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Bayfarm Island Bridge (Alameda County)

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Bay Farm Island Bridge
Bay Farm Island Bike Bridge

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Bay Farm Island Bridge is located in the City of Alameda, which is located in Alameda County California. It spans the inlet to the San Leandro Bay from the San Francisco Bay. See Map

Bay Farm Island and built in 1953 by the California Public Works Department Division of Highways (Now Called, Cal Trans). The prime contractors on the project were Duncason-Harleson and Stolte Inc.  The Bridge is part of California Highway 61.

State of California, Department of Transportation owns and maintains the bridge. The bridge is regulated by the United States Coast Guard.

Bay Farm Island is a single leaf bascule draw bridge.  The old blueprints have a condition to add a second leaf if necessary.

Bay Farm Island Bridge is operational year around 7 days a week 365 days years from the Hours of 8:00 AM to 5:00 PM. If a 12 hour notice is given it can be opened after closure hours.  The bridge is manned by a alternating two person crew. The bridge is operated by the Alameda County Department of Public Works by contract with the State of California. Bay Farm is equipped with a Marine Radio, the working channel in the San Francisco Bay Area is Channel 9. The can also gain a bridge opening by using a horn. The signal is a long blast followed by a short blast.

Draw Openings:

Approximately 360 per year


The Alameda County Department of Public Works provides preventive maintenance to the bridge. Large scale repairs are done by Cal Trans.


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 Curb to Curb 26 feet
Pedestrian Sidewalk 5 Feet

Bay Farm Island Bridge is the longest draw bridge in the County at almost 1000 feet in length, however the movable span portion of the bridge is Approximately 125 feet 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 a 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's contains the machinery rooms. counterweight, and operator tower.  The bridge has three live load trunions instead of the two you normally see 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 contains four sets of brakes two main brakes and two backup brakes.  The Counterweight pit area is 50 Feet below the roadway surface. If your standing on the pit floor you’re approximately 25 feet under water.

Bay Farm Island Bridge also contains the operating console for the Bay farm Island Bike Bridge so the operator must run two bridge for each vessel opening.

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