HIGHWAY GEOMETRIC DESIGN CONSISTENCY EVALUATION SOFTWARE

Previous research has concluded that horizontal curves on which design speeds are less than drivers' desired speeds exhibit operating speed inconsistencies that increase accident potential, and that current AASHTO design policy is unable to identify and address. One step to address these concerns is the development by the FHWA of an Interactive Highway Safety Design Model that incorporates a consistency module. A Highway Geometric Design Consistency Program has been developed to serve as a basis for this consistency module. The program is a menu-driven microcomputer procedure for evaluating horizontal alignment consistency on rural two-lane highways using two preliminary models: an operating speed profile model and a driver workload profile model. This paper reviews these preliminary models, describes the menu-driven procedure for using them, and recommends future development of the models and procedure.