What are cameras set at?

[cymtriks]

When cameras first came out they were, so we were told, set at 10% plus 2 miles per hour over the posted limit thus we had-
30 limit = 35
60 limit = 68
70 limit = 79

Is this still the case?

And just how accurate are car speedos anyway?

[LongQ]

Not easy to say these days and not certain to be consistent from force to force or partnership to partnership anyway.

I think it's a fair bet that the +2 is usually dropped - certainly at least one local force near me are doing people for 33 in a 30 when using mobile cameras so it would be fair (and safest) to assume the same for the fixed units. Tales of being done for 31 are not unheard of, especially when the partnership concerned offers 'Speed Awareness Courses'. In other words the guidelines you mentioned were only guidelines and the drive for revenue makes it easy to decide to throw them away.

Speedos, as sold in a new vehicle, are not legally allowed to UNDER READ. So the speedo reading 30 should mean you are not doing more than 30. They are also not meant to OVER READ by more than 10%. So if the speedo says 30 the road speed should not be less than 27. However I suspect some do given the number of people who travel at 25 or less these days.

You also get some variation according to tyre wear, pressure and similar. Say about 1 mph likely variability.

If you have changed any of the standard spec. - especially wheel/tyre sizes bit possibly also diff ratio and gearbox on a modified vehicle and depending on where and how the measurement is made - the speedo may not be accurate any longer and would need calibrating - or at least checking against a measured mile or something similar.

Checked against my Road Angel and Sat Nav the speedo on my Saab under reads by about 2mph at 30 and 3 to 4 mph through the range up to 70. The figures are approximate since the dial does not attempt to show 1 mph graduations and I am not prepared to sit and study it for long enough to be more precise whilst on the move!

I think you will find that most cars these days have similar tolerance levels when new. Older ones are a different matter.

BMW's are sometimes claimed to have spot on accuracy.

A GPS based system should be accurate at a constant speed once the first couple of readings have been taken after reaching that speed. On that basis the digital speedo display on my daughter's Toyota Yaris seems to be accurate within the 1 mph potential error of the fractional measurements. (Both devices only display to the nearest whole number.) How reliable that is I don't really know. It was an observation not an exhaustive test.

Hope this helps in some way.

>> Edited by LongQ on Monday 21st November 17:23

[princeperch]

cymtriks said:

When cameras first came out they were, so we were told, set at 10% plus 2 miles per hour over the posted limit thus we had- 30 limit = 35 60 limit = 68 70 limit = 79 Is this still the case? And just how accurate are car speedos anyway?

varies greatly. Some mobile units in Hertfordshire dont do you for anything *less* than 41mph in a 30mph zone. The GATSO cameras are also set mostly above ACPO guidelines i.e high 30's..

However there are some confirmed instances where cameras, especially opp north i.e Lancs etc, are issuing at 33mph in a 30..

[smeggy]

LongQ said:

All good stuff

But I would like to draw attention to the following:

LongQ said:

Tales of being done for 31 are not unheard of, especially when the partnership concerned offers 'Speed Awareness Courses'.

From SafeSpeed Forums:

Gatsobait said:

mpaton2004 said: If you refuse the SAC at 31, would you get 3pts/£60? How are they allowed to do this given it's in breach of ACPO prosecution guidelines? ....... I asked TVP specifically if refusing the course having been pinged at 31 would mean the driver would get an FPN instead and they said yes. ....

FPN at 1MPH over the limit!

Worse still is the accuracy of the LTI:

Lasertech.com said:

Speed Accuracy: +/- 1 mph (+/- 2 kph)

[echo]

getting done for 31 is not uncommon - in a 20 limit (Tower Bridge anyone?).

But I find it hard to believe that someone would get done for 31 in a 30 - anyone got anything more that hearsay?

[Flat in Fifth]

echo said:

getting done for 31 is not uncommon - in a 20 limit (Tower Bridge anyone?). But I find it hard to believe that someone would get done for 31 in a 30 - anyone got anything more that hearsay?

Never seen a 33 either; 34 is a reality though; 50 yds inside a 30 on a downhill from an NSL. Not me I hasten to add, court case.

[cptsideways]

M1 Specs are at least set at 48mph in the 40 limit

[eccles]

our local gatso is set at approx 38mph, when driving towards it, i kept edging my speed up until it went off, and its a little under 40mph on my speedo.

[LongQ]

Flat in Fifth said:

echo said: getting done for 31 is not uncommon - in a 20 limit (Tower Bridge anyone?). But I find it hard to believe that someone would get done for 31 in a 30 - anyone got anything more that hearsay? Never seen a 33 either; 34 is a reality though; 50 yds inside a 30 on a downhill from an NSL. Not me I hasten to add, court case.

As I recall someone on here posted that they (or rather their other half I think) was done by a mobile for 33 in a 30 in Nottingham and that attracted a few confirmations but without much detail. That was a few months ago.

I have also seen reports of that sort of speed attracting a NIP in LanCASHire. Such comments go back some years on one or two forums.

I suppose it could all be BS. I don't fancy running personal tests, though should it happen inadvertently I will let people know.

[LongQ]

smeggy said:

FPN at 1MPH over the limit! Worse still is the accuracy of the LTI: Lasertech.com said: Speed Accuracy: +/- 1 mph (+/- 2 kph)

There are many reports of this sort of level of (lack of) tolerance being applied in Australia - especially the State of Victoria.

Since the enforcement people seem to feed off each other - indeed I suspect they are in some sort of international competition - I see no reason to suppose that the outfits here could not come up with a simple reason for working to a very low tolerance that would be accepted by the average magistrate.

Would that such low tolerances were applied to other more serious matters along with some recognisable punishment. Probably too much to expect.

[GlenMH]

Found to my cost on Saturday that the digital highwaymen are set to go off at an indicated 35 on the A4 in to Bristol from Bath. I will see what the paperwork says when it arrives.....

Glen