Abstract
Generally, traffic accidents are influenced by variables including road geometry, roadside design, and traffic conditions. To prevent accidents and provide comfortable driving environment it is necessary to understand how accidents relate to conditions of geometry and appurtenance. This study developed (1) a traffic accident frequency prediction model based on geometric and appurtenance conditions on urban highways, and (2) a traffic accident severity model to analyze influencing factors at urban highways. These models developed may be helpful for the design of safe highways. Additionally, it may identify the potentially hazardous factors on existing highways, and contribute to traffic safety improvement.