Is my car speedometer more accurate than my Sat nav?

Answer 1

I'm sure your speedometer is more accurate than your sat nav, the speedometer is purposely built for a sole job, to measure your speed, your navigation is meant to get you places.

Answer 2

Sat Nav is usually said to be more accurate, however in my car there is only about 1 mph difference between the two. The GPS speed is slightly lower than the speedometer speed. Speed signs at the edge of the road tend to reflect the GPS speed rather than the speedo speed. As said car speedometers can be up to 10% out. I have a Tom Tom GPS and it does have inaccuracies like reporting your position 10 meters away from where I'm actually sat if stuck at lights. I would say the GPS is likely to be more accurate, but I would use the speedo. As the speed registered on the GPS is lower it you stick to that rather than the speedo, you in reality are travelling faster. Say you were speeding and doing 80 in 70. Speedo might say 88, GPS 80 which means you are more likely to be caught, or cause an accident due to excessive speed.

Answer 3

My GPS navigation system is usually 50 to 100 off based on the turn warning it gives. If the positions is uses to compute speed are off, the speed probably is as well. The speedometer, at least in theory, is a direct measurement.

Answer 4

Most car speedometers are a few mph off anyways. Your Sat nav is your best bet.

Answer 5

Car speedometers are famous for being off, so probably no.

Answer 6

no, the gps is perfect, especially cruising at a steady speed.