Last Sunday I climbed up Mount Diablo. It was a beautiful climb, and bit by bit we reached the summit. On the way back down, going down the winding road, I nearly hit a car - it was an awful experience. Here is the YouTube video:
It doesn't look much. But the car came up SO fast. I thought I was going to go under the car. What was a beautiful day, turned into a nightmare! Dave Fisch and I discussed it. He thought Rob Crowe makes excellent points: http://cyclingtips.com.au/2010/04/descending-tips/
One thing: we cannot do this on the ride across America!