To continue the caravan analogy (before it starts to get a bit silly) your aim is to come to a complete stop, so you must keep breaking. Inappropriately hard breaking would be like having a confrontational Hitchenesque debate with your elderly aunt at a family Christening. Not breaking enough would be like . . . er . . . I think that's enough of this analogy.
Regards
Grimesy
Regards
Grimesy