31-542: State Highway 20 ( SH 20 ), also known as the Southwestern Motorway , is a New Zealand state highway linking State Highway 1 at Manukau with State Highway 16 in Point Chevalier , via Māngere and Onehunga . Along with its spurs, State Highway 20A and 20B, the state highway serves Auckland Airport , the country's largest, therefore making SH 20 a key arterial route connecting
62-855: A motorway linking the Northwestern Motorway , Dominion Road , Māngere and Wiri , also identifying the need for a rapid transport rail route along the same corridor. In 1968, the Auckland Regional Authority began planning agreements for the route between the Northwestern Motorway and Dominion Rd, while the National Roads Board (now a part of the NZ Transport Agency ) began organising the route southeast, between Dominion Road and Wiri. The first section of what would become
93-542: A series of pieces of legislation was passed to allow for the designation of main highways (starting with the Main Highways Act 1922 , followed by gazetting of roads ) and state highways (in 1936). This saw the National Roads Board, an arm of the Ministry of Works, responsible for the state highway network. From 1989 to 2008, state highways were the responsibility of Transit New Zealand , a Crown entity. In 1996
124-448: A set distance post, that post being 237 km (147 mi) from the start of the highway. In about 2004 these plaques were replaced by a new system, which gives each bridge a single number showing the distance from the start of the highway in hundreds of metres. Under the new system the bridge above would be numbered 2511, as it is 251 km (156 mi) km from the start of the highway. Motorway on- and off-ramps are numbered using
155-613: A strong impact on the Te Puea Memorial Marae community in the Māngere Bridge suburb, as the motorway cut off pedestrian access to the surrounding areas. Land reclamation as a part of the bridge construction meant the marae was no longer adjacent to the Māngere Inlet , and the land surrounding the marae was redesignated as a light industrial area. The Auckland Comprehensive Transportation Study Review (1986) confirmed
186-433: Is based on the likelihood of a single driver experiencing an accident while travelling the link in question. As of 2008, the three least safe sections of the network based on individual risk were State Highway 62 from Spring Creek to Renwick (Marlborough), State Highway 37 to Waitomo Caves and State Highway 94 from Te Anau to Milford Sound . The collective risk is based on the total number of crashes that occurred on
217-707: Is using speed reductions, wire rope barriers , wide centrelines, rumble strips , better warning signs and shoulder widening. State Highway 1 can be considered as a single highway running the length of both main islands, broken in the middle by the ferry connection at Cook Strait . It connects six of the seven largest urban areas and includes the country's busiest stretch of road. Many sections of state highway provided are marketed as tourist highways , sometimes jointly with local roading providers. Transit maintains traffic signs on and near state highways to help promote these routes. These include: Te Puea Memorial Marae Too Many Requests If you report this error to
248-591: The New Zealand Automobile Association . The system, based on similar programs overseas, categorises New Zealand state highways according to the safety of discrete 'links' (sections of the network, with a total of 10,856 km of highways separated into 172 links ranging in length from 2.4 km (1 mi) to 318 km (198 mi)). These are graded according to their 'individual risk' and their 'collective risk' based on historical crash data and traffic volumes. The individual risk
279-638: The Northwestern and Southern sections of Auckland was recognised early in the planning stages for the Auckland motorway system, and land along the Southwestern Corridor was protected against development in the 1950s. The Southwestern Motorway was a prominent aspect of a 1963 master transport plan for Auckland created by the US consultancy firm De Leuw Cather and Co, which identified a need for
310-676: The Waterview Tunnel , New Zealand's longest road tunnel, before ending at a junction with the Northwestern Motorway ( SH 16 ) SH 20, SH 20A, and SH 20B form an almost triangular shape between the Puhinui Interchange of the Southwestern Motorway, Auckland International Airport, and the SH 20/SH 20A motorway junction. The Southwestern Motorway bypasses Auckland International Airport, with spurs SH 20A from
