M25 Variable speed limit

[Moo Moo]

Now have to drive this road everyday due to barsteward employers.

The last two days, the variable speed limit has dropped 10 mph as I was about to go under the gantry. Really annoying as I have been making an extra effort to keep to the posted limits.

Do they have a time delay before they start flashing you?

[OSGrooves]

Yes, the signs flash when they change the limit. You get a certain amount of time before the new limit is imposed. There is plenty of time to slow down.

What gets me is the way they flash people going over 80 even if they are black.

[Moo Moo]

HAven't seen the sign flashing. Looked at speed on sign. Looked at speedo. Looked at road, looked at Road Angel, looked back at sign and the blasted thing is showing 10 mph lower.

[JonRB]

As soon as the speed limit changes enforcement is disabled and a countdown timer starts. During this time the system will not (cannot, in fact) enforce.

The coutdown timer has a user-defined positive integer value. I don't think the value has a minimum (other than zero, obviously), so conceivably that value could in theory be zero minutes, but I would be prepared to bet my license that nobody in their right mind would set it to zero.

From memory the recommended value was 5 minutes, but only a current operator could tell you what it is actually set to.

[Moo Moo]

Happened again today. I must be cursed.

Also got undertaken by a police camera van while I was doing spot on the limit.

I have this road and its only been a week.

[225]

The new fun game is on the widend bit seeing all the numpties who normally sit in the middle lane STILL sit there so a 5-6 lane motorway is still in effect a dual carrageway..

[tr7v8]

You know who is awake and a regular because they know which ones don't have cameras & those that do. Get off M3-M25 ACW & the first gantry doesn't (never has had) cameras, good to look at others faces as you blast under it!
The lane discipline on it is worse than anywhere else, people sit at the overhead limit
and just stay in lane.

[steve z]

Do these cameras actually flash. Went through some yesterday at probably more than 10%+2 but saw no flash.

[motco]

tr7v8 said:

You know who is awake and a regular because they know which ones don't have cameras & those that do. Get off M3-M25 ACW & the first gantry doesn't (never has had) cameras, good to look at others faces as you blast under it! The lane discipline on it is worse than anywhere else, people sit at the overhead limit and just stay in lane.

That's possibly because the signs tell you to "stay in lane" during variable speed limits periods.

[flemke]

steve z said:

Do these cameras actually flash. Went through some yesterday at probably more than 10%+2 but saw no flash.

Definitely some do.
Easiest way to see if a gantry has cameras is to look at the reverse side of the companion gantry on the oncoming carriageway. They seem either to mount cameras on both sides or neither.

[clived]

OSGrooves said:

What gets me is the way they flash people going over 80 even if they are black.

If that were true I suspect a lot of PistonHeads would be losing their licence a couple of times a day.