Join Date: Feb 2007
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Just because you don't get caught speeding doesn't mean either your speedo or GPS system is accurate. That's a bit like saying I have smoked all my life but I haven't got cancer Yet!
During manufacture the speedo manufacturers have a tolerance of plus or minus 10% - but many are much more accurate than this. But to keep themselves within the law and stop being sued they will always tend to under-read. A speedo gives an instant real time display whereas a GPS system needs time over which to calculate distance. The downside of the GPS system is that it only measures over straight line distances - so if you were travelling along winding and/or undulating roads the distance measured and the actual distance travelled could be out by quite a bit. Additionally GPS satellites need to have there clocks updated at least once every 12 hours or so (this is done by the US military). Guess which satellites get ignored when they are busy - it definitely ain't the military ones that's for sure. In the interests of safety and my licience I'm sticking with my speedo reading
Currently in madnoel10's garage:
Honda Civic 1.4l