A Harley rider was killed two years ago a couple of miles from where I was living at the time: he was stopped on a two-lane road, waiting to turn left. The driver claimed not to see/notice the bike and slammed right into the back of him. To be fair, I don't know if the rider had his turn signal on ( or if he even had turn signals), but because I traveled that road every day, I took that lesson to heart and installed a "Back-Off!" brake light flasher on my bike ('06 Sprint ABS). It's small enough to fit in the wiring compartment behind the brake light and license plate, where it's easy to splice into the circuit and also be protected from the elements. I consider it a cheap ($40) preventative measure. I agree with Sport's point that a flasher might cause some confusion, but if it makes an otherwise oblivious driver notice me, I don't really care if they're a little confused! In fact, it might pull them out of their stupor faster and sharpen their awareness. I also agree with Sport's comment about turn signal color: they should all be amber to avoid confusion; why aren't they? +1 re: Dusty's idea of frequency increasing with severity. My daily commute includes some dense traffic so when driving, I frequently tap my brakes to signal to those behind me that I'm slowing down: once or twice if slowing, three or more if I'm coming to a (quick) stop. I'm convinced that it's prevented me from being rear-ended many times! OK, I'm done. :asb: