Dumbarton Bridge | What Is MTC? | About MTC

Dumbarton Bridge

Dumbarton Bridge
Dumbarton Bridge

The original Dumbarton Bridge was the first vehicular crossing over San Francisco Bay proper. It was rebuilt in 1984 for safety and traffic congestion reasons. The Dumbarton now provides three lanes in each direction, separated by a concrete barrier, as well as a bicycle/pedestrian path.

The western approach to the Dumbarton Bridge from U.S. 101 — the Bayfront Expressway — was widened from four lanes to six lanes as part of BATA's RM 1 program. Widening of the expressway was completed two months ahead of schedule in July 2003.

Caltrans and BATA evaluated the seismic safety of the bridge and determined it requires seismic retrofit work to make the bridge safe during a major earthquake. A seismic retrofit project was completed in January, 2013.

Bridge Facts At-A-Glance
LOCATION: State Route 84 between San Mateo and Alameda counties near Newark and East Palo Alto
STRUCTURE: Steel box girder and pre-stressed concrete approach spans
LENGTH: Total length 1.6 miles
CHANNEL SPAN: 340 feet


  • Original Structure: January 1927 (replaced)
  • New Structure: October 1982
  • 1927 structure: $2.25 million
  • 1982 structure: $70 million
COLLECTION: One-way, westbound in Newark
TRAFFIC LANES: Three in each direction
FY 2018-19 TOTAL TOLL-PAID VEHICLES: 12,004,287
FY 2018-19 TOTAL TOLLS COLLECTED: $62,402,620
BRIDGE PATH COUNTER DATA: Access bicycle and pedestrian counter data