horizontal curves and consistent preferred longitudinal accelerations and decelerations during curve approach and exit. Experimental results support (a) an analytically derived square-root relationship between preferred lateral acceleration and curvature and (b) an analytically derived square-root relationship between longitudinal acceleration or deceleration and total speed change.