(a) General rule.--Cities may locate, build and maintain bridges, wholly or partially within the city limits, along with the piers, abutments and approaches appurtenant to the bridges, to be used as public streets. (b) Definition.--As used in this chapter, the term 'bridge' shall mean a structure built to span and provide passage over a valley, road, railroad track, private property, river, creek, stream or any other body of water or physical obstacle and shall include viaducts constructed from a series of spans or arches.
Pennsylvania Legal Code