Variable speed cameras - guidelines for activating

[Marigold9]

Hi all,

I'm trying, without success, to find the guidelines/protocols that govern the "turning on" of smart motorway variable speed limits/cameras.

I'm sure many of us have been happily driving along at 70mph only to see speed limit reductions and/or lane closures when nothing seems to have happened or is happening.

No accident, no blue lights, no roadworks, no orange lights, no "workforce in road" etc. etc yet speed limit dropped to 40mph and 3 of the 4 lanes closed for mile upon mile upon mile then all 4 lanes open and back to 70mph.

The only thing I can find is that they are turned on from a control room (Highways Agency?) but nothing about what circumstances allow whoever makes the decision to act.

I'm hoping that the decision is not at the whim of whoever "presses the button" but cannot find anything.

Surely there are "instructions" about when someone can change a speed limit, by how much and for how much time/distance before whatever it is that prompts the change.

I know some government Departments publish all their guidelines and "internal" instructions but I cannot find anything.

Surely the maximum speeds on the motorway network are not allowed to be changed by some unknown person whenever and however they think fit without some sort of control system in place?

Any pointers gratefully received.

Thanks in advance

[Kremmen]

When they introduce average speed or fixed cameras to protect motorway roadworks there seems to always be a very large, normally 50 sign at the start.

This is after a series of advance countdown info boards that there are roadworks ahead. A frequent partner is narrow lanes so regardless of any absence of workers, reducing the 70 to 50 is a common sense move for everyones safety.

Once I see the 50 sign I slow down to 50 = the cameras can be on or off.

As far as guidelines go, if you can see the 50 sign then assume the cameras are active, if the signs are covered then assume the cameras are off.
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[DennisN]

[MaFt]

As far as I understand the speeds are automated and controlled by various sensors on the motorway - both in the road and cameras monitoring traffic flow etc. Pretty sure there's a manual override too - I guess they'd need it for safety reasons.

As for the cameras being activated - I read that they were only active when a speed lower than National was in place (i.e. under 70mph) with the usual 10% + 2 leeway so at 50mph there'd be no flash until 57mph - which is when most car speedo's would be reading 60+ (i.e. clearly speeding). I believe there is a 30 second or 1 minute grace period from when the limit changes before the camera will snap you over the new speed - this covers for those times when the limit changes just as you're passing it.

When the speed is at National I *think* they now activate the cameras. In theory they could prosecute at 71mph seeing as that's speeding but due to innacuracies in speedo's and the amount of paperwork that would be involved to prove minor speeding tickets I think they will likely stick to the 10% + 2 - i.e. 79pm (so 82+ on your speedo).

[DennisN]

Now there’s an item with which I di’sagree. I con’sider the allowance to be 10%+2, ‘so 50mph allow’s 57 and give’s you a ticket at 58. Evidence i’s that ‘sufferer’s (criminal’s) report they’ve had ticket’s stating 36 in a 30 zone. Motorway’s will be 80, not 79.
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Dennis

If it tastes good - it's fattening.

Two of them are obesiting!!

[M8TJT]

Ju'st what i's the point you are trying to make Denni's?
It wouldn't be that the 's' used to pluralise a noun does not have an apostrophe before it as in the dreaded grocer's apostrophe would it? Or should it be grocers or even grocers's apostrophe?

[DennisN]

I forgot to add that I have now often seen managed motorway cameras flash when there is no posted limit, and it has been reported that the ones on M4 at Bristol have earned quite a few shekels at 70mph, so they are switched on for NSL.

The point I was making was that you don't get done for 10%+2, but for EXCEEDING 10%+2. And incidentally, I have always found the +2 strange - at 30mph it's quite a big extra, whereas at 70mph it's negligible.
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Dennis

If it tastes good - it's fattening.

Two of them are obesiting!!

[Marigold9]

Thanks all.

My interest is that I've followed the signs and limits and ended up in Lane 4 doing 40mph for miles - along with most of the other cars - while the trucks were in Lane 1 (yes, with a red X's over lanes 1,2 & 3) doing, I guess, 60mph.

Ludicrous and extremely dangerous.

I'm thinking that the truckers travel this length of smart motorway on a daily(?) basis and "know" that there's nothing happening so simply ignore the signs because they are perceived to be incorrect and not actually instructing that lanes 1, 2, & 3 are "hazardous" or that there is any actual, real, reason to slow down.

The phrase "Crying Wolf" springs to mind.

Now, IF the signals are activated by a human then someone, somewhere must surely have a book of instructions that says what to do and what signs/lane closures/reduced speed limits to apply.

IF they are activated by computer then similar protocols must be programmed in for the computer to "act" and change the 4 lane/70mph running.

It's this "instruction" information that I'm trying to find.

For example, say there's a broken down car blocking Lane 1.

I'm expecting to see an instruction something like:

Action:

Lane 1 to be closed - from the first "upstream" gantry or first & second etc.?

Lane 1 to have a speed reduction. Down to 60mph? 50mph? 40mph? from which gantry or for how many gantries/distance.

Changes to others Lanes?

Volumes of traffic to be taken into account when changing anything?

I would consider it unreasonable to close 3 of the 4 lanes and reducing the speed to 40 mph if there were only 20 cars/hour on that stretch but this may be appropriate if there has been a multiple shunt during rush hour with debris across several Lanes.

If there was a breakdown and the Lane wasn't closed and a collision happened would that lead to any action against the person responsible for "pushing the button" or would it just be an unfortunate incident?

Is someone/anyone actually accountable for changing the "normal" running?

Is there any Case Law? I should imagine that the Courts would require a sworn statement from the person responsible; describing their actions and how they followed the agreed process. And, by default, what that process is.

Dare I imagine that someone could change (or, indeed, be allowed to change) the normal 4 lane/70mph running because they "felt like it" or because it's a simple and highly effective way of generating speeding fines?

Thanks again.

[sussamb]

Since you seem keen to get answers on this why not contact those who run the system?
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Where there's a will ... there's a way.

[M8TJT]

And report back with your findings for the enlightenment of everyone here.

[DennisN]

[sussamb]

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