4T-Intersection Safety

 The Intersection Safety course was developed to discuss the issue of safety as it relates to traffic studies and plan design. Despite improved intersection design and more sophisticated applications of traffic engineering measures, the annual toll of human loss due to motor vehicle crashes has not substantially changed in more than 25 years. Perhaps with a better knowledge behind the crash statistics and countermeasures, designers can implement designs with better intersection safety. This course will brief the reader on national highway safety statistics. It will also discuss the difference between nominal and substantive safety. Human factors as related to intersection safety will be covered. Design of intersections for older drivers is also covered. There is a review of prediction of safety at intersections and provide a crash rate equation. Equations for crash frequency models for stop control of minor intersections are provided. Roadway geometrics as they relate to intersection design will be discussed. Red light running is be discussed and ideas to increase the likelihood of stopping are be provided. Screening techniques and countermeasures will be covered. A six step crash mitigation process is provided to identify high crash locations and identify countermeasures. The designer can use these steps to identify sites with potential safety problems, identify contributing factors and determine appropriate countermeasures to be used in plans preparation. The countermeasures are discussed in detail and include signing, pavement marking, lighting and signalization features. The course is designed to provide a basic knowledge of intersection safety from which an engineer can use this information in traffic studies and plan design.