Yes, they only flash when the brakes are applied.
I have them set to continously flash, but they can also be set to flash for 5 seconds and then stay solid bright.
Without the barkes applied, they are on steady at a lower brightness for running lights.
I'm not sure if having them flash continuosly is legal in New York, but so far the police haven't stopped me.
The lights do seem to attract attention, because I notice many cars staying further away from me at stops.
