I really like my 3rd light blinker, but the first day I put it on it had the opposite effect. I had just finished the install and had set it to blink as fast as possible for the minimum duration (about 5 seconds). I wanted to see how other drivers would react and took it out for a spin. The first person to get behind me was a middle-aged asian woman (it's the truth, no stereotype comments please) and she was absolutely hypnotized by the blinkenlighten. She was behind me for about five or six stoplights and at every stop she got closer to my rear bumper than anyone ever had before. Gave me the willies.

But since then, it seems to have the intended effect and I have definitely noticed cars slowing down behind me much quicker than before, especially in situations where traffic ought to be flowing but isn't because of some abnormal event like an accident up ahead.