Motoring question on variable speed limit cameras

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Not cycling related, hence the past in Cafe, but I figured if anyone on the net knew, it's probably someone on this site! Ironically I bet a few would expect me to know, but the police really have little to do with them.

Variable speed limit gantry cameras. Was going through one today showing 60, at 60. About ten metres before I went underneath it, it changed to 50. Now, I know I didn't get flashed and aren't in the slightest bit worried about that, but it got me thinking - these things are presumably set with a time delay so people such as myself won't get an unfair ticket, and I wondered what the time delay is before the camera resets itself was. Anyone know?
 

dan_bo

How much does it cost to Oldham?
Obviously, it would be a reasonable time.
 

simon.r

Person
Location
Nottingham
Good question, I often drive on a section of the M1 with a variable limit and I've asked myself the same question. I assume a fairly lengthy delay, but would like to know the answer.
 

classic33

Leg End Member
M6 Motorway Junctions 8A to 10A Actively Managed.....Regulations 2010 said:
4. — (1) No person shall drive a vehicle on a section of a road which is subject to a variable speed limit at a speed exceeding that indicated by a speed limit sign.

(2) A section of a road is subject to a variable speed limit in relation to a vehicle being driven along it if—

(a) the road is specified in Schedule 2;
(b) the vehicle has passed a speed limit sign; and
(c) the vehicle has not passed—

(i) another speed limit sign indicating a different speed limit; or
(ii) a traffic sign which indicates that the national speed limit is in force.

(3) In relation to a vehicle, the speed limit indicated by a speed limit sign is the speed shown at the time the vehicle passes the sign, or, if higher, the speed limit shown by the sign ten seconds before the vehicle passed the sign.

(4) For the purpose of this regulation a speed limit sign is to be taken as not indicating any speed limit if, ten seconds before the vehicle passed it, the sign had indicated no speed limit or that the national speed limit was in force.
[ Edit - the M25 Regulations specify the same 10 seconds (doesn't stop the cameras from being set to 60 seconds, mind)..]
 

classic33

Leg End Member
See also http://www.ukpoliceonline.co.uk/ind...-the-ha/?&p=419364&hl=Birmingham&fromsearch=1&
Thank you for your call to the Highways Agency Information LIne regarding the current works on the M6. I am responding on behalf of the Birmingham Box Managed Motorway (BBMM) Phases 1&2 scheme which is being implemented at Junctions 4 - 5 and J8 - 10A.

In response to your questions:

1) Junctions 4-5 is scheduled for completion and hard shoulder running by Dec 2009
Junction 8 - 10A is scheduled for completion Spring 2011

2) This is how the system works:
The main purpose is to manage congestion. It can however also be used to manage the traffic around incidents on the motorway.

The two main components are variable speed limits, or controlled motorways, and hard shoulder running.

During normal motorway conditions, with no incidents or congestion, all the electronic signs will be blank and all normal motorway rules apply.



As congestion begins to build up, or an incident is detected, the sensors underneath the road surface will detect slower moving traffic and the computer system calculates the most appropriate speed for the traffic. This speed limit will then appear on the overhead signals, with a red ring surrounding the number indicating that it is a mandatory speed limit. A red cross will appear over the hard shoulder indicating that the lane should not be used except in the event of an emergency or breakdown.

By reducing the speed on the motorway we are able to smooth the flow of the traffic, reducing stop-start driving conditions. Reducing speeds also helps prevent breakdown of traffic flow and increases traffic throughput. The uniform speed across all three lanes also reduces the need for drivers to change lanes.



If congestion continues to build up the sensors will alert operators in the regional control centre that hard shoulder running may now be appropriate. The operator will then be taken through a semi-automated system using CCTV cameras to check the hard shoulder is free of debris and vehicles. From the first alert the hard shoulder between any two junctions can be opened within minutes, giving an extra running lane to provide additional capacity at the busiest times of day.

When the hard shoulder is open to motorists a speed limit appears on the electronic signal above the hard shoulder. The speed limit will be the same across all four lanes, again reducing the need for drivers to change lanes. A message will also appear on the electronic driver information signs to inform motorists that the hard shoulder is available for use. In the event of an emergency or breakdown, you should use one the emergency refuge areas.





3) When the speed cameras are in operation there is a built in 60 second time delay from the switching of the sign/speed limit to when the cameras will actually enforce at the new speed.

More info on the scheme can be found at http://www.highways....ledge/1356.aspx

If you have any other queries regarding this scheme please forward them to our project email at: BBATM@highways.gsi.gov.uk

Regards

Persons name
Business & Information Manager
BBMM 1&2
C5 Broadway, Broad St
Birmingham
B15 1BL

All credit goes to the HA for a very efficient and highly professional response.
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Cubist

Still wavin'
Location
Ovver 'thill
As a coincidence to the thread about 12 18 months ago I was on the M6 near B'ham and the gantry speeds were all over the place. One read 40, another 50, then back to 40 with a random 60 then back to 40. I got flashed doing 55 when the gantry said 60. I was fully expecting a NIP and was ready with some facts and times ready for a bit of a scrap, I never got it, so someone somewhere must have known about the cock ups.
 

Tyke

Senior Member
As a coincidence to the thread about 12 18 months ago I was on the M6 near B'ham and the gantry speeds were all over the place. One read 40, another 50, then back to 40 with a random 60 then back to 40. I got flashed doing 55 when the gantry said 60. I was fully expecting a NIP and was ready with some facts and times ready for a bit of a scrap, I never got it, so someone somewhere must have known about the cock ups.
The M62 has just been changed to a controld system near me and the signs have been like this off and on for weeks. Looks like they are still playing with the system after it has been put into use.
 
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