__Stopping distances__

As a bit of a side note, I just want to remind all of you of how
the stopping distance is related to v^2 , so don't get fooled
into thinking that if you go twice as fast it'll just take twice
the distance to stop. That's wrong. If you're going fast enough,
that estimation will be off by quite a bit. The same goes for
the 2 second rule for traveling behind cars. If you're going fast
enough, the rule isn't that effective. Not to mention, at higher
speeds, the friction from your tires decreases.

#### Fig.3 Stopping and minimum following distances as recomended
by the two-second rule. (from __The Physics Teacher__)