[Closed] Average speed cameras on motorways - anyone been caught?

Are you doing actual 50 or indicated? The speedo in my last car was calibrated (ex police car) and I was comfortably overtaking most people by doing an actual 50.

I used to work for a company that installs them - they do work FACT.

You can lose your licence in a single stretch of roadworks - FACT.

Some are dummies - FACT.

You can sometimes evade them by switching lanes - FACT.

Some stretches of roadworks have caught tens of thousands - FACT.

I just assumed that those doing well over the limit know that there isn't another camera before they turn off?

There was a thread on this a while ago. The conclusion was that yes, people do get busted fairly regularly.

The limit won't be set at 50-dead though, it'll be more like 60 at least.
And your car speedo may overestimate your speed by quite a bit too (check against sat nav or a known distance).

There is a 15 mile (ish) stretch on A1 in North Yorks I go through 3 times a week sat on cruise control at 52mph, and still people pile past you at 60+

You can lose your licence in a single stretch of roadworks - FACT.

My mother's a magistrate and in court you'll only be done once in a single Journey so if 2 speed cameras get you in different places over 1 trip you should only get 1 penalty.

steveh - Member
Are you doing actual 50 or indicated? The speedo in my last car was calibrated (ex police car) and I was comfortably overtaking most people by doing an actual 50.

How accurate my Sat Nav is, I don't know, but considering it picks up around 8 or more satellites and always seems to know exactly where I am, it consistently has my speed at 10% less than what my car says I'm doing.

Going eastbound on that long 50mph stretch through Wales today, a load of cars shot past at around 70. "Eejits" I was thinking. Sure enough there was a couple of mile stretch at the end with no camera before it changed back to 70mph.

Whenever i drive through 50mph limits there is always someone who whizzes past at 70+mph. whys that then? do they know something i don't?

You can sometimes evade them by switching lanes - FACT.

I think they fixed that flaw. They only used to be approved (by the Home Office) to monitor a single lane:
http://www.thisislondon.co.uk/news/article-23370879-drivers-can-avoid-speeding-ticketsby-changing-lanes.do (2006)

But by 2008:
http://www.theregister.co.uk/2008/07/21/speed_camera_myth/

SatNav in the van always has me at just under 10% less than indicated too.

it consistently has my speed at 10% less than what my car says I'm doing.

So your car says 50mph and the satnav 45mph? If so that's illegal, there's a 10% tolerance on speedos in cars but it's only -10%. They can under read by up to 10% but never read over the true figure. The only exception to this might be if you've got non standard wheels on with a different diameter to the original ones which would mess the speedo up.

Tip:

Smaller camera = black & white ANPR camera recording number plate only (entry camera)

Larger camera = colour camera recording no plate and taking digital colour image for conviction purposes (exit camera)

it consistently has my speed at 10% less than what my car says I'm doing.
So your car says 50mph and the satnav 45mph? If so that's illegal, there's a 10% tolerance on speedos in cars but it's only -10%. They can under read by up to 10% but never read over the true figure. The only exception to this might be if you've got non standard wheels on with a different diameter to the original ones which would mess the speedo up.

What law is this?

use the markers on the motorway on a quiet day to calibrate your speedo at 60mph. Mine reads about 10% over, so I reckon I can do 55mph in a 50mph limit average camera section and be close enough to actual 50, even without the allowed margin that you'd get.

Can't believe the number of people who don't seem to understand what average means though.

GrahamS - Member

You can sometimes evade them by switching lanes - FACT.

I think they fixed that flaw. They only used to be approved (by the Home Office) to monitor a single lane:
http://www.thisislondon.co.uk/news/article-23370879-drivers-can-avoid-speeding-ticketsby-changing-lanes.do (2006)

But by 2008:
http://www.theregister.co.uk/2008/07/21/speed_camera_myth/

I know they were developing them to monitor multiple lanes, but I stopped working for the company and subsequently fell behind with technology. Some of the fixed ones may now do that, maybe some motorway ones do too - not sure, but I could find out.

How does that help TAFKAS? There may be mire than one pair of cameras on a stretch and they are not necessarily paired in sequence.

Can't believe the number of people who don't seem to understand what average means though.

Yeah you see a lot of people who slow down for the cameras in average zones. Unless I'm wrong don't they measure the time between cameras rather than the speed at each camera?

Tailgating a truck when approaching a camera will do the trick

So your car says 50mph and the satnav 45mph? If so that's illegal, there's a 10% tolerance on speedos in cars but it's only -10%. They can under read by up to 10% but never read over the true figure. The only exception to this might be if you've got non standard wheels on with a different diameter to the original ones which would mess the speedo up.

HGV's are limited to 56mph by law and give or take the odd 1mph (see the annoying 40ft artics overtaking on dual carriageways) I believe the limiters are quite accurate.

Sit next to one and i'll bet you a pound to a penny your speedo will read 60mph+.

I know they were developing them to monitor multiple lanes, but I stopped working for the company and subsequently fell behind with technology.

That article quote the guy from Speedcheck Services Ltd. There was never any technical limitation on monitoring multiple lanes, why would there be it's easy. The problem was just a matter of Home Office approval. According to him.