341-536: The NLTP total) in safety, including $ 960m for policing, $ 132m for road safety promotion and $ 103m for rural SH safety. The Safe Roads Alliance is carrying out rural work on SH 1 (Waikato Expressway, Te Teko-Awakeri), SH 1B (Taupiri-Gordonton), SH 3 (Ohaupo-Te Awamutu, Waitomo-Te Kuiti), SH 11 (Airfield-Lily Pond), SH 12 (Dargaville-Tokatoka), SH 16 (Brigham Creek-Waimauku), SH 23 (Hamilton-Raglan), SH 27 (SH 26-SH 24) and SH 34 (SH 30 to Kawerau). The Alliance
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#1732780981502372-566: The NZ Transport Agency. Every five years the NZ Transport Agency will embark on a state highway review to consider whether the existing network should be expanded or reduced, according to traffic flows, changes in industry, tourism and development. From 2009 many new road schemes were classed as Roads of National Significance and, from 2020, as part of the New Zealand Upgrade Programme . Since 2013,
403-776: The NZTA has used the One Network Road Classification (ONRC) system to classify state highways and local roads. There are five categories for state highways, with an additional sixth category (Access) used only by local roads. The categories are as follows: From 2006 information, the busiest stretch of SH 1 was just south of the Auckland Central Motorway Junction , on/near the Newmarket Viaduct , with over 200,000 vehicles (either way) each day. The least busy parts of
434-666: The Southern Motorway (bypassing Wiri Station Road) was completed in 2010. A duplication of the Māngere Bridge, with future provision for rail, was also opened in 2010. The northern section was first extended to Hillsborough Road in 1989. Work began on the Mt Roskill Extension in August 2005, with construction of the section ending at Maioro Street/Sandringham Road finishing on 15 May 2009. The final section of
465-609: The Southwestern Motorway between Dominion Road and Māngere was a top priority of the Auckland Regional Authority. By 1987, the Papatoetoe Bypass was completed, linking Massey Road to the south, ending at a roundabout meeting Puhinui Road. The gap between Coronation Road and Massey Road, known as the Māngere Extension, was not completed until 1997. The Manukau Extension, connecting Puhinui Road to
496-766: The Southwestern Motorway was the Onehunga Bypass from Queenstown Road in Hillsborough to Neilson Street in Onehunga in 1977, which terminated at the Old Mangere Bridge , a low-lying concrete structure built in 1915. The contract for a new motorway bridge over the Māngere Inlet between Onehunga and Māngere Bridge was let in July 1974, with work expected to take three years to complete. In May 1978
527-656: The Southwestern Motorway, the Waterview Connection , connecting Maioro Street with SH 16 at the Great North Road Interchange commenced construction in 2012 and opened to traffic in July 2017. Additional links to the Auckland Airport were identified as necessary after the growth in air travel. SH20A, travelling from the Southwestern Motorway along George Bolt Memorial Drive, was completed in 1992. The creation of SH20B, linking
558-630: The airport to the east, began through a series of widening and extension projects on Puhinui Road, including the creation of the Pukaki Bridge in 1996. In August 2003 the Puhinui Road Interchange opened, replacing the Puhinui Road/Southwestern Motorway roundabout. Signed as exits 24A (north) and 24B (east) New Zealand state highway network The New Zealand state highway network is
589-628: The airport to the wider Auckland region and most of the upper North Island . The route also forms the southern part of the Western Ring Route , a 48 kilometres (30 mi) motorway route bypassing central Auckland. SH 20 begins from the Auckland Southern Motorway ( SH 1 ) at Manukau , then heads northwest to Māngere . It then runs over the Māngere Bridge to Onehunga, whereupon it continues northwest, cutting through Mount Roskill and Owairaka. It then enters
620-471: The construction halted when workers organised a labour strike over insufficient redundancy payments. The partially constructed bridge was picketed for a period of two and a half years, becoming the longest continuous labour strike in the history of New Zealand. Eventually, the bridge was opened in February 1983, and by 1984 the motorway extended south to Coronation Road. The construction of the motorway had
651-421: The distance in kilometres from the start of the highway. Until recently, all bridges on the network had at each end a small plaque showing the distance from the start of the highway, usually in the form of a number in kilometres, an oblique stroke, and a further number in kilometres, accurate to the nearest 10 metres. A plaque marked 237/14.12, for example, indicated that the bridge was 14.12 km (9 mi) past
