A New Evaluation Methodology For Measuring Highway Safety Using a Microscopic Traffic Simulator

Abstract

Highways are designed to maintain the speeds that satisfy most of the drivers using the facility. Consideration in design should be given to the type and characteristics of the drivers expected to use the highway. For safety on highways the designer applies the minimum design criteria that drivers can control the operations of their vehicles to avoid accident. The safety of vehicles on highways is, however, subject to the driver's ability, training, and experience. It means that the safety of the highway could be different depending on the driver's behavior. This paper addresses the methodology of evaluating highway safety in the viewpoint of driver's behavior and suggests the maximum speed limit on the highway. In general, the safety of roadways is evaluated by criteria based on achieving driving consistency. Lamm suggests three types of safety criteria which are closely related to the curvature change rates of the single curve: achieving design consistency, achieving operating speed consistency, and achieving driving dynamic consistency. Table 1 summarized the recommended ranges for design levels for three types of safety criteria. The primary measurements of safety are the possibilities of rear-end accident, high speed, abrupt change of acceleration and deceleration speed of individual vehicles on his driving. The safety of vehicles on highways is evaluated as following safety indices.