I don't use the M1 south of Junction 23, but north of that, and on the M6, there are still plenty of HADECS installations. Oddly, in most cases there are no road markings to be pictured with the car, so as I understand it the cameras cannot be operational. Go figure... I still slow down if necessary, just in case.
That is for HADECS 1 and 2 installations, which are both two yellow boxes. The HADECS 3 (a single long yellow box) I don't know about, but I've seen only one of these, on the M3.
On the M25, the variable speed limit gantries no longer have cameras in their boxes, but there are some HADECS 1/2 installations. They are invariably preceded, about 200-300 yards before the cameras, by a grey pole with two or three cylindrical grey cameras on it. This is to record, for evidential purposes, the speed limit displayed when it is less than the NSL. The road markings for the old gantry box cameras are still there, and these HADECS installation are live and operational.
This is all my own perception of the current situation, Cozy, welcome to the discussion, and if I have got anything wrong, please say so.
You’re pretty accurate to be honest.
HADECS 2 and 3 are out there, I’ve never been involved with HADECS 1 but perhaps some relics exist as a deterrent. What is certain though is that HADECS 2 in England are non-operational. You can fly through a HADECS 2 site that does not have a HADECS 3 and you will be fine (insert disclaimer
).
What may interest you is that in many cases with HADECS 2 sites, only one camera was present per 3 or 4 lanes. Why? Imagine the cost of four camera’s per site. So you’d find often only lane 3 or 4 would have the camera, or whichever was most likely to have speeders in it.
HADECS 2 - one grey camera with outboard flash per lane, both mounted to a gantry. No aspect camera to overwatch gantry.
HADECS 3 - one yellow camera mounted to the left of the gantry which covers all lanes and a flash. The flash can either be a separate yellow box right next to the camera or it can be in one large box with camera/flash together. The systems are the same, it just depends on manufacturer. Two or three aspect cameras are mounted approx 150-200m before the gantry. Two for MS4 style signs (large LED sign that overhangs the carriageway) and three for a full gantry with an AMI type LED signs for each lane. One camera in each setup will be viewing the whole scene in order to provide evidence that the gantry/MS4 was lit up, and the other one (MS4) or two (AMI) will be focussed right in on the speed limit. These camera’s are connected to the HADECS 3 on the gantry and are telling it what the limit is, therefore when to activate.
As far as I know, speed detection on MS4’s has not yet had Home Office approval so if you see a HADECS 3 mounted to an MS4, you’re probably good for a while. Don’t quote me as I’m out of the game now, legislation may have passed.
The HADECS 2 needed markings on the lane to prove speed. The markings on the lane were there for photo evidence and to detect the speed.
The HADECS 3 needs no markings as it’s a little more advanced, so no markings on the road most definitely means IT IS active, don’t be fooled. It works by using both a speed and tracking radar. The tracking radar detects the size of the vehicle and between two points, drawing a digital line on the image and the speed radar detects speed of course. Together the system determines that this 2.9meter car has gone between point A and B in X time and therefore at 125mph for example. The only evidence will be two photos, one from the aspect camera to prove the limit was set and displayed, and one showing the digital lines.
Now, if no speed limit is displayed? The road is treated as NSL and as if the NSL sign is illuminated. The aspect camera will show a set of blank gantry signs, and the speed camera will show a car at 125mph passed the gantry.
The tracking radar has the ability to enforce speeds for certain vehicle types too, but that’s not approved. For example the tracking radar will detect the size of an HGV, and if it is free-wheeling at 70mph, they could be prosecuted even if the limit on the road is displayed as NSL.
The HADECS 3 system is connected to a back office which is controlled by the local police force. Within this back office the police can switch on or off the system regardless of displayed limit, and set the limit as they please if they wish, or take direction from the control centre. The reason being that if it was on all day there would be so many fines they couldn’t process them all. So they will have an enforcement strategy at certain times, or days, or when they need revenue. Most forces hate the upheaval of having all this kit installed but the financial
gains are somewhat worth it I think we’d agree. The police are also set targets by the Highways Agency as part of the upgrade. You’ll never know if a system is on or off, chance it if you will. The force can also set a threshold on the limits, above the posted limit. So a displayed 50mph for example may not be set to trigger until a vehicle goes through at 65mph, or whatever they feel like. 10% + 2mph is a real thing but maybe one day they’ll feel like setting it at 51mph, or bang on 50mph, or at 150mph only to catch the real nasty people.
Generally while road upgrade works are taking place and as part of that that speed camera’s are part of the project, the HADECS 3 won’t go live until the road works almost clear. The system will then undergo speed testing with the police where they will fly through a few times well over the posted limits. They’ll verify that the radars are accurate in terms of tracking, and time which in turn is speed.
To confused things, there are some fake sites. These sites have the HADECS 3 yellow housings installed but the aspect camera’s will be fake with no wiring, and the speed camera will not be present in the housing. Why? Again like HADECS 2, for cost, and you or I wouldn’t know so why not. The only way to spot it with one manufacturer’s system is by approaching it from the opposite carriageway, and looking right at the housing. You’ll see nothing in it where as a site with a camera would show the camera’s face, which is three small black windows that almost looks like a face (two eyes and a mouth).
I’ve probably missed some stuff, but without going all technical, that’s how it goes together.
My advice is where you see HADECS 3, do whatever the variable limit says or no more than NSL.
