Bay Farm Island Bridge

The Bay Farm Island Bridge is a 125 foot single leaf bascule bridge. It spans the San Leandro Bay inlet to the Oakland Estuary at Otis Drive, and is similar to the Fruitvale Avenue Bridge. The Oakland Estuary is a navigable water way with access to the San Francisco Bay. 

A bascule bridge is a a draw bridge that is counter-weighted so that it may be raised or lowered easily. The bridge, owned by the State, was built by contractors Duncason-Harleson Company and Stolte Inc in 1952. It is operated by the Alameda County Public Works Agency by contract with the State of California. The Public Works Agency provides preventive maintenance to the bridge, but large scale repairs are done by the California Department of Transportation, District 4.


The original bridge was completed in 1854 and was built of wood with an oyster shell surface, similar to the approach roads. It was originally a toll bridge, but the owners stopped collecting the toll and abandoned the bridge when a land speculation deal on Bay Farm Island went bad. It eventually rotted and was replaced by a bridge built by the County, which was then replaced by a swing span bridge built in 1881 with the remains of a failed Webster Street bridge.

The current Bay Farm Island Bridge was built by the California Public Works Department Division of Highways (CalTrans). The prime contractors on the project were Duncason-Harleson and Stolte Inc. The Bridge is part of California Highway 61. The State of California, Department of Transportation owns and maintains the bridge.

Adjacent to the Bay Farm Island Bridge is a bicycle/pedestrian drawbridge operated by Alameda County. Its 10.75 foot roadway carries bicycles, pedestrians and provides access for the handicapped. It connects the bike paths on Bay Farm Island to the Fernside Boulevard shoreline path.


Bay Farm Island Bridge shall open on signal; except that, from 5 a.m. to 8 a.m. and 5 p.m. to 9 p.m., the draw shall open on signal if at least 12 hours notice is given. Notice shall be given to the bridgetender of the Bay Farm Island bridge from 8 a.m. to 5 p.m. and to the bridgetender of the Park Street Bridge at Alameda at all other times. The draw need not be opened for the passage of vessels from 9 p.m. to 5 a.m.

The bridge is manned by a alternating two person crew. The bridge is equipped with a Marine Radio, the preferred working channel in the San Francisco Bay Area is Channel 9 and Channel 16 is used for hailing and distress. Vessels can also gain a bridge opening by using a horn. The signal is a long blast followed by a short blast. Signal flags and lights may also be used if Coast Guard approved methods are followed. For more information on drawbridge operations, see "California Drawbridge Regulations" by the Coast Guard.

There are approximately 360 draw openings a year. Although draw bridges are required to open for vessel traffic even if that means that vehicular traffic must wait, there are some exceptions to this rule.


Bay Farm Island Bridge is the longest draw bridge in the County. It is almost 1000 feet in length, however the movable span portion of the bridge is approximately 125 feet in length, giving a channel clearance of just 92 feet 4 inches.

Over 40,000 vehicles cross Bay Farm Island Bridge every day. To stop all these vehicles and pedestrians requires the use of 4 traffic gates, one vehicle barrier, and 2 pedestrian gates. The bridge operator also must stay in contact with the City of Alameda Fire and Police Dispatcher in case any vehicle is in route to an emergency or hospital. The bridge will not open in this instance.

The bridge has some unique characteristics. Instead of having the machinery room and operator tower close to or on the shore like the other bridges its has a huge concrete cofferdam in the channel that contains the machinery rooms, counterweight, and operator tower. The Counterweight Pit Area is 50 feet below the roadway surface. If you are standing on the pit floor you’re approximately 25 feet under water.

The bridge has three live load trunion pedestals instead of the two normally on a bascule type bridge. It also has dual machinery rooms that work in tandem. The bridge is powered by two 50 HP electric motors. The bridge operates with four sets of brakes, two machinery brakes and two motor brakes.

Adjacent to the Bay Farm Island Bridge is a bicycle/pedestrian drawbridge operated by Alameda County. Its 10.75 foot roadway carries bicycles, pedestrians and vehicles for the handicapped. Bay Farm Island Bridge also contains the operating console for the Bicycle Bridge so the operator must control two bridges for each vessel opening.


  • Vertical Clearance MLLW (Low Tide) 26'
  • Vertical Clearance MHHW (High Tide) 20'
  • Clearance Between Fenders 92 Feet 4 Inches
  • Maximum Load Limit 150,000 to 160,000 Pounds
  • Bridge Width 70 Feet 6 inches
  • Bridge Length 963 Feet 6 Inches
  • Roadway Width 26 feet
  • Pedestrian Sidewalk 5 Fee