Bicyclist- and Pedestrian-Only Roundabouts

Transportation agencies are designing roundabouts dedicated to bicycles and pedestrians, and sometimes bicycles only, on shared-use paths. This article describes the advantages of these roundabouts and highlights some examples of their implementation. Shared-use paths and their associated roundabouts serve bicyclists, walkers, joggers, skaters -- virtually all nonvehicle traffic--and usually supplement on-road bicycle facilities. Shared-use paths typically are located alongside riverbanks, oceanfronts, canals, abandoned or active railroad and utility rights-of-way, and limited-access freeways; on college and university campuses; and in parks and on connectors between parks. The roundabouts are particularly useful and effective when bicycle volumes are relatively high. Transportation agencies are building bicycle-pedestrian roundabouts on shared-use paths for the same reasons they build vehicle roundabouts on roads: improved safety and traffic flow. As with motor vehicle roundabouts, fewer conflicts occur on shared-use paths compared with traditional intersections. In the absence of definitive guidelines, it is currently up to each individual designer to relate more general criteria to the detailed design necessary for a bicycle and pedestrian roundabout. One option might be to apply standard engineering principles for traditional motor vehicle roundabouts and then adjust the designs based on the smaller size and slower speeds of bicycles. Another would be to perform tests involving pedestrians and bike users at roundabouts of different designs to help develop standards. The author suggests that it may be time to convene an effort to produce guidelines for bicycle-pedestrian-only roundabouts by bringing together the necessary expertise from roundabout designers, bicycle and pedestrian specialists, and trail and path planners. Whether on a college campus or other shared-use paths, the roundabout is an option that might minimize bicyclist and pedestrian conflicts and improve overall safety and mobility.