The draws of the Ferry Street bridge, mile 2.6, and Canadian National Railway bridge, mile 3.8, both at Buffalo, shall operate as follows:

(a) From April 15 through November 30, the draws shall open on signal. However, between the hours of 12 midnight and 8 a.m., seven days a week, no bridgetender is required to be in attendance at the bridges and the draws shall open on signal if notice is given to the owners at least two hours in advance of a vessel's intended time of passage through the draws.

(b) From December 1 through April 14, no bridgetender is required to be in attendance at the bridges and the draws shall open on signal if notice is given to the owners at least four hours in advance of a vessel's time of intended passage through the draws.