after sweeping around the southern end of central Auckland, proceeds in a south-easterly direction. The motorway continues in a broadly southeast direction across the Auckland isthmus, then through Manukau and Papakura to the top of the Bombay Hills, just short of the Auckland/Waikato boundary. At Bombay, SH 1 becomes the Waikato Expressway, a four-lane dual-carriageway expressway. The expressway takes the highway down the Bombay Hills to Mercer, where SH 1 meets the Waikato River, which it broadly follows for the next . The Waikato Expressway bypasses Hamilton city centre to the east, then bypasses Cambridge to the north before reverting to a single carriageway east of the town. The highway continues eastward to the town of Tīrau, where it turns south to pass through Putāruru and Tokoroa and the surrounding exotic pine plantation forest area. At Wairakei, SH 1 takes an eastern route to bypass Taupō and meet the Lake Taupō shoreline south of the town near the airport. SH 1 follows the eastern shore of the lake for to Tūrangi, at the southern end of the lake. Via SH32/41 the distance is about shorter than this section of SH1. Turning southwards again, SH 1 leaves Tūrangi and ascends onto the North Island Volcanic Plateau, passing through the fringes of the Tongariro National Park and into the Rangipo Desert, passing the volcanoes of Ruapehu, Ngauruhoe and Tongariro. The road between Rangipo ( south of Tūrangi) and Waiouru is commonly known as the Desert Road. SH 1 enters the Manawatū-Whanganui Region, and descends through an army training area to the end of the Desert Road at Waiouru. From Waiouru, the highway follows tributaries of the Rangitikei River through Taihape to meet the main river at Utiku. It then follows the western bank of the Rangitikei through Ohingaiti and Hunterville to Bulls. At Bulls, SH 1 turns southeast to cross the river, turning southwest again down the road at Sanson. SH 1 crosses the Manawatu Plain, passing the city of Palmerston North about west of it. It passes through Foxton, before reaching the end of the plain at Levin. From Levin, SH 1 follows the narrowing western coastal plain southwards. The highway crosses into the Wellington Region south of Levin, and just north of Ōtaki widens into the Kapiti Expressway, a fully grade-separated four-lane dual carriageway. This expressway bypasses the Kāpiti conurbation of Waikanae, Paraparaumu and Raumati, before reaching the end of