Failed driving test as sat nav speed incorrect.

samba987

Hi, So I failed my 1st driving test yesterday, only because of 1 serious fault (speed).

Just before a national speed limit it was 30mph zone. When I was about 150 yards from the change of speed I checked my mirrors, as I did so the car went to 31mph as it went slightly downhill at that time.


The examiner without looking at the speedometer (can only see 70MPH+ from the passenger seat) told me I was speeding. When I looked at the sat nav the speed reading on that was 4 mph faster then the car says (so 35mph instead of 31MPH).

When we got back to the test centre she said I was speeding failed me, and went without being able ask any questions she went as as they were behind on the tests.

My driving instructor plugged her sat nav in (the exact same as the examiners use) and hers was 4 MPH slower then the cars speedometer. So between the 2 satnavs there is a 8MPH difference.


Has anyone else come across this before?

Is it right that examiners only use sat nav speedometer readings now?

If so Does that mean I should use the sat nav speed reading from now one?

AndyMc.....

So according to your sat nav you were speeding throughout the whole test and not just at one point in time?

neilmcl

No you should use the speedo on the car. At the end of the day you were speeding, whether it was 31mph or 35mph. I would still have expected your driving instructor to query this with the test centre though. Was this the examiner's own sat nav they brought into the car?

stator

It's possible for a satnav to be wrong. If you weren't stationary when it was first turned on an synchronised then it will be inaccurate. Also if there was a poor signal at the time, due to being in a very built up area.
Appeal and you might get your test fee refunded.
You'll still have to take the test again.

wongataa

stator wrote: »

It's possible for a satnav to be wrong. If you weren't stationary when it was first turned on an synchronised then it will be inaccurate.

You won't see a speed on a sta-nav until it has got satellite lock so this is irrelevant.

stator wrote: »

Also if there was a poor signal at the time

This is correct but if this isn't the case then the sat-nav speed will be accurate.

wongataa

samba987 wrote: »

My driving instructor plugged her sat nav in (the exact same as the examiners use) and hers was 4 MPH slower then the cars speedometer. So between the 2 satnavs there is a 8MPH difference.

The only way you can compare sat nav speeds between two devices and a car speed is to have them both on and running at the same time while you are driving as you need to see the numbers from all units for the same vehicle speed, on the same bit of road.

nomoneytoday

Usually a car speedo would over read and the sat nav would be the accurate one.
Could you see the sat nav speedo?

DoaM

neilmcl wrote: »

Was this the examiner's own sat nav they brought into the car?

That's how I read the OP, but it does surprise me ... why would they need one? (If it's for judging speed then it's not a calibrated device therefore cannot be used for speed measurements - only for guidance).

Mercdriver

Surely this would mean that there is a problem with the car's speedo - i.e. it's under reading the speed, not over reading it, which is not allowed...

Mercdriver

DoaM wrote: »

That's how I read the OP, but it does surprise me ... why would they need one? (If it's for judging speed then it's not a calibrated device therefore cannot be used for speed measurements - only for guidance).

New parts of independent driving in the test where the candidate is required to follow directions via a sat nav.

AdrianC

DoaM wrote: »

That's how I read the OP, but it does surprise me ... why would they need one? (If it's for judging speed then it's not a calibrated device therefore cannot be used for speed measurements - only for guidance).

Following satnav instructions is a part of the test now - and has been since December.

Depressing, isn't it?