I've often wondered about the legality of having blue flashing lights on your person while riding a bike. Technically the vehicle (bike) doesn't have blue lights, but the rider does. Only reason I've wondered is because I took one of those small white LED lights you strap onto your handlebar and replaced the white light with a bright multicolored LED. If it were mounted on the back of my helmet it would get attention as it flashes red, green, and blue. But if a cop would have a problem with it then I won't do it.