An intersection is the area where two or more streets join or cross at‐grade. The intersection includes the areas needed for all modes of travel: pedestrian, bicycle, motor vehicle, and transit. Thus, the intersection includes not only... more
An intersection is the area where two or more streets join or cross at‐grade. The intersection includes the areas needed for all modes of travel: pedestrian, bicycle, motor vehicle, and transit. Thus, the intersection includes not only the pavement area, but typically the adjacent sidewalks and pedestrian curb cut ramps. The intersection is defined as encompassing all alterations (for example, turning lanes) to the otherwise typical cross‐sections of the intersecting streets. Intersections are a key feature of street design in four respects: Focus of activity ‐ The land near intersections often contains a concentration of travel destinations. Conflicting movements ‐ Pedestrian crossings and motor vehicle and bicycle turning and crossing movements are typically concentrated at intersections. Traffic control ‐ At intersections, movement of users is assigned by traffic control devices such as yield signs, stop signs, and traffic signals. Traffic control often results in delay to users traveling along the intersecting roadways, but helps to organize traffic and decrease the potential for conflict. Capacity ‐ In many cases, traffic control at intersections limits the capacity of the intersecting roadways, defined as the number of users that can be accommodated within a given time period. This chapter describes the considerations and design parameters for intersections. The chapter begins by outlining definitions and key elements, and then describes the characteristics of intersection users, intersection types and configurations, capacity and quality of service considerations, geometric design elements, and other considerations.