While most bridges and underpasses primarily serve motor vehicle traffic, they may also represent the only nearby option for pedestrians to cross a significant barrier. To serve the needs of pedestrians, grade‐ separated crossings should consider accessibility, user comfort, and personal safety, including preserving good sight lines.

Pedestrian facilities should be provided on both sides of vehicular bridges and underpasses in all area types. See below for design parameters specific to bridges and to underpasses. Bridges and underpasses with PAR should consider lighting for personal comfort and safety for users. Further guidance about lighting is available in .

A PAR should be provided as part of on-system bridges on both sides of vehicular bridges in urbanized areas, if only as an emergency exit path for stranded motorists or pedestrians who have no alternative route. In urban and suburban areas, this walking area should consist of a sidewalk and/or shared use path.

Wherever possible, sidewalk widths across bridges should be the same or greater than the clear width of the existing connecting sidewalks. A greater width provides increased pedestrian comfort by allowing people to walk further away from moving traffic. Where shared use paths are used over bridges, the clear width of the shared use path must be wider than the connecting sidewalk to account for the recommended 2-ft shy (1-ft min.) distances from adjacent railings and barriers.

Pedestrian facilities such as sidewalks must be provided at vehicular underpasses. Where underpasses are constructed without pedestrian facilities, designs should anticipate and provide space for pedestrian facilities to be constructed in the future.

Wherever possible, sidewalk widths through underpasses should be the same as the clear width of the existing connecting sidewalks. See for vertical clearance requirements for pedestrian crossover structures.

Underpasses that are below grade should provide clear sight distances to and through the underpass. Drainage must be carefully considered to maintain accessible use of underpasses. Overhead clearance for pedestrians is much less than clearance for vehicles, so it is possible to lessen the grade for sidewalks at below grade underpasses. This will make the sidewalk more useable and can increase safety as well.

Lighting should be considered for pedestrian facilities within underpasses. This lighting can be placed along the sidewalk buffer zone or attached to the overpass structure.