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#1732780981502682-528: The funding of the network was removed from the operational functions with the creation of Transfund New Zealand, which then merged with the Land Transport Safety Authority to create Land Transport New Zealand . That was done to ensure that funding of state highways was considered on a similar basis to funding for local roads and regional council subsidised public transport. In August 2008, Transit and Land Transport NZ merged to become
713-515: The intersection with Verissimo and Landing Drives where SH 20A also terminates. From there the road continues south, along George Bolt Memorial Drive, to the airport. SH 20B leaves SH 20 at the Cavendish Dr/Puhinui Rd/Roscommon Rd Interchange of the Southwestern Motorway and travels west along Puhinui Road to the airport, officially terminating at the intersection with Orrs Road. A motorway linking
744-474: The landowners. Land within the boundaries of highway districts became subject to a rate of not more than 1/- an acre, or of 3d in the £ of its estimated sale value and that was to be equalled by a grant from the Province. By 1913 the government was collecting £21,000 in duty on cars, but spending £40,000 on roads. The idea of a national network of highways did not emerge until the early twentieth century, when
775-644: The link, which pushes safer but very highly travelled sections of the network to the top of the statistical category. As of 2008, the three least safe sections of the network based on collective risk were all on State Highway 2, on the sections from Napier to Hastings , Mount Maunganui to Paengaroa and Bay View to Napier. Both categories of assessment are to be used as an advisory tool for both drivers to inform them of dangerous road sections as well as to allow traffic controlling authorities to prioritise maintenance and safety improvements. The 2015–18 National Land Transport Programme aimed to invest $ 3.2bn (23% of
806-510: The major national highway network in New Zealand . Nearly 100 roads in the North and South Islands are state highways. All state highways are administered by the NZ Transport Agency . The highways were originally designated using a two-tier system, national (SH 1 to 8) and provincial, with national highways having a higher standard and funding priorities. Now all are state highways, and
837-708: The network (excluding off-ramps and on-ramps) are on SH 43 north-east of Whangamōmona , with fewer than 120 vehicles (counting both directions) in a day. The only remaining unsealed sections of state highway are 12 km (7.5 mi) of SH 43 and 20 km (12 mi) of SH 38 , though 38% of other roads remain unsealed. Every year the New Zealand Transport Agency produces a booklet titled AADT Data , average annualised daily traffic, that gives traffic volumes on all state highways from their automated vehicle recording system. State highways are marked with posts at irregular intervals giving
868-724: The network consists of SH 1 running the length of both islands, SH 2 to 5 and 10 to 59 in the North Island, and SH 6 to 8 and 60 to 99 in the South Island, numbered approximately north to south. State highways are marked by red shield-shaped signs with white numbering (shields for the former provincial highways were blue). Road maps usually number state highways in this fashion. Of the total state highway network, New Zealand currently has 363 km (226 mi) of motorways and expressways with grade-separated access and they carry ten percent of all New Zealand traffic. The majority of
899-486: The north and SH 20B from the east both providing airport access. SH 20A leaves the Southwestern Motorway in Māngere and travels south along an additional stretch of motorway, commonly referred to as the "Airport Motorway". The motorway passes underneath Kirkbride Road at a grade separated intersection which until 2017 was the former terminus for the motorway (and a known black spot). The motorway continues south and terminates at
930-559: The same system. In this way, travellers can accurately assess their location, and road authorities can identify each bridge uniquely. Sometimes, houses with RAPID numbering can also be used to determine the position. For example, house number 1530 is 15.3 km (10 mi) from the start of the highway. In early 2008, Transit New Zealand unveiled KiwiRAP (the New Zealand Road Assessment Programme) in cooperation with other government agencies and
961-466: The state highway network is made up of single-carriageway roads with one lane each way and at-grade access. In the early days all roads were managed by local road boards. Initially they were set up by the Provinces. For example, Auckland Province passed a Highways Act in 1862 allowing their Superintendent to define given areas of settlement as Highways Districts, each with a board of trustees elected by