> In Britain at least we call it "braking distance" and you're supposed to leave 2 seconds at least between you and the person in front. Count it off a lamp post/sign etc.

Indeed, that is the usual definition in the US for following distance. Along with a typical example of how to determine it for yourself.

We usually use the term braking distance to describe the distance that would be required to stop the car based on current conditions and speed. This is not necessarily going to be the same as the following distance.