 The Nishi-ikebukuro Interchange | |
| Overview | |
|---|---|
| Location | Tokyo, Japan |
| Status | In service |
| Route |  Central Circular Route |
| Operation | |
| Work begun | 1992 |
| Opened | 22 December 2007 (initial segment) 7 March 2015 (entire tunnel) |
| Traffic | automobile |
| Character | expressway, twin-tube |
| Toll | ¥530 to ¥930 (cars) ¥1,030 to ¥1,850 (trucks) (with electronic toll collection) ¥930-¥1,850 (cash) |
| Technical | |
| Length | 18.2 km (11.3 mi) |
| No. of lanes | 2 per tube (4 total) |
| Operating speed | 60 kilometers per hour (37 mph) |
The Yamate Tunnel (山手トンネル, Yamate Tonneru) carries the Central Circular Route (C2) of the Shuto Expressway in Tokyo, Japan, from the Takamatsu on-ramp in Toshima to near the Ōi Junction in Shinagawa. It has a length of 18.2 kilometers (11.3 mi).
Lying 30 meters (98 ft) below the surface, about 70 percent of the tunnel was constructed by the tunnelling shield method. The roadway consists of two lanes in each direction. Nearly all of the tunnel lies beneath Yamate Street. On completion the Yamate Tunnel surpassed the Kan'etsu Tunnel on the Kan-Etsu Expressway, to become the longest road tunnel in Japan and the second longest road tunnel in the world. Most of the tunnel follows the route of Yamate Street (Tokyo Metropolitan Route 317).
History
Plans for an expressway on the route were first drawn up around 1970, initially in the form of an elevated expressway over the Meguro River between Shibuya and Oimachi. The elevated expressway plan was shelved shortly after, following concerns about environmental issues and local resident protests, but re-emerged in the 1990s in the form of a tunnel plan. The final plan for the southern portion of the tunnel, approved in 2004, followed Yamate Street and the Meguro River, in order to minimize tunneling under private property.
Construction on the Yamate Tunnel began in 1992. The Takamatsu–Nishi Shinjuku segment opened on 22 December 2007. On the same date, an above-ground segment linking the tunnel to the Kumanochō Interchange in Itabashi and Toshima opened. The 9.4-kilometer (5.8 mi) section between Nishi Shinjuku and Ohashi opened on 28 March 2010. The last section linking Ohashi to the Bayshore Route opened on 7 March 2015.
Facilities
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The tunnel has many operational and safety facilities. Among them are emergency telephones and cameras at 100-meter (330 ft) intervals. Fire-safety equipment includes infrared sensors, fire extinguishers, foam sprayers, and pushbutton alarms.
Emergency exits leading to a separate emergency path are located no more than 350 meters (1,150 ft) apart. Stairways lead up to Yamate Street. A duct running parallel to the roadway supplies fresh air and removes exhaust. Dust-collection systems are designed to remove 80 percent of particulates from the air.
The Ohashi Junction in Meguro, connecting the tunnel to the Shibuya Route, required construction of stacked elliptical ramps 400 meters (1,300 ft) in circumference and 175 meters (574 ft) in diameter, similar in size to the National Stadium track. For soundproofing reasons, the junction was encased in over 120,000 cubic meters (160,000 cu yd) of concrete. The structure was used as the centerpiece of an urban planning project that includes the Meguro Sky Garden park and several high-rise condominium towers.
Ramps and junctions
| Location | Exit | Name | Destinations | Notes |
|---|---|---|---|---|
| Shinagawa | C20 | Gotanda | Tokyo Metropolitan Route 317 (Yamate-dori) | Northbound entrance and southbound exit only |
| Meguro | Ohashi JCT |  Shibuya Route
|
||
| Shibuya | C22 | Tomigaya | Tokyo Metropolitan Route 317 (Yamate-dori) | Northbound entrance and southbound exit only. ETC only. |
| C23 | Hatsudai-minami | Southbound entrance and northbound exit only. ETC only. | ||
| Shinjuku | Nishi-shinjuku JCT |  Shinjuku Route
|
No access to/from Shinjuku Route east of the junction. | |
| Nakano | C24 | Nakano-chojabashi | Tokyo Metropolitan Route 317 (Yamate-dori) | Northbound entrance and southbound exit only. |
| Toshima | C25
C26 |
Nishi-ikebukuro | Tokyo Metropolitan Route 317 (Yamate-dori) | Northbound exit only. Full access southbound. |
Other underground viaducts
The Yamate Tunnel passes above the Yūrakuchō and Ōedo subway lines. It crosses below the Tōzai and Marunouchi subway lines, as well as the Keiō and Keiō New Lines and the Tōkyū Den-en-toshi Line. The tunnel runs parallel to the Ōedo Line, along a segment between Nakai and Nishi Shinjuku Gochome Stations. Nakai and Nakano Sakaue Stations, lying beneath the Yamate Tunnel, have escalators that pass between Yamate's two tunnels.
Further reading
- 西澤丞著『首都高山手トンネル』求龍堂（2007年） ISBN 978-4-7630-0725-4
References
- "Planning and Construction - Urban Long Tunnels, Yamate Tunnel". Shutoko. Metropolitan Expressway Company Limited. 17 September 2020. Retrieved 17 September 2020.
- "首都高「山手トンネル」の誕生秘話。なぜ中央環状品川線開通まで50年もかかったのか？" [The story behind the birth of the Shuto Expressway's "Yamate Tunnel". Why did it take 50 years for the Central Circular Route to open?]. bestcarweb.jp (in Japanese). 9 November 2020. Archived from the original on 22 March 2017. Retrieved 17 September 2020.
- "首都高速道路 中央環状新宿線（山手トンネル・大橋JCT） 新宿〜渋谷 山手トンネルウォーク | ラジエイト" [Shuto Expressway Central Circular Route (Yamate Tunnel / Ohashi Junction) Shinjuku-Shibuya Yamate Tunnel Walk]. radiate.jp (in Japanese). 7 March 2010. Retrieved 21 March 2017.
- "首都高に巨大天空庭園 「迷惑施設」生かす街づくり" [Huge sky garden on the Shuto Expressway. "NIMBY facility" To be used in urban planning project]. The Nikkei (in Japanese). 22 January 2013. Retrieved 21 March 2017.