Average speed cameras - how do they work?
 

They've just shoved some up near me and it made me wonder!
You see loads of people speeding up between the cameras so my question is - do the cameras record your speed as you pass each camera so as long as your doing 50mph then you're ok or do they calculate your speed between the cameras?

While I'm on - why are the highway maintenance vehicles bound by an 11mph speed limit. Seems like a random number!

Average speed, however I have read that they are not very accurate so therefore they can't set the average at say 55, it's a fair bit higher to allow for error.

I am sure someone will have a more precise explanation!

Fairly straight forward.

Speed = distance divided by time.

Set distance between A & B so at 50mph you work out the time it should take (Say 30 seconds). If it only takes 20 seconds you can work back the speed.

You do see lots of people completely ignoring the road work ones, makes me wonder if they even work.

Does anybody know of anyone caught speeding on road work average speed cameras?

I've asked the same about the variable one around Birmingham, people don't seem to slow down, but they never flash.

And apparently, changing lanes confuses them totally

Whenever im on the M6 or M1 and they have these yellow Avergae cameras up I always wonder how people are flying past me and not getting 'done'...

I've heard that too. I dont get to go on motorways much, but i always go 10 miles over what the limit for the average speed camera say.

I only realised that i could easily drive above the limit for the average speed cameras when i unknowingly drove through a set at quite a bit over, then crapped my pants for 3 weeks, waiting for something to come through the post. Nothing ever turned up!

I suspect they dont work, and are more a visual deterrent. But, i'm too scared to fully test that theory!

They do not flash when you go through them.

The first thing you will know if you have been speeding is a letter on the door mat from the DVLA

Do they work? Who knows but would you take the risk for a fine and 3 points?

I have heard this too...dot speed through the roadworks..but i do change lanes quite often when the camera's come up

i have had a fine come once..on the M25 - but that was i think 2 years back..
so they do work... maybe just when switching lanes they dont..? i just change lanes now just to be sure.. lol

Variable speed cameras DO flash; I saw it happen 2 weeks ago. They work exactly the same as normal roadside cameras, not average cameras.

BUT they only work when the gantries they are mounted on are displaying a speed. If the speed boards are turned off then they won't catch you speeding. If a speed is posted on the gantries then they will be set for that speed displayed at that particular time.

Sorry fella misread the post. Your spot on:thumb:

You are talking about two different speed camera types.Using Birmingham as an example,on parts of the M42 that are managed motorway sections,there are gantry mounted Gatsos that do flash and are live.
On the M6 (J5-8) through the roadworks,the limit is a fixed 50mph with live average speed cameras.These do not flash.
When the roadworks have been completed(June 2014),this section will then be replaced by managed motorways with Gatsos.

There is SO much mis-information going on here.

Changing lane does not "fool" average speed cameras, the older generation cameras yes it would, but the new ones it does not. So you will get nicked either way.

Average cameras are paired and you never know what lanes what camera is monitoring and what ones are linked. Do you not think the designers would have thought about this when they put them up? lol

The m25 gantries and the m6 etc are gatso's that DO flash. And it isnt necessarily just when the speed limit has been change don the boards.

They will be active at all times when the boards are displaying a limit, but bare in mind on average only 1 in 5 gantries have the cameras installed, and about the same are actually "active".

The gatsos will not operate if there is a fault with the display sign, or about 10 seconds after they have changed the limit.

The police can activate the gatsos on the m25 at any time they please from what i have researched.

And you can see what gntires have cameras as you can see the frame work behind the signs. So this is why people still speed on the m25, as they are just slowing down for the gantries with cameras on

http://lmgtfy.com/?q=why+11mph+speedlimit+in+roadworks

:)

They are a form of surveillance and I find the ANPR system which they are part of to be somewhat sinister.

Just for sakes of accuracy the ones on the M6 gantries etc (and newer M25 camaras) are not Gatsos, but HADECs. The old M25s were Gatso, the M25 now has HADECS cameras too.

They work in a similar fashion but are digital and images can be remotely downloaded...Gatsos use a roll of film, and have to be loaded by hand. The main point being Gatsos work depending on if they are loaded with film or not (or ran out), HADECs don't have film so never run out.

What jglanza V has said is exactly what ive heard. Living on the M1 you hear alot about the camaras.

I noticed last time I came up the A1 that SPECS average speed cameras are being installed on their, north of Peterborough.

Does anyone know if it's just for speed monitoring, or as part of up-coming roadworks?

Alcazar ..... There are barrier works for the next 4 weeks or so for a 2 mile section of the A1 north of Peterborough and the Specs are temporary for that period only.

The SPECS system measures average speed between pairs of cameras. Changing lanes to fool the camera is unlikely to work for the following reason;
You won't know which camera's are paired. It could be the next camera or a camera a few miles down the road.

Just to add to this it is possible to dodge the average speed camera's as they are targeted to certain points on the road, for example being half in the other lane for the zone the camera is looking at will cause it to miss your plate. Therefore not recording your car at that checkpoint for the speed.

Also a fair few don't work, for example the A13 set has been broken for some time now. I know this because my company manages the transmission station where the data is collected so I asked the guy that maintains the camera's when he came to try and fix them.

Number plates in the windscreen also confuse them.

Despite knowing all this I still don't speed through fear of them being fixed haha, they are set to 10% + 2 so your speedo would need to be on like 60ish to be caught in a 50 anyway.

My advice is just stick to the speed limit on motorways, iv'e done hundreds of thousands of miles on them and you always see the idiots that do silly speeds 5 mins down the road again most of the time as they get held up by other traffic sooner or later, even if you don't see them they only save about 5 mins on a 100 mile journey anyway so there is no point, just leave the house 5 mins earlier.;)

The only thing that driving fast on a motorway does is stress you out, either from concentrating watching for cameras, police cars and looking at the road trying to anticipate what others will do, shouting at other road users that lane hog and just generally winding yourself up.

Go to bed earlier and wake up earlier.:thumb:

Nirvana.;) :lol1:

Yes, that's why I said "They work exactly the same as normal roadside cameras, not average cameras." Because the gantry ones are just Gatsos and the average are obviously different.


Yes, ONLY active when the boards in front of them are diplaying a speed. If the boards are turned off the Gatso's are also turned off. But as you rightly point out they can be activated at any time but again, the speed board would be active as well.

I think it was on motorway cops or traffic cops the other day, they pulled a driver and he told them he had 6 points by getting caught in the average speed cameras on the m62. He got them on the same day

Similar thing happened to a lad I used to work with. He was in a company van and managed to lose his license through one stretch of roadworks in one journey! Because he thought he could slow down at every average speed camera and he wouldn't get caught!!

Thanks chief.

Top quality advice :notworthy
I do wish I could remember it when I'm on the motorways :lol1:

This advice = Rubbish

You dont know what camera is aiming at you so you cant be in its "blind spot"

Do people not htink the people who design these things are also drivers and will have spent an awful lot of R+D time figuring out ways to stop people dodging them? lol.

Seriously, some people are so niáve.

I agree they have a tolerance as i usually do 2/3mph over the limit anyway. But you never know what one is aiming at you or what ones are paired so you can try and dodge them as much as you like but you will always get had sooner or later