Introduction to underpasses
Underpasses, where they are necessary, can overcome barriers formed by large busy highways and railways.
Separating walking and cycling by providing an underpass may be appropriate where barriers are formed by larger, higher speed roads and railways.
Where underpasses are used, they should be short, wide and direct. They must avoid deviation from pedestrian and cyclist desire lines and improve perceptions of personal safety.
Underpasses should be designed to maximise natural light and user perceptions of safety, for example by using increased headroom, keeping the approaches to the structure straight and at the same level as the natural ground and providing splayed wing walls and openings in the structure above.
The approaches to the underpass should be overlooked, providing natural surveillance, and should be well-lit. When underpasses are not sufficiently maintained, drained or lit, they can become unattractive and result in anti-social behaviour.
