This paper describes the evolution of the curve warning system for drivers in the U.S. and contrasts it with the curve warning systems used in some European countries. The paper states and discusses the main requirements of a curve warning and delineation system. Experiments and their results aimed at the determination of the human visual curve radius perception accuracy as a function of the number of delineation devices (chevrons) and the resulting delineation rules are discussed. OCARD (ODOT Computer Aided Road Delineation), a knowledge based software package for the application and placement of curve delineation devices according to a number of delineation rules, mainly based upon geometric and human factors aspects, is discussed. The knowledge based system, developed with regard to easy human-computer interaction, assists the user in the delineation tasks and treats similar or equal curves with the same traffic characteristics, in exactly the same, consistent and uniform way. The computed curve and delineation information can be stored and easily distributed, if required. OCARD can be used in the office or in the field if it is installed on a laptop PC. (A)
Samenvatting