State Highway 1 (SH 1) is the longest and most significant road in the New Zealand road network, running the length of both main islands. It appears on road maps as SH 1 and on road signs as a white number 1 on a red shield, but it has the official designations SH 1N in the North Island, SH 1S in the South Island. SH 1 is long, in the North Island and in the South Island. Since 2010 new roads have reduced the length from . For the majority of its length it is a two-lane single carriageway, with at-grade intersections and property accesses, in both rural and urban areas. These sections have some passing lanes. Around of SH 1 is of motorway or expressway standard : in the North Island and in the South Island. Route North Island (SH 1N) SH 1 starts at Cape Reinga, at the northwestern tip of the Aupouri Peninsula, and since April 2010 has been sealed (mainly with either chipseal or asphalt) for its entire length. From Waitiki Landing south of Cape Reinga, SH 1 travels down the central-eastern side of the peninsula to Kaitaia, New Zealand's northernmost town, then travels through a new piece of road in the Mangamuka Gorge before turning south-east across the Northland Peninsula on to Kawakawa in the Bay of Islands where the roadway is shared by the Bay of Islands Vintage Railway track, and then south to the city of Whangārei, the largest urban area in Northland. SH 1 then skirts the south-western Whangārei Harbour, nearing the coast briefly at Ruakākā, before proceeding down to wind through the Brynderwyn Hills before approaching the upper reaches of the Kaipara Harbour. The highway crosses into the Auckland Region, and passes through Wellsford and Warkworth, again heading for the east coast. Near Puhoi, on the Hibiscus Coast, SH 1 widens to a four-lane motorway known as the Auckland Northern Motorway. The first of the motorway is an automated toll road. At Orewa, the motorway becomes toll-free, crossing farmland to the North Shore of Auckland. The road crosses through suburbs to the Waitematā Harbour, which it briefly follows before crossing it by the Auckland Harbour Bridge. The motorway comes off the bridge into Auckland's city centre, and forms its western boundary as SH 1 proceeds to the Central Motorway Junction. At this junction, SH 1 becomes the Auckland Southern Motorway, and,