Caldecott Tunnel Fourth Bore

Southwest County
PROJECT BUDGET $410.2 Million
CCTA & Caltrans
Between Contra Costa and Alameda counties along SR 24 north of the existing bores.

The Caldecott Tunnel fourth bore was the largest transportation project to receive federal stimulus funding in 2009.

Congestion is recurrent on Route 24 for traffic traveling between Alameda and Contra Costa counties. The existing tunnel consists of two bores constructed in 1937 and a third bore, north of the original two, built in 1964. Each of the three bores has two mixed-flow lanes, reducing the freeway capacity at the tunnels from eight to six lanes. The primary objective of the Caldecott Tunnel fourth bore is to alleviate congestion in the off-peak direction where two tunnels will be permanently dedicated to each direction.

The Caldecott Tunnel fourth bore improves mobility for motorists and ...more