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The N4 is a national route in South Africa that runs from Skilpadshek on the Botswana border, past Rustenburg, Pretoria, Witbank and Nelspruit, to Komatipoort on the Mozambique border. It forms the South African section of the Trans-Kalahari Corridor, which runs from Walvis Bay to Maputo, meaning that it links the east and west coasts of Southern Africa. Since the completion of the A2 through Botswana, the entire Corridor is now a world-class standard highway; it features at least one carriageway in each direction of high-speed traffic plus a paved shoulder for its entire length. The South African section can be divided into two parts with Pretoria in the middle. The western portion links Gaborone in Botswana with Pretoria, while the eastern portion links Pretoria with Nelspruit and Maputo in Mozambique. The eastern section from Pretoria to Middelburg is a four-lane dual-carriageway tolled freeway opened in 1968, with toll gates at Donkerhoek and just east of Middelburg. The freeway from Witbank to Middelburg was one of the first concrete freeways built in South Africa and the Ultra City was the first service station built on the sides of a freeway. At eMalahleni (formerly Witbank), the freeway converges with the N12 from Johannesburg. An alternative route to the N4, known as the R104, runs between Pretoria and Wonderfontein (east of Middelburg). Between Witbank and Middelburg the alternative is the dangerous R555. After Wonderfontein the toll road runs along the old alignment of the N4 until the Lebombo Border Post. From Middelburg to Belfast the N4 is a single-carriageway highway with two lanes in both directions; thereafter, the N4 is a wide shouldered single-carriageway highway. The section east of Middelburg has been significantly improved, including a northern bypass of Nelspruit, and now features some new grade-separated junctions. The N4 east of Pretoria forms part of the Maputo Corridor Toll Route. Prior to 1990, the N4 used to end at Proefplaas Interchange with the N1. However, two western sections of the N4 now exist: # Originally the N4 ran through the Pretoria CBD on regular city streets, then exited the CBD westbound on Vom Hagen Street towards Hartbeespoort Dam as the Magalies Freeway, before following the R511/R513/R512 regional routes over the Magaliesberg to meet the single-carriageway freeway built in the 1980s to a point northwest of Pretoria. All that remains of this routing of the N4 is the short 20 km tolled Magalies Freeway that runs from the Vom Hagen Street/R55 junction west of Pretoria, past Attridgeville, to Hartbeespoort where the freeway ends. It is clear from the geometry of the western terminus that the N4 was to continue, but the necessary link from the end of the freeway at Hartbeespoort to the N4 extension west of Hartbeespoort has never been completed, even though it has been planned since the 1980s. An anomaly is the bridge over Hartbeespoort Dam near Kosmos which has the R512 route number, and the two obvious deviations off the alignment at either end of the bridge where the N4 was clearly intended to continue onward. Where the N4 used to run through Pretoria, this has been renamed the M2 and M4. However, the N4 designation has not yet been removed from the Magalies Freeway itself. # At Proefplaas Interchange with the N1, the N4 now follows the N1 North as part of the Platinum Highway to just north of Zambezi Drive where it splits off westward towards Rustenburg just before the Pumulani Toll Plaza on the N1. The N4 now bypasses Pretoria through the east and the north as a four-lane dual-carriageway motorway. After Rosslyn the N4 becomes a single carriageway highway, and joins the old R27 alignment at the R512 road to Brits. Three new grade-separated junctions were built before Rustenburg, as well as a new single-carriageway bypass of Rustenburg to the south of the town. Thereafter the N4 rejoins the old alignment of the R27 just west of Rustenburg, and passes along the R27 alignment through the towns of Swartruggens and Zeerust. Just west of Zeerust, the N4 turns northwest towards the Botswana border. The toll gates can be bypassed between Rustenburg and Pretoria by following the old Rustenburg Road, now the R104. The N4 West Platinum Highway toll route (west of Pretoria) is currently operated by the Bakwena consortium under license from the South African National Roads Agency Limited (SANRAL). Bakwena is in the process of adding a second carriageway to the N4 between Brits and Rustenburg which would also widen the roadway to four lanes. However, Bakwena has not yet announced if or when it will perform a similar upgrade to the N4 between Brits and Rosslyn, which would create a continuous four-lane dual-carriageway toll freeway from Rustenburg to Pretoria. The N4 East toll route (east of Pretoria) is currently operated by Trans African Concessions (TRAC) under license from SANRAL. ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「N4 road (South Africa)」の詳細全文を読む スポンサード リンク
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