Many factors must be considered when determining the corner radii of intersections. They include: availability of right-of-way, angle of intersection, pedestrian use, vehicle speeds, and the width and number of lanes. Right-turn traffic dictates the size of the outside corner radius. Consider whether there is significant volume of right-turn trucks and buses. Radii of 15 to 25 feet are typically used at minor cross streets without significant truck and bus traffic.
Where buses and large trucks turn frequently, corner radii of 40 feet or more should be provided. Very large radii (more than 40 feet) often create problems for the placement of traffic signals and other traffic control devices or increase the vehicle turning speed which is not favorable in areas with significant pedestrian use.