Car & Driver magazine analyzed "speed kills" statistics and found that the different states reporting had different standards of recording accident causes and one even lumped "too slow" in with "too fast". Also, if a driver was blind drunk and was driving too fast and both were recorded by the policeman filling out forms, the accident went in the "too fast" category. At least in the US, I believe that most accidents are caused by incompetence and lack of consequences for poor driving. For instance, here in Minnesota, once you pass the written test at 18, you never have to take it again, unless you let your license lapse for over a year. Now tell me that encourages good driving.
I believe that in Britain excessive speed is thought to be a contributing factor in 9 out of 100 accidents, and that of those 9, 3 involve the breaking of a speed limit.
Our local force (aka Gramplod) have a slogan "speed is a factor in every accident" thus explaining in a single brilliant insight why parked cars don't collide. In all fairness, they make no bones about purpose of their tax collection camera system which covers all of NE Scotland. It's called NE-SCAM.