Average speed cameras on M25 - working or not?
Discussion
I always travel at 50mph through the average speed camera zones on the M25. Currently many miles long. Yet half the population speed right past me. Either these people know the cameras do not work, or have no clue to the meaning of the word average. Which is it? Has anyone on here ever received a ticket from these M25 average speed zones?
Is it that they're blasting past well in excess of the limit, or just look like it? Assuming the system works on the limit+10%+3mph then you could average 57 through the whole set without worrying.
At an indicated 50 you're probably doing around 47, so a 10mph delta is possible, more if they slow down later on in the set to get the average down.
At an indicated 50 you're probably doing around 47, so a 10mph delta is possible, more if they slow down later on in the set to get the average down.
St John Smythe said:
A mate of mine got a ticket a couple of years back so yes, they do work. However, driving back from Kent through them on the weekend, it appears a small percentage of drivers believe they don't as they drove past 60mph+.
+1A friend of mine (and yes, I mean a friend, not "a friend") got a ticket so they clearly do something.
However, my understanding is that the limit is only enforced when it is presented overhead in a red circle (like a speed limit sign). If it is displayed without a red circle, then it is advisory, and not enforced. Can anyone confirm or deny this?
AmitG said:
However, my understanding is that the limit is only enforced when it is presented overhead in a red circle (like a speed limit sign). If it is displayed without a red circle, then it is advisory, and not enforced. Can anyone confirm or deny this?
This is correct, but only applies to the variable speed limit vs suggest speed signs on motorways. Average speed sections are always presented with the correct signage.
Krikkit said:
Is it that they're blasting past well in excess of the limit, or just look like it? Assuming the system works on the limit+10%+3mph then you could average 57 through the whole set without worrying.
At an indicated 50 you're probably doing around 47, so a 10mph delta is possible, more if they slow down later on in the set to get the average down.
This. You can do indicated 60 and be within the enforced limit. Otherwise why would you see half the traffic doing this? Obviously they don't get tickets or else they'd all be bannned.At an indicated 50 you're probably doing around 47, so a 10mph delta is possible, more if they slow down later on in the set to get the average down.
I thought the gantry cameras were not average speed but were just standard flash if over a certain speed type cameras. They do seem to occasionally flash although mostly they don't seem to activate at all.
The Yellow cameras they have at the roadworks definitely are average speed cameras and I've heard of people getting tickets from those.
The Yellow cameras they have at the roadworks definitely are average speed cameras and I've heard of people getting tickets from those.
otherman said:
Krikkit said:
Is it that they're blasting past well in excess of the limit, or just look like it? Assuming the system works on the limit+10%+3mph then you could average 57 through the whole set without worrying.
At an indicated 50 you're probably doing around 47, so a 10mph delta is possible, more if they slow down later on in the set to get the average down.
This. You can do indicated 60 and be within the enforced limit. Otherwise why would you see half the traffic doing this? Obviously they don't get tickets or else they'd all be bannned.At an indicated 50 you're probably doing around 47, so a 10mph delta is possible, more if they slow down later on in the set to get the average down.
truck71 said:
The gantry ones are not turned on at the moment, fill yer boots.
Any idea when they will be activated and if they will only work when the variable limit facility is in use ?I've heard stories that the cameras only work when the average limit facility is active on other parts of the M25 ???
Not sure if this is true as I'm fairly convinced they "should" go off when anything goes through them at 90+ MPH ??
I'm fascinated by how these things actually work. In a longish stretch of roadworks (like that currently between J6 and J5 of the M25), there are five or six sets of yellow cameras over the stretch. Do they look at (a) your average speed over the whole stretch; (b) your average speed between each camera; or (c) your average speed between pairs of cameras, i.e. a start and a finish camera?
To clarify in a diagram form...
if this is the stretch of road, and the yellow represents the yellow average speed cameras :
then do they take the average for this large red zone? :
or these five red zones individually? :
or these three red zones? :
Or, perhaps given that the cameras tend to point to specific lanes (so any of the cameras could miss your car depending on which lane you are in), is there an algorithm at work to figure out which cameras have seen you and then calculate your average speed between any two of those cameras?
To clarify in a diagram form...
if this is the stretch of road, and the yellow represents the yellow average speed cameras :
then do they take the average for this large red zone? :
or these five red zones individually? :
or these three red zones? :
Or, perhaps given that the cameras tend to point to specific lanes (so any of the cameras could miss your car depending on which lane you are in), is there an algorithm at work to figure out which cameras have seen you and then calculate your average speed between any two of those cameras?
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