School Zone Santa .Com

This morning to get an idea of numbers I decided to let nature take it's course and count the number of flashes of the south bound camera during school zone time.
One flash in 1 1/2 hrs when an ambulance drove south at speed ,with lights flashing and siren going approx 8.30 am
There were numerous cars that went past exceeding 40klm and no flash.
Don't these cameras need a flash anymore or hadn't the timer switched over from the 60klm mode ?
Is it faulty?