The original Dumbarton Bridge, first vehicular crossing of San Francisco Bay, was opened to traffic on January 15, 1927. It linked southern Alameda County on the east to San Mateo County on the west.

Built originally to provide a shortcut for traffic originating in San Mateo and Santa Clara Counties, the bridge served industrial and residential areas on both sides. The bridge was built with private capital and then purchased by the State for $2.5 million in 1951.

Its age and the limitations of a two-lane undivided roadway and lift-span made it necessary for a replacement bridge to be constructed 90 feet to the north. This bridge, a six-lane, high-level structure, was opened to traffic in October 1982. The cost of the complete project was $200 million.

It is 8,600 feet long with a shoulder in each direction for emergency use and a two-way bicycle and pedestrian path on the eastbound side. A 340-foot center span provides 85 feet of vertical clearance for shipping. The approach spans on both sides of the Bay are of prestressed lightweight concrete girders supporting a lightweight concrete deck. The center spans are twin steel trapezoidal girders which also support a lightweight concrete deck.

The bridge carries over 61,000 vehicles daily. Toll for a 2-axle vehicle is $3, collected from westbound traffic.