The draw of the S70 bridge, mile 23.8 (Landside Route) near Belle River, shall open on signal; except that, from 10 p.m. to 6 a.m., the draw shall open on signal if at least four hours notice is given. During the advance notice period, the draw shall open on less than four hours notice for an emergency and shall open on demand should a temporary surge in waterway traffic occur. [CGD 08-84-07, 50 FR 24195, June 10, 1985]