Average speed in road-works.

[larus]

Anyone know how these camera systems function in road-works where they say about the average speed.

For example, on the M1 there are some by J26-28, with a speed limit of 50. I average nearer 60, and I'm OK. There have been people who have gone past me doing probably 65-70.

So; how mach leeway do they give?
Do they work on your average over the whole stretch, or treat each interval camera as a separate check?

 

[lost in london]

I always presumed they time you going in, time you going out, work out your average speed over the known distance between the cameras and fine you if you were being naughty.

 

[severnside gull]

they are usually pretty tight as the cost of putting them up then dismantling them needs to be covered plus a few £100K profit. I think it was a set on the M11 that made over £1m in a few weeks.

not sure how long it takes for tickets to come through though.

 

[dougdeep]

A lot of them don't work at all, they are just there as a visual deterrent.

 

[gullshark]

The cameras are usually a mile apart each and they note how long it takes to pass between them, hence working out the average speed. Contrary to popular belief those types of camera will catch you if you slow down when you pass em and speed back up again.

 

[beorhthelm]

Contrary to popular belief those types of camera will catch you if you slow down when you pass em and speed back up again.

of course they will, if anyone believes this dodge they dont understand "average speed" and i wonder if they should be allowed on the road at all.

 

[Arthritic Toe]

Ah good question - I've wondered this too. My suspicion is that they don't do anything automatically. The technology would need to be quite sophisticated. Plate recognition at both ends. Each camera would have to be legally provable to be callibrated correctly. The distance between them legally provable. All quite pricey for temporary roadworks. They just look like standard traffic control video cameras to me. My guess is that they may just have a bod in a control room who may look at a particular car that appears to be going fast and, clock the approx ave speed when he goes through the other end. They may then notify a waiting traffic cop in a patrol vehicle. I've never heard of anyone getting a ticket as a result of these things.

 

[gullshark]

of course they will, if anyone believes this dodge they dont understand "average speed" and i wonder if they should be allowed on the road at all.

You'd be suprised... say there were 4 SPECS cameras, my mate thought they take your average speed calculated from how quick you went through each four, so would speed up and slow down. tit.

 

[Skint Gull]

Average speed camera's are the only time to use Cruise Control. Anyone who goes more than 3 or 4 mph faster throug those is a tit.

They don't need any calibration at all I don't suppose because they'll no doubt have built in GPS to prove to about a foot where they are positioned so it's very easy for them to prove how fast you've travelled as soon as the camera recognises your plate

 

[Taybha]

stick to the speed limit your be fine simples

 

[WATFORD zero]

As soon as you pass one, pull into the hard shoulder and read the paper for 5 mins, then do 95 down the outside lane until you get to the next one

 

[Lord Bracknell]

Average speed is much simpler to calculate (and prove) than the actual speed at a single point. All you need is a couple of synchronised clocks and the capability of recognising number plates.

If the cameras are 1 mile apart and the speed limit is 50mph - anyone who passes the second check point within 72 seconds of passing the first check point is travelling faster than the speed limit.

All they have to do then is set a threshold for imposing a penalty. 65 seconds?

Before the invention of the speed camera, the police used to enforce speed limits using time travelled over a measured distance. This might be new technology, but it uses exactly the same principles as were worked out in the 1930s.

 

[Lord Bracknell]

As soon as you pass one, pull into the hard shoulder and read the paper for 5 mins, then do 95 down the outside lane until you get to the next one

I rather like that idea. It completely destroys the whole point of speeding, which I always thought was to get to your destination faster than you would if you drove safely.

 

[Uncle C]

A lot of them don't work at all, they are just there as a visual deterrent.

Only mugs take the gamble

 

[Uncle C]

For example, on the M1 there are some by J26-28, with a speed limit of 50. I average nearer 60, and I'm OK.

Why do you feel the need to speed?

 

[Arthritic Toe]

Average speed is much simpler to calculate (and prove) than the actual speed at a single point. All you need is a couple of synchronised clocks and the capability of recognising number plates.

If the cameras are 1 mile apart and the speed limit is 50mph - anyone who passes the second check point within 72 seconds of passing the first check point is travelling faster than the speed limit.

All they have to do then is set a threshold for imposing a penalty. 65 seconds?

Before the invention of the speed camera, the police used to enforce speed limits using time travelled over a measured distance. This might be new technology, but it uses exactly the same principles as were worked out in the 1930s.

Actually I think maths was invented even earlier than 1930

I still reckon there's a plod in a portacabin watching 2 tv screens.

If you've ever had a ticket from one of the fixed cameras, they are stringent in terms of the calibration date of the device etc. They have to be or some smart-arse lawyer will challange the evidence. These average speed camera's are tiny things waving about on the top of high poles, shunted around by the workman as the roadworks move around. There is no way their evidence would be enforcible under the law.

 

[Billy the Fish]

The technology would need to be quite sophisticated. Plate recognition at both ends.

Notice the infra-red lighting on them so they can see you at night, yes it is very sophisticated but it's been around for ages. There is numberplate recognition everywhere, OB cars have it to flag up stolen or suspect vehicles, there are car tax checkpoints that know if your car is untaxed and it's how the congestion charge cameras know you've driven into the charging zone.

 

[gullshark]

I dislike the fact that some speed limits are too low for the conditions, 60-70mph on dual carridgeways in bright, dry sunshine in modern cars is needless, bear in mind the 70mph limit was set when cars had drum brakes all round and absolutely bugger all safety features.

No excuse for hooning around built up areas and roadworks where there might be people working that you can mow down should you lose control - but on motorways the speed limit is a little too low imo.

 

[Arthritic Toe]

Notice the infra-red lighting on them so they can see you at night, yes it is very sophisticated but it's been around for ages. There is numberplate recognition everywhere, OB cars have it to flag up stolen or suspect vehicles, there are car tax checkpoints that know if your car is untaxed and it's how the congestion charge cameras know you've driven into the charging zone.

You'll be telling me you believe in TV detector vans next!

 

[BensGrandad]

If you've ever had a ticket from one of the fixed cameras, they are stringent in terms of the calibration date of the device etc. They have to be or some smart-arse lawyer will challange the evidence. These average speed camera's are tiny things waving about on the top of high poles, shunted around by the workman as the roadworks move around. There is no way their evidence would be enforcible under the law.

In terms of % how many people can afford to employ that lawyer the stars use or similar, probably 5% if you are lucky, so 95% will just accept it and pay up. The odds are then stacked in favour of the enforcement authorities, they can afford to lose a couple of high profile cases and then close the loophole exposed, so that Joe Bloggs cannot use it.