It should be noted, however, that where walkways are designed to accommodate bicycle travel, the resulting geometrics required for bicycles will likely meet or exceed the geometric needs for pedestrians. Such bollards should not be placed to obstruct or otherwise interfere with the path of travel of bicyclists or pedestrians proceeding in either direction. Where possible, decking should be laid 90 degrees to the direction of travel. Overpasses and Underpasses A pedestrian overpass or underpass is a type of bridge facility. May require long approach ramps to meet ADA requirements and achieve clearance over most roadways.
Additional clearance is required over railroad tracks and waterways.
Can block views and be unsightly. May not be used by pedestrians if they have to climb long ramps and or stairs Ramps can invite skateboarders. Where topography permits or where roadways are elevated, an undercrossing may be constructed with little or no change in grade. Often, they are less expensive to build than overpasses. Can be expensive.