What bay does the San Mateo Bridge cross?

The San Mateo–Hayward Bridge (commonly called the San Mateo Bridge) is a bridge crossing the U.S. state of California's San Francisco Bay, linking the San Francisco Peninsula with the East Bay. The bridge's western end is in Foster City, a suburb on the eastern edge of San Mateo. The eastern end of the bridge is in Hayward. It is the longest bridge in California and the 25th longest in the world by length. The bridge is owned by the state of California, and is maintained by Caltrans, the state highway agency.

The bridge was considered the worst evening commute in the Bay Area, which ended with the completion of a new eastern trestle carrying westbound bridge traffic in 2002. Eastbound bridge traffic took over the old trestle completely, although eastbound traffic was not expanded to three lanes until February 2003. Funded as part of BATA's regional Measure (RM) 1 program, which raised bridge tolls, the new low-rise trestle portion of the bridge added 10 feet (3.0 m) shoulders on both sides in both directions and effectively widened traffic from four to six lanes, matching the configuration of the high-rise portion of the bridge. With the completion of the new westbound trestle, the speed limit on the bridge was raised to 65 miles per hour (105 km/h).

Tolls are only collected from westbound traffic at the toll plaza on the east side of the bridge. Since July 2010, the toll rate for passenger cars is $5.