Speed accuracy

[bwg]

Curious to know how accurate the speed indication is on the sat navs. I have Tomtom One v2 and if it is accurate then my car speedo under reads by 2mph at 30 and 4 mph at 70 which means I can go a bit faster and still be within the speed limit.

[mrralphman]

I think that a decent SatNav setup should be within 1MPH of true speed.

My car's speedo is 11% out, so when I'm doing a true 30MPH, my indicated speed is 35.
This difference gets greater the faster I go.

An Indicated 140 is only about 125 MPH

[peterc10]

If you are travelling on a reasonably straight and level road and at a constant speed the sat nav is accurate to 0.1mph. Hills make a difference (because only the horizontal distance you travelled is computed, not your actual distance) and it is a little behind with the reading of your speed.

Speedos are allowed to read up to 10% higher than real speed, but they are not allowed to read lower.
_________________
Peter
HTC Sensation
Sygic GPS for Europe (No more TT "support"!)
Copilot for USA
Bury CC9060 bluetooth car kit & Brodit mount

[Skippy]

There was a long discussion about this here

[mrralphman]

Of course...

*** Cough Cough *** 8)

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