The two formulas, time vs. distance will yield about the same distance.  But
it is much easier for a driver to note when the vehicle ahead passes a point
on the road and count seconds till the following car gets to the same
point.  The two to three second rule assumes the same stopping distance for
both vehicles, it takes into account the reaction time of the following
driver.  Just easier to teach new drivers (and remind experienced drivers)
how to tell when they are following to close, especially at highway speeds.
And driving a loaded Westy, add a little more time, you don't want to be
making high speed maneuvers to take a different lane or the shoulder.

On 10/16/06, Jake de Villiers <crescentbeachguitar@gmail.com> wrote:
>
> Loren, I'm pretty sure that the formula of 1 car length for every 10 miles
> an hour is all about variations in speed.
>
>
>