M25 average speed cameras (?)

[qwertyK]

Seen today there are the yellow average speed cameras set up for some future road works on the anticlockwise M25 near M11. I was always under the impression virtually all the gantries on the M25 variable speed limit areas had average speed SPECs on them?

[Chris5156]

I don't think average speed cameras are ever used to enforce variable speed limits. Smart Motorways tend to use HADECS cameras which are triggered by your speed as you pass the camera - their trigger speed can be varied depending on the limit, but they are just photographing vehicles travelling over a certain speed as they pass the camera.

[Bomag]

Quote from TSM Chapter 8 Part 3

U2.10.24 Since the spacing of the signals, particularly for Options Two and Three, will probably not be within the values identified in Table 2.1, the relevant order or Statutory Instrument must enable each signal to be considered as a terminal sign. Any enforcement must use fixed point technology integrated into the signal control equipment. Due to the variable nature of the signs, separate fixed point camera systems are not able to satisfactorily record the aspect displayed at any specific point in time. Average speed camera systems must only be used with signs at the spacing identified in Table 2.1.

[RichardA35]

My comment from experience of having designers detail up gantries on a widening scheme with several junctions is that there may be signage at every gantry. However, the locations suitable for enforcement were only when traffic was flowing remote from weaving from an onslip or for an offslip, meaning out of about 50 gantries only c. 6 were suitable locations.

[qwertyK]

What are the old type cameras on the gantries then? Not the yellow HADECS

[AndyB]

If they're grey, they're not speed cameras.

[Chris Bertram]

I'm led to believe that the HADECS2 cameras which were mounted on gantries, one per lane, were never actually operational. But I'm prepared to be corrected on that. Such cameras were also installed in some locations in the Midlands on M6 in particular.

[Truvelo]

I'm led to believe that the HADECS2 cameras which were mounted on gantries, one per lane, were never actually operational. But I'm prepared to be corrected on that. Such cameras were also installed in some locations in the Midlands on M6 in particular.

Those older HADECS cameras on the M25 between the M4 and M40 were definitely operational. Back in the day I saw them flash like mad at vehicles on the opposite carriageway that didn't appear to be travelling at much over the speed limit.

[Darren]

Those older HADECS cameras on the M25 between the M4 and M40 were definitely operational. Back in the day I saw them flash like mad at vehicles on the opposite carriageway that didn't appear to be travelling at much over the speed limit.

Similarly when I used to regularly be on the M25 at 5 AM on a Sunday, in the dark, you'd see a veritable disco on the other carriageway between junctions 8 and 10 - with those old HADECS cameras merrily flashing away. Now, whether they had any film in them was another matter!

When the newer cameras went in you'd see some flashes, but nowhere near as many as with the old "hidden behind the gantry signs" cameras.

[Chris Bertram]

Ah, so maybe it was just the ones on the M6 that were never pressed into service.

[qwertyK]

Those older HADECS cameras on the M25 between the M4 and M40 were definitely operational. Back in the day I saw them flash like mad at vehicles on the opposite carriageway that didn't appear to be travelling at much over the speed limit.

Similarly when I used to regularly be on the M25 at 5 AM on a Sunday, in the dark, you'd see a veritable disco on the other carriageway between junctions 8 and 10 - with those old HADECS cameras merrily flashing away. Now, whether they had any film in them was another matter!

When the newer cameras went in you'd see some flashes, but nowhere near as many as with the old "hidden behind the gantry signs" cameras.

There was this article in the DM from a decade ago reporting only 3 cameras worked. https://www.dailymail.co.uk/news/articl ... retch.html

Then this FOI via the govt revealed this https://assets.publishing.service.gov.u ... dacted.pdf

Seems like the white lines either remain there from when the gantries were fitted with cameras, or they are just repainted over to act as some kind of detterent.

I was always under the impression in addition to VSL cameras the M25 had average speed cameras/specs mounted on the gantries so always drove just below the limit

[AndyB]

For SPECS to work at all in a VSL area, the active cameras would have to be placed between two consecutive gantries showing the same speed. I don't know what the minimum distance certified for SPECS is, but I think the gantries are typically every 500m third of a mile?