> I was stationary in a traffic jam when I was rear-ended by the car in back of me. Fortunately, I was not hurt at all. I believe yholio's statement about "whe

> I was stationary in a traffic jam when I was rear-ended by the car in back of me. Fortunately, I was not hurt at all. I believe yholio's statement about "when correctly used" was meant to be "when correctly used by all participants"; i.e., no single participant can guarantee their own, or anyone else's, safety, no matter how careful they are. On the other hand, the guarantee is, as yholio notes, of an almost entirely theoretical nature even given universal cooperation: > The safety guarantees work only when humans demonstrate almost super-human regard to the safety of others, are never inattentive, tired, in a hurry or influenced by substances or medical conditions etc.