sereiously tho... if they flash like that people might not even know you are braking... say you slam on the brakes.. minimal traction, you'll have slowed down majorly by the time the flashing has stopped, but due to it flashing it just looks to the person behind you that you are tapping the brakes and not nailing them.

ontop of that it's illegal... you WILL get a ticket if a cop ever sees you using them.