(a) This section applies only to a traffic-actuated electric traffic-control signal that consists of a traffic-control signal for which the intervals vary according to the demands of vehicular traffic as registered by a detector and that is installed and operating at an intersection.
(b) In addition to any other type of vehicle the presence of which the detector for the traffic-actuated electric traffic-control signal may register, the detector for a traffic-actuated electric traffic-control device to which this section applies must be capable of registering the presence of a motorcycle or moped.