Interesting. Here we use the same type of set-up, but with 12-12-12 signals facing the firehouse (default flashing red) and 12-12-8 signals facing the road (default flashing 8" yellow instead of 12" green). When the button is pressed, the 12" yellow comes on then the 12" red like a normal signal and the firehouse signal goes green. Half the time the signals aren't even used. The same signal set-up is used for crosswalks and railroad crossings here.

I have seen 12R-12Y-8FY, on the street, and 8-8-8 facing the firehouse here, in Pasadena and Montclair.