我想知行人天橋的作用~~~~thx

Pedestrian over-crossing is necessary when surface vehicular traffic is heavy. By grade separating(elevating) the pedestrians and separating them from the vehicular traffic, there will be less vehicle/pedestrian conflicts, minimizing the possibility of accidents, and for signalized intersection, more green time could be granted to the vehicular traffic and cut down the delay of traffic.

Pedestrian overcrossing
- to separate pedestrians from surface road traffic.
- provide a safe walkway for pedestrian, esp. in central business district.