One of the prerequisites for a safe motion of any vehicle along a prescribed road surface is that adequate Stopping Sight Distance (SSD) is provided at every point along the roadway. Existing design policies do not fully incorporate current vehicle technology trends when providing various design values. One of these technologies is the Anti-block Brake System (ABS), with which all modern vehicles are equipped. In effect, this negligence leads to an underestimation of the abilities of SSDs of modern cars and consequently to expensive road designs. Therefore, an investigation of the actual braking distances of a medium sedan passenger car, taking into consideration the current industrial provisions for this type of car, was carried out based on a computational model developed for this case. The computed model's SSD outputs for various initial speed values were compared with existing field measurements, where no significant difference was found, proving thus the reliability of the developed computational model. The immediate effect of the derived new SSD values is a significant reduction regarding the required radii for crest vertical curves and a relevant increase of the speed limit on left curved divided highways.
Abstract