M25 Gantry Cam - J15-16 Clockwise

[bigtone]

Hi All,

Has anyone heard of anyone being done with this cam recently? There are three cameras on the gantry covering all but the furthest right hand lane, and the lane three one did its flashity flash thing as I came through there this lunchtime. I seem to recall that although they flash, people have not been followed up for it, but I thought i'd check all the same.

Or is it a joyous 14 days to wait...

Thanks folks.

[JonRB]

It's a bit of a lottery as to whether you get a ticket or not. The camera system only has an 800-shot film capacity and uses two shots per offence, plus one more at startup and every time the speed limit changes. After the film runs out it enters "dummy mode" where it flashes but can't enforce (due to being out of film).

(I'm assuming we're talking about the variable-speed gantry cameras here?)

[bigtone]

Yes, thats them, although the variable limit wasn't in force at the time. Should have stayed in the outside lane, but was observing lane discipline. Doh.

I suppose bearing in mind not a lot of cars were going under 80-85, just got to hope the film was used up.

Thanks, Tony

[Peter Ward]

bigtone said:

Yes, thats them, although the variable limit wasn't in force at the time. Should have stayed in the outside lane, but was observing lane discipline. Doh. I suppose bearing in mind not a lot of cars were going under 80-85, just got to hope the film was used up. Thanks, Tony

I had heard -- though it could just be urban myth -- that the cams are only certified for enforcing reduced limits. See if anyone else has better knowledge.

[UpTheIron]

What is a "reduced" limit?

A limit is a limit surely - be it 20, 30, 40, 50, 60 or 70?

[princeperch]

The cameras enforce at all limit, including NSL. I do a lot of driving on the M25 ,and over the past 3 months the gantry cameras have been flashing a hell of a lot more than they used to...

I dont know if this is due to a reduced tolerance, or more people think its ok to speed past them..

In any case, I know for a fact they enforce at all limits.

Keep em peeled, especially around the guilford/heathrow area of the m25, plenty of gatsos in the 40 limit to keep you occupied...

[JonRB]

princeperch said:

In any case, I know for a fact they enforce at all limits.

Not quite. They enforce RX (Red X - lane closed), 20, 30, 40, 50, 60 and NSL. To each of those 7 discrete limits there is an independent threshold of 0-99mph. So if the threshold for the 50mph limit were 6 then the system would enforce at 56mph, whilst the NSL threshold might be 25mph, so it would enforce at 95mph.

Enforcing at NSL was NOT in the original specification, but was added partway through development. It can be enabled or disabled with a user-set flag.

The system therefore IS able to enforce NSL but whether or not it does is at the discretion of the operator.

UpTheIron said:

A limit is a limit surely - be it 20, 30, 40, 50, 60 or 70?

Indeed - you're quite correct there.


>> Edited by JonRB on Thursday 17th November 08:52

[supermono]

Lane closed? So, I'm driving along in the outside lane, there's jams in the others, and I've just passed an arrow telling me to get over. I can see the obstruction in the outside lane and it's 100 yards past the gantry with the X on it.

Rather than trying to shoehorn between cars into a non-gap, I continue past the gantry and safely indicate and drift into a proper gap.

Am I getting 3 points?

I guess it's as logical as enforcing a 70 in safe conditions.

SM

[JonRB]

To be honest, I have never seen the RX used. However, the system is capable of enforcing it if the gantry shows the Red X.

[princeperch]

JonRB said:

princeperch said: In any case, I know for a fact they enforce at all limits. Not quite. They enforce RX (Red X - lane closed), 20, 30, 40, 50, 60 and NSL. To each of those 7 discrete limits there is an independent threshold of 0-99mph. So if the threshold for the 50mph limit were 6 then the system would enforce at 56mph, whilst the NSL threshold might be 25mph, so it would enforce at 95mph. Enforcing at NSL was NOT in the original specification, but was added partway through development. It can be enabled or disabled with a user-set flag. The system therefore IS able to enforce NSL but whether or not it does is at the discretion of the operator. UpTheIron said: A limit is a limit surely - be it 20, 30, 40, 50, 60 or 70? Indeed - you're quite correct there. >> Edited by JonRB on Thursday 17th November 08:52

hmmmm. My man in the know says, that as of the last year or so all the m25 gantries enforce 'not that far off' NSL ACPO threshold limits...you were involved in the design of the software for the cams were you not?

[JonRB]

princeperch said:

you were involved in the design of the software for the cams were you not?

Yes, and the implementation too. It was a good few years ago now though. A decade ago, in fact.

I can't comment on how the system is being used "in the field", only on its capabilities at the time of my involvement. I actually left Serco just before the system went live, so I beleive there were some modifications made to my code after I left and obviously I have no knowledge of those either (or indeed any upgrades or changes since then, obviously).

>> Edited by JonRB on Thursday 17th November 18:34