by the NorthLink WA project that upgraded and extended the Tonkin Highway to Muchea. This section remains in use for local traffic and tourism to the Swan Valley area. Route description Great Northern Highway is the main north-south route between Perth and the northern areas of Western Australia. Covering a distance of , it is the longest highway in Australia. From Midland in Perth's north-east, the highway heads generally north-east through the Wheatbelt and Mid West to Newman, north-west to the coastal Pilbara town of Port Hedland, along the coastline to Broome, east to Halls Creek, and finally north to Wyndham, on the state's northern coastline. out from Wyndham, the highway intersects the start of Victoria Highway, which carries interstate traffic to the Northern Territory via Kununurra. Various road routes are allocated to sections of Great Northern Highway, which is mostly a National Highway route, and also forms part of Australia's Highway 1. It is signed as National Route 1 from Midland to Middle Swan, National Highway 95 and National Route 1 concurrently from Middle Swan to Muchea, National Highway 95 from Muchea to Mundabullangana, and National Highway 1 from Mundabullangana to Victoria Highway. The vast majority of the highway is a two-lane single carriageway, although there are thirteen single-lane bridges and four single-lane floodways in the Kimberley. The speed limit is except in and around built up areas. Great Northern Highway travels to remote areas of Western Australia, including the Munjina Roadhouse near the Hamersley Ranges, and the communities of Eighty Mile Beach, Wallal, Sandfire and Mandora, which are located between Broome and Port Hedland. It is the only sealed road between the Northern Territory border and major population centres in the north of the state. Economically, Great Northern Highway is also a vital link in the resource rich regions of the Wheatbelt, Mid West, Pilbara, and Kimberley. The key industries of mining, agriculture, and pastoral stations are all dependent on the highway as a significant and in some cases only method of transport. Tourism accounts for a significant portion of the road's traffic, and is a growing part of or potential growth source for the regional economies. The highway provides access to a variety of tourist attractions, including New Norcia and various national parks, including Karijini. Parts of the highway itself are included in the tourist routes Swan Valley Tourist Drive (Tourist Drive 203) in Perth, Chittering Valley