The "myth" of motorway speed tolerance

StrugglingApprentice

Is there any way to find out what the prosecution threshold is for a motorway?

I think i may have been spotted by a mobile van a tiny touch over 75

Plain white van, too All i saw was a tinted window, it wasnt until i got closer that i realised it was a camera with no signage or anything.

goonarmy

Probbably not been done then.

TrickyWicky

The 'guidelines' suggest that the motorist is given 10% + 2mph tolerance for speedo errors and equipment errors etc. In your case that would be 77mph so I wouldn't worry too much.

Moons ago I got flashed by a gatso speed camera in a 30 zone - I was doing 27 mph past it and it lit up the night sky like it was day time lol. I was scared stiff for weeks knowing I'd have no defence against it but nothing ever came through the post.

Aretnap

StrugglingApprentice wrote: »

Is there any way to find out what the prosecution threshold is for a motorway?.

Page 8

http://www.acpo.police.uk/documents/uniformed/2013/201305-uoba-joining-forces-safer-roads.pdf

ie in a 70 limit you will not usually be prosecuted unless your speed (as measured by the device, which is likely more accurate than your speedo) is 79mph or greater.

Richard53

There is no prosecution theshold as such. 71 mph and you are breaking the law and open to prosecution - technically.

Two things in your favour:

1. ACPO *guidance* is speed limit + 10% + 2, so effectively 79 mph on a motorway. But forces or 'partnerships' don't have to follow it if they choose not to.

2. Your speedometer is likely to read around 5% fast on average, so if it was reading 75 you were probably only a touch over a genuine 70 anyway.

force_ten

was it a mobile safety camera van?

if it was an unmarked van then i would have said it is more likely to be an ANPR van that was checking tax insurance and police markers

marlot

StrugglingApprentice wrote: »

Is there any way to find out what the prosecution threshold is for a motorway?

I think i may have been spotted by a mobile van a tiny touch over 75

Plain white van, too All i saw was a tinted window, it wasnt until i got closer that i realised it was a camera with no signage or anything.

Speedos are not allowed to read low, but usually read high.

If your speedo said 75 you were probably doing about 70.

missile

marlot wrote: »

Speedos are not allowed to read low, but usually read high.

If your speedo said 75 you were probably doing about 70.

Speedos are more accurate than you suggest.

CKhalvashi

missile wrote: »

Speedos are more accurate than you suggest.

According to Garmin GPS, mine is about 1mph out, car is on a '62' plate.

Drove a 'W' plate Focus last week with the same Garmin unit, and it's 3-4% out, so again not a big deal.

CK

Richard53

Ever since I have had a GPS, I have checked my speedometers, both cars and bikes. I have found them generally to read between 3% and 6% fast. Since the legal tolerance is -0%/+10%, it would make sense for manufacturers to aim for the mid-point of the range of tolerance, which would be +5%. This agrres roughly with my own observations.

Best car was a Range Rover, which was about 1% high, and an ex-Police Honda bike, which had a calibrated speedo and was dead on accurate. Tested up to 140 (yes, on a German motorway) and it was near enough, within 1 or 2 mph. I had too much going on to look closely.

007stuart

Don't rely on GPS to accurately record speed as it is only accurate on a dead level road, any incline or decline will throw out accuracy.