Caldecott Tunnel
From Free net encyclopedia
The Caldecott Tunnel is a three bore tunnel in Oakland, California. The east-west tunnel is signed as a part of California State Highway 24, and connects Oakland to communities in Contra Costa County, through the Diablo Range. The tunnel is named after Thomas F. Caldecott, president of Joint Highway District 13, which built the first two tunnels.
Bore 1 (the southernmost bore) and Bore 2 were completed in 1937 and are each 3,610 feet (1,100 m) long and carry two lanes of traffic. Bore 3 (the northernmost bore), built in 1964, is 3,771 feet (1,149 m) in length, and also carries two traffic lanes.
The middle bore (Bore 2) can be shifted to accommodate heavy traffic. Generally, it carries westbound traffic from about midnight to noon and eastbound traffic from about noon to midnight.
History
In the 19th century, traffic over the Berkeley Hills in this area went up Harwood Canyon, now known as Claremont Canyon. In 1903, a tunnel was built above the present location of the Caldecott Tunnel, approached by a new road dubbed "Tunnel Road" which started at the top of Ashby Avenue in Berkeley.
In 1929, construction of the first two bores of the Caldecott Tunnel began. They were completed in 1937, and were originally known as the Broadway Low Level Tunnel as the approach was from the top of Broadway in Oakland. However, access from Ashby Avenue was retained as it was designated the connecting thoroughfare from the Eastshore Highway (now Freeway) and the San Francisco-Oakland Bay Bridge, and dubbed State Highway 24. The third bore was opened in 1964. In the late 1960s, the Grove-Shafter Freeway was completed and replaced Broadway as the main access route to the Caldecott Tunnel. Ashby Avenue was redesignated State Highway 13 and aligned with the new Warren Freeway through the Montclair District of Oakland. The Grove-Shafter Freeway was then designated State Highway 24.
In 1982, a major fire was set off in the north bore, one of the few to have involved a gasoline truck. In 2000, the California Department of Transportation began planning the possibility of a fourth bore, due to increased traffic along the route.