I flash AND steady (two lights front and two back). I've written it here before. You cannot judge where a cyclist is just by the flash. Yes, the motorist knows there is a bike there, but when they get closer they cannot tell exactly where. I've used the Coast Guard experience as an example. They might see your man overboard flashing beacon, but once they get close they cannot see you very well (so they recommend a steady light in addition to the strobe).