I see plenty of big trucks doing 70 on the motorway, sometimes more

Whatever you say about the cameras, they do keep traffic flowing through roadworks better than the fixed ones.

Without doubt my speedo reads to high as do they all which was the point of my post. I misunderstood your post when i first read it. Well it does on my current car, my last ex police calibrated one was bang on and rather useful.

How big funky monkey? Anything over 7.5 ton is speed limited.

GrahamS - Member
How does that help TAFKAS? There may be mire than one pair of cameras on a stretch and they are not necessarily paired in sequence.

Erm, yes they are, or at least to my knowledge they always used to be.

You don't have to listen to me if you don't want to. As I've said, I no longer have any involvement with said company, so some of my knowledge may be slightly outdated. I wouldn't want anyone to take my word as gospel, but do you seem to think you know more about them than me?

If so, pray tell - I'm all ears, as I'd like some tips to help getting caught out too (obeying the speed limit being the obvious answer).

So your car says 50mph and the satnav 45mph? If so that's illegal, there's a 10% tolerance on speedos in cars but it's only -10%. They can under read by up to 10% but never read over the true figure. The only exception to this might be if you've got non standard wheels on with a different diameter to the original ones which would mess the speedo up.

Whether it's illegal or not I don't know but I think he has it the wrong way round, as by this reckoning a reading of 50 mph might actually be 55 mph - that ain't going to be the way round it's set up now is it?

I think he may actually be correct (no of course I don't know - this is baseless supposition) but the -10% refers to the speed not the reading. A certain car mag used to give speedo reading at 70 mph in all it's test and it was normally in the 75-77 mph range.

That article quote the guy from Speedcheck Services Ltd. There was never any technical limitation on monitoring multiple lanes, why would there be it's easy. The problem was just a matter of Home Office approval. According to him.

The technical limitations would be

a) a fixed point camera looking at a single lane

b) specific calibration and point to point distance measurement.

That said, yes the technology is quite obviously there and it may well have been HO restrictions - the legalities of which I'm not sure and have no reason to doubt your quote.

The M42 active traffic management was initially designed to have average speed camera's, but this was foiled by government red tape, hence the fixed Gatsos that currently adorn the gantry's.

Erm, yes they are, or at least to my knowledge they always used to be.
You don't have to listen to me if you don't want to. As I've said, I no longer have any involvement with said company, so some of my knowledge may be slightly outdated. I wouldn't want anyone to take my word as gospel, but do you seem to think you know more about them than me?

Just going on what I've read is all. No insider knowledge.

"each section covered has a number of cameras and drivers would not be able to see which one was paired with which.
You might be picked up by entry camera A, speed down to camera B and change lane only to find that that was also an entry camera and that either exit cameras C or D would get you further down the road."
-- http://news.bbc.co.uk/1/hi/7048645.stm

Tailgating a truck when approaching a camera will do the trick

I assume you mean hiding your front number plate by lurking behind the truck? Once you have bypassed the entry camera you can nail it through the section and past the exit camera. The theory seems sound, fancy trying it?

I have also wondered about motor bikes, as they don't have front plates they can't be recorded. No?

Also:

"[u]Linked cameras do not have to be adjacent[/u]; they may bracket other cameras within the speed control zone. Despite what you may read in the press, SPECS is not lane specific, or limited to vehicles that enter and exit the zone in the same lane."
-- http://www.speedcheck.co.uk/specs.htm#how_does_it_work

And to round off my Googling:

BoardinBob: What law is this?

This one?

2.  For all true speeds up to the design speed of the vehicle, the true speed shall not exceed the indicated speed.

3.  For all true speeds of between 25 mph and 70 mph (or the maximum speed if lower), the difference between the indicated speed and the true speed shall not exceed—

V/10 + 6.25 mph

where V = the true speed of the vehicle in mph.

Also, your car speedo accuracy depends on the car massively. Compared to our sat nav (which agrees with my phone sat nav), our Audi speedo is absolutely spot on. Our Honda speedo is hugely out, it can read 78mph when the sat nav is reading 70.

Like I said Graham - just basing my comments on what I actually know to be true when I actually used to install the actual cameras in question.

Not really bothered enough to research where the current technology may, or may not be up to.

I could certainly ask the question and be given a definitive answer (direct from SPECS) within 24hrs if you are really that bothered. Personally I'm not that bothered, so I'm willing to leave it there and accept that I may, or may not be right.

TheFunkyMonkey - Member
I see plenty of big trucks doing 70 on the motorway, sometimes more

I am lead to believe that the limit is 56mph ?

Well that was the quote direct from the SPECS website so I expect they'd give you the same line (whether or not it is actually true). 😀

I'll be sticking with setting the cruise control at limit + 5% and not getting stressed about it if other people fly past. 🙂

Well that was the quote direct from the SPECS website so I expect they'd give you the same line (whether or not it is actually true).

I'll be sticking with setting the cruise control at limit + 5% and not getting stressed about it if other people fly past.

