I just don't get it. A bike is, at most, 6 feet long. (Excluding tandems and bents.) If you are sitting a few feet behind a car, then your back end is at most, 10 feet from the back of the car in front of you. (Often less, I'll literally sit a foot away from the car most of the time.) A car coming behind you cannot be traveling that fast in those 10 feet if they plan to stop without hitting the car.
If they DO hit the car, you're probably going to get hit even if you ARE beside the car instead of behind it. I prefer to remain as visible as possible at stoplights/stopsigns, in the middle of the lane.
A car traveling at 10 mph will cover the 10 foot gap in less than a second. A car traveling 5 mph will cover that 10 foot gap in slightly over a second. Unless a car is FLYING and SLAMS on their brakes, they PROBABLY won't encroach on that 10 foot buffer at any significant speed. And if they DO hit and break your bike, you get a new one.
