David, if the sign is on all the time.
If you could be awake at 3-4 am, and drive past at a speedo indicated
60mph, and see what the sign tells you. :)
It would be better at 100mph, but I don't think the van can get that fast. :D

Sudhir

On 9/3/07, David Kao <dtkao0205@yahoo.com> wrote:
> --- Kim Brennan <kimbrennan@MAC.COM> wrote:
> >
> > My calculations of margin of error are based on GPS values for speed
> > and distance.
> >
>
> I have zero knowledge about GPS values for speed and distance. Does GPS
> give more accurate measure of speed and distance? I understand GPS is extremely
> accurate and reliable to pin point your location and maybe the distance
> between locations. But how does it measure the actual traveling distances
> between two points? Does it track every foot of your track and add up to
> get the total distance you have traveled? Or does it use its software
> to add up straight distances of some not too short segments along the route
> you have traveled? If the latter is the case then I have to doubt its accuracy.
>
> My house is located near by a school. There is a radar speed detector with
> large digital display on the street. I often used it to check my speedometer.
> I have found my speedometers of all my cars just about dead on accurate.
>
>
>
>
>
>
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