The draw of the California Department of Transportation highway bridge, mile 11.2 at the head of Grand Island, shall open on signal from May 1 through October 31 from 6 a.m. to 10 p.m. At all other times, the draw shall open on signal if at least four hours notice is given to the drawtender at the Rio Vista bridge across the Sacramento River, mile 12.8.
33 C.F.R. §117.199