Company blurb = truth, yeah whatever 😉

I meant from someone actually in the know, not a company PR rep 😉

As for setting you CC at limit +5%, i'd say that's a sensible option and one that you wouldn't go far wrong by.

my citroen read 80 when it's doing 73 according to my sat nav. Can never understand how in the average zone odd cars are blasting past at 80.

There is a 15 mile (ish) stretch on A1 in North Yorks

Feels like it goes all the way from Scotch corner to Leeds...

most the trucks seem to keep on at 56mph through 50 limits so i guess the know what the actual limit is. most are foreign though and i know the kind of respect i have for cameras abroad!

I dont risk it as i am aware they can do you for 2mph over and the fact satnavs arent always accurate.

Work with ex-policeman, one of the courses they did was on the various forms of speed trap, they where told that the average speed cameras are set at 58

strange how we're so obsessed with this - seems like quite a lot of fuss and effort to save perhaps 1 minute off your journey time

Foreign lorries are not always limited are they?

Our Mondeo used to under-read at slower speeds (so 25mph actual would read around 23mph on the speedo) and then as you passed 30-40mph it would zero out and start to under-read to about 5% at 70mph.

My point was has anyone been caught, or know of anyone who has been caught.

It seems no one has and I have never heard of anyone who has, which seems very strange to me.

So your car says 50mph and the satnav 45mph? If so that's illegal, there's a 10% tolerance on speedos in cars but it's only -10%. They can under read by up to 10% but never read over the true figure. The only exception to this might be if you've got non standard wheels on with a different diameter to the original ones which would mess the speedo up.

Other way round, car speedo can over read by up to 10%, TBH some car manufacturers seem to do this as a matter of routine, Ford & Nissan cars have hopeless speedos in my experience. I had a Nissan terrano and for that to be doing 70mph as indicated by a sat nav, it was doing an indicated 80mph. If you drove it according to the speedo there was no chance of getting caught speeding and it helped with the fuel economy as well.

deadlydarcy - Member
Going eastbound on that long 50mph stretch through Wales today, a load of cars shot past at around 70. "Eejits" I was thinking. Sure enough there was a couple of mile stretch at the end with no camera before it changed back to 70mph

did they have blue lights and make a funny noise?

What I'd like to know is how people know that their speedo is under-reading? I mean I accept that there will be an error associated with every speedo as that is the nature of all measuring devices, but what are people comparing their speedo readings to and how do they know what the accuracy of the coomparative figure is?

What I'd like to know is how people know that their speedo is under-reading? I mean I accept that there will be an error associated with every speedo as that is the nature of all measuring devices, but what are people comparing their speedo readings to and how do they know what the accuracy of the coomparative figure is?

One assumes it's their GPS speed readings on SatNav. Anecdotally, I hear that SatNavs (given 5 or so satellites) are quite a bit more accurate than your speedo. But exactly how accurate they are, I don't know.

My point was has anyone been caught, or know of anyone who has been caught.

It seems no one has and I have never heard of anyone who has, which seems very strange to me.

My sister's mate on the M1 in norf London, near Watford.

Other way round, car speedo can over read by up to 10%, TBH some car manufacturers seem to do this as a matter of routine, Ford & Nissan cars have hopeless speedos in my experience. I had a Nissan terrano and for that to be doing 70mph as indicated by a sat nav, it was doing an indicated 80mph. If you drove it according to the speedo there was no chance of getting caught speeding and it helped with the fuel economy as well.

My old Focus used to read about 33/34 when it was actually doing 30, so I reasoned that with leniency in camera settings to allow for car mis-calibration (I was lead to believe this was 10%) that my doing 55 in a 50 with average cameras would be fine.

You can only calibrate a speedo for a certain tyre wear as the speedo guesses the speed on an assumption about distance travelled per wheel revolution.

On a small diameter tyre (say 14") the tread could vary by up to 8mm (on both sides) ie 16mm diameter variation on a 352.8mm diamater ie roughly 5% variation in speed reading over the life of the tyres...

what are people comparing their speedo readings to and how do they know what the accuracy of the coomparative figure is?

The distance markers by the roadside. Little white posts with distances marked off in tenths, so if you have a breakdown you can pinpoint your location to the rescue services.

Another Q. What are car milometers calibrated from then? If my speedo is 5% over, does that mean the 60K my car has done is really 57K?

Another Q. What are car milometers calibrated from then? If my speedo is 5% over, does that mean the 60K my car has done is really 57K?

Yep. Most probably. And you're also doing less MPG than you think too!

All I keep reading is a friend of a friend got caught etc., I usually do around 60mph in them and not been caught. Not big and not clever but still not reading about any direct experiences here...

Sat Nav's are very accurate (less than 1m a second accuracy easily). They're not computing your speed from your postion tho, they're using he dopplar shift on the signal, so not having a large number of saterlites in view has less effect on accuracy.

I seem to recall the police calibrate against sat navs.

This [url= http://www.bbc.co.uk/news/uk-wales-11937954 ]BBC report[/url] would suggest that the S Wales ones are working fine.

wiilt - Member

My point was has anyone been caught, or know of anyone who has been caught.

Monksie off here got done by a camera in some roadworks. He 'fessed up. There was a thread about it but I think it was before The Hack