_Agenda_Packet_092826 - Laserfiche WebLink

24 Corners and Curb Radii Pedestrian safety and comfort is enhanced by smaller curb radii, which shorten crossing distances for pedestrians and reduce vehicle turning speeds. However, streets must accommodate large turning vehicles, including school buses and transit vehicles, which require larger turning radii. One of the most challenging aspects of intersection design is determining methods of accommodating large vehicles while keeping intersections as compact as possible. This requires engineering judgment, as each intersection is unique in terms of the number of travel lanes, presence of a median, and a number of other features that fundamentally impact corner design. Guidance Curb radii should be designed to accommodate the intended design vehicle, or the most frequent user of a given street, turning using one approach lane and one receiving lane, as well as the intended control vehicle, or an infrequent larger vehicle, turning using multiple lane spaces. Considerations • The design and control vehicle are context dependent. Common design vehicles include a DL-27 for local streets, SU-30 for downtown and commercial streets, and BU-40 for designated bus routes. Control vehicles are often larger trucks like a WB- 50. • At signalized intersections, corner design should assume that a large vehicle will use the entire width of the receiving lanes on the intersecting street. • Depending on an agency’s encroachment policy, it may be possible to allow a large turning vehicle to encroach on the adjacent travel lane on the departure side (on multi-lane roads) to make the turn. • Mountable truck aprons can be implemented to deter design vehicles from making higher-speed turns, while accommodating control vehicles without encroachment or off-tracking into pedestrian areas. Mountable truck aprons should be visually distinct from the adjacent travel lane and sidewalk. (For more information, refer to Truck Aprons section).