Maybe they are not legal for cars but...
Not legal for cars maybe but I don't know about motorcycles because they are sold all over. That is what this application is for. Also I live in WI and have seen flashing brake lights on motorcycles in WI & IL.
They also allow for the pulsing headlights but I personally don't go for that. It looks too much like the PD.
I personally want to thank everyone for the replies. I will search out & find a resistor company on line tonight & make a purchase.