Section 3906 - Signal Systems(a) Signal systems which will warn operators against dispatching other passenger-carrying units in the event a previously dispatched unit has failed to clear an automatic stop shall be provided on all amusement rides where the lack of such a system may permit rear-end collision and injury to passengers.(b) Signal systems for the starting and stopping of amusement rides shall be provided where the operator of the ride does not have a clear view of the point at which passengers are loaded or unloaded.(c) Where the need for coded signals is indicated, any code of signals adopted for the operation of any amusement ride shall be printed and be kept posted at both the operator's and signalman's stations. Signals shall be thoroughly understood by all persons who use them.(d) Signals for the movement of rides shall not be given until all passengers are safely within the conveyance and all persons are in the clear.(e) Types of signal systems shall be tested at least once each day of operation and prior to the operation of the ride. Rides shall not be operated if the signal system is not functioning correctly.Cal. Code Regs. Tit. 8, § 3906