I'm on a three-mile hill that is very popular with bicyclists. They struggle up the hill, then coast down silently like a bat outa hell. I have a really hard time seeing them when I'm walking across the road to get the mail, and I can't imagine they can stop. I've had a few close calls. I'm glad bicycles are starting to have running lights or strobes. The cars are hard to see, too - but they're much more likely to have running lights (and brakes).
-Joe-