The Sydney Harbour Bridge is a steel through arch bridge in Sydney, spanning Sydney Harbour from the central business district (CBD) to the North Shore. The view of the bridge, the harbour, and the nearby Sydney Opera House is widely regarded as an iconic image of Sydney, and of Australia itself. Nicknamed "The Coathanger" because of its arch-based design, the bridge carries rail, vehicular, bicycle and pedestrian traffic. Under the direction of John Bradfield of the New South Wales Department of Public Works, the bridge was designed and built by British firm Dorman Long of Middlesbrough, and opened in 1932. The bridge's general design, which Bradfield tasked the NSW Department of Public Works with producing, was a rough copy of the Hell Gate Bridge in New York City. This general design document, however, did not form any part of the request for tender, which remained sufficiently broad as to allow cantilever (Bradfield's original preference) and even suspension bridge proposals. The design chosen from the tender responses was original work created by Dorman Long, who leveraged some of the design from its own Tyne Bridge which, though superficially similar, does not share the graceful flares at the ends of each arch which make the harbour bridge so distinctive. It is the eighth longest spanning-arch bridge in the world and the tallest steel arch bridge, measuring from top to water level. It was also the world's widest long-span bridge, at wide, until construction of the new Port Mann Bridge in Vancouver was completed in 2012. Structure The southern end of the bridge is located at Dawes Point in The Rocks area, and the northern end at Milsons Point on the lower North Shore. There are six original lanes of road traffic through the main roadway, plus an additional two lanes of road traffic on its eastern side, using lanes that were formerly tram tracks. Adjacent to the road traffic, a path for pedestrian use runs along the eastern side of the bridge, whilst a dedicated path for bicycle use runs along the western side; between the main roadway and the western bicycle path lies the North Shore railway line. The main roadway across the bridge is known as the Bradfield Highway and is about long, making it one of the shortest highways in Australia. Arch The arch is composed of two 28-panel arch trusses; their heights vary from at the centre of