Third speeding ticket in six months!!

[psychocandy]

As somone else already pointed out, you've got the error the wrong way around. I always set cruise control at limit+10%, so 33 in a 30 zone. My TomTom shows me as exactly on the speed limit then, i.e. my speedometer is exactly 10% out. I sail through cameras without a single touch on the brakes, unlike most of those around me.The chief frustration of this kind of driving is that I'm constantly in danger of ending up the backside of people who believe their speedometers. Then when I change lane to try to overtake, I end up with someone up my backside because I'm reluctant to speed to avoid holding them up. (If you do 50 it takes a long time to overtake someone doing 47. I often do end up putting my foot down, for a bit.)

(I'm disappointed that no-one has come back or elaborated on the observation someone made that using cruise control is illegal. I use it all the time, and have no intention of stopping, but would be interested to learn more.)

Always wondered how accurate GPS speeds are also? Are you saying that the speed your GPS tells you is spot on?

If so, on both my cars I reckon the speedos are reading about 10-12% low which seems to be what people are arguing here.

[SimonMac]

Always wondered how accurate GPS speeds are also? Are you saying that the speed your GPS tells you is spot on?

If so, on both my cars I reckon the speedos are reading about 10-12% low which seems to be what people are arguing here.

The GPS will only give you an exact speed if you are on a perfectly level road, any incline or decline will give you a false positive.

[VectraMan]

The GPS will only give you an exact speed if you are on a perfectly level road, any incline or decline will give you a false positive.

WHS. It used to be that GPS speed was a bit of a guestimate; the GPS snooper I had would always lag 5 or 6 seconds behind when accelerating or braking. But at a constant speed it more or less agreed with the speedo of the car I had at the time, which was disapointing. I was hoping to find it was 10% out so could drive everywhere a bit faster.

[Halo Jones]

I always set cruise control at limit+10%, so 33 in a 30 zone. My TomTom shows me as exactly on the speed limit then,

I used to do this but then read in the Tom-Tom manual: where is says “speed measurements are for guidance only and should not be used as a replacement for your speedometer” (or words to that effect )

[SimonMac]

WHS. It used to be that GPS speed was a bit of a guestimate; the GPS snooper I had would always lag 5 or 6 seconds behind when accelerating or braking. But at a constant speed it more or less agreed with the speedo of the car I had at the time, which was disapointing. I was hoping to find it was 10% out so could drive everywhere a bit faster.

So why would you automatically assume the GPS was right rather than your Speedo? Or is it a case of you picking the device that was showing you the speed you wanted?

[darmstadt]

Only managed to clock 257kmh this morning due to some bedwetter in a 5 series not pulling over quick enough. Slowed down to 130 kmh where the sign said said so but he continued on at over 150, I hate people like that.

[d000hg]

They use GPS as part of race-car telemetry so it's probably pretty trustworthy

[Paddy]

Use a stop watch and marker posts. The GPS tends to be more accurate.

[EternalOptimist]

Only managed to clock 257kmh this morning due to some bedwetter in a 5 series not pulling over quick enough. Slowed down to 130 kmh where the sign said said so but he continued on at over 150, I hate people like that.

were you using the tom tom, or the jerry jerry ?

[SimonMac]

They use GPS as part of race-car telemetry so it's probably pretty trustworthy

I bet their GPS cost's more than a £100 TomTom though