Ome Kaido

Ome Kaido is a major street running generally west from Shinjuku. Once past Shinjuku, the street becomes Yasukuni Dori.

Ome Kaido is an old highway, National Route 411, and it runs from Shinjuku to Kofu in Yamanashi Prefecture. It was a road used by travelers in the Edo period, both walking and on horseback. Parts of Ome Kaido also have other number identifiers, as it is also Tokyo Metropolitan Route 5, Yamanashi Prefectural Route 218, 205, and 6, as well as national Route 140. This makes driving along Ome Kaido extremely confusing, as the road signs will indicate what seems to be contradictory information.

In addition, what is known commonly as Ome Kaido is actually Shin Ome Kaido, or the new road. The old road is a very crooked one, and narrow, while the new one is fairly straight and wide. There are parts of the road where there is just one road, but in many places there are two roads sharing the name.

One of the most interesting features of Ome Kaido is that it is one of Tokyo's designated "Emergency Access Roads." In the case of a national emergency, such as a major earthquake in Kanto, a large part of the road will be closed to most traffic. The road is limited in such cases to emergency vehicles only, including ambulances, fire trucks, and police vehicles.

The Disaster Prevention Measures of the Tokyo Metropolitan Government mentions Ome Kaido in its English manual.
http://www.bousai.metro.tokyo.jp/english/e-knowledge/pdf/e-pamphlet_01.pdf