No bridge erected or maintained under the provisions of sections 491 to 498 of this title, shall at any time unreasonably obstruct the free navigation of the waters over which it is constructed. if the bridge shall be constructed with a draw, then the draw shall be opened promptly by the persons owning or operating such bridge upon reasonable signal for the passage of boats and other water craft.
United States Code Title 33 section 494
In the event that a draw bridge is unable to operate for any reason, the bridge is to remain open to vessel traffic until the bridge is again operational or is removed.
Owners of draw bridges shall ensure that the necessary draw tenders are provided for the safe and prompt opening of the draw. They shall ensure that all operating machinery of the draw is maintained in a serviceable condition and that the draws are operated at sufficient intervals to assure their satisfactory operation.
Enforcement of these regulations is the responsibility of the United States Coast Guard reporting to the United States Department of Transportation.
§117.181 Oakland Inner Harbor Tidal Canal
Code of Federal Regulations Title 33
Subpart B - Specific Requirements
The draws of the Alameda County highway bridges at Park Street, mile 5.2; Fruitvale Avenue, mile 5.6; and High Street, mile 6.0; and the U.S. Army Corps of Engineers railroad bridge, mile 5.6 at Fruitvale Avenue, shall open on signal; except that, from 8:00 a.m. to 9:00 a.m. and 4:30 p.m. to 6:30 p.m. Monday through Friday except Federal Holidays, the draws need not be opened for the passage of vessels. However, the draws shall be open during the above closed periods for vessels which must, for reasons of safety, move onto a tide or slack water, if at least two hours notice is given. The draws shall open as soon as possible for vessels in distress and emergency vessels, including commercial vessels engaged in rescue or emergency salvage operations.
§117.193 San Leandro Bay
The draws of the California Department of Transportation highway bridge, mile 0.0 (kilometer 0.0) and the City of Alameda bicycle bridge, mile 0.1 (kilometer 0.2) between Alameda and Bay Farm Island, shall open on signal; except that, from 5:00 a.m. to 8:00 a.m. and 5:00 p.m. to 9:00 p.m., the draw shall open on signal if at least 12 hours notice is given. Notice shall be given to the drawtender of the Bay Farm Island bridge from 8:00 a.m. to 5:00 p.m. and to the draw tender of the Park Street Bridge at Alameda at all other times. The draws need not be open for the passage of vessels from 9:00 p.m. to 5:00 a.m.