Legal Question in Traffic Law in South Carolina

The way that the police and the courts have handled situations where someone was rear-ended, is that they always find the person that ran into them at fault. Reason is, the law requires that all drivers keep at a distance far enough back to allow for someone to slam on their brakes, regardless of why. After all, it is very rare that someone would do such a thing on purpose. Almost always when that happens, its because they are trying to avoid hitting something. So the law says if a person will simply keep thier car back far enough in case the person in front of them slams on their brakes, then there will never be an accident.