Average Speed Camera Criteria
Discussion
Hi All.
I'm doing a bit of research on average speed cameras, as I have one on the M1 at J11-12 which I pass through everyday. The northbound side has intrigued me since it was put up.
Firstly, these cameras do not take a picture in relation to any road marking as far as I can tell. So there is nothing on the carriageway to say that the car is being checked from this specific point to another specific point. So how do they enforce a law that says I'm measuring you from about here, to about here?
Secondly, in every average speed system I've ever seen, the signs that define the start and finish area of the average speed zone are usually some substantial distance either side of the first and last camera location, certainly 50/100m or more beyond the cameras. The bit that has baffled me about the M1 Northbound system, is that the exit camera, which looks at the rear number plate of the car, is virtually on top of the end of zone signage. The angle of the cameras seem to me to be viewing the vehicle AFTER it has passed beyond the average speed restricted area. How on earth can the law be enforced when you take a picture of a car that is alleged to be travelling at 60mph, when it is actually in a 70mph zone at the time?
This level of intrigue now has a purpose, as my daft daughter has managed to get herself a ticket through this zone, despite going through it regularly! Unfortunately (or maybe fortunately) she did this at night. So the camera evidence just shows the rear number plate, supposedly at entrance and exit, but its pitch black and it could just be a picture of the number plate taken anywhere in the dark! There is a date and time on the exit and nothing on the entrance.
So, does anyone have any knowledge of whether the night time shot of just a number plate has any credibility and my particular view is that the exit photo taken beyond the restricted zone is worthless!
Has anyone got a daytime photo of the exit camera so I can try and verify if the picture is taken outside of the zone?
I'm doing a bit of research on average speed cameras, as I have one on the M1 at J11-12 which I pass through everyday. The northbound side has intrigued me since it was put up.
Firstly, these cameras do not take a picture in relation to any road marking as far as I can tell. So there is nothing on the carriageway to say that the car is being checked from this specific point to another specific point. So how do they enforce a law that says I'm measuring you from about here, to about here?
Secondly, in every average speed system I've ever seen, the signs that define the start and finish area of the average speed zone are usually some substantial distance either side of the first and last camera location, certainly 50/100m or more beyond the cameras. The bit that has baffled me about the M1 Northbound system, is that the exit camera, which looks at the rear number plate of the car, is virtually on top of the end of zone signage. The angle of the cameras seem to me to be viewing the vehicle AFTER it has passed beyond the average speed restricted area. How on earth can the law be enforced when you take a picture of a car that is alleged to be travelling at 60mph, when it is actually in a 70mph zone at the time?
This level of intrigue now has a purpose, as my daft daughter has managed to get herself a ticket through this zone, despite going through it regularly! Unfortunately (or maybe fortunately) she did this at night. So the camera evidence just shows the rear number plate, supposedly at entrance and exit, but its pitch black and it could just be a picture of the number plate taken anywhere in the dark! There is a date and time on the exit and nothing on the entrance.
So, does anyone have any knowledge of whether the night time shot of just a number plate has any credibility and my particular view is that the exit photo taken beyond the restricted zone is worthless!
Has anyone got a daytime photo of the exit camera so I can try and verify if the picture is taken outside of the zone?
OPsaid said:
How on earth can the law be enforced when you take a picture of a car that is alleged to be travelling at 60mph, when it is actually in a 70mph zone at the time?
Because its not measuring speed at the time. It's taking a picture of a car at the start of a set distance, and another at the end of the set distance. By using the distance/time=speed equation it can work out your average speed over the distance. If your average comes out above the posted limit, you've been speeding. Simples. esxste said:
Because its not measuring speed at the time. It's taking a picture of a car at the start of a set distance, and another at the end of the set distance. By using the distance/time=speed equation it can work out your average speed over the distance. If your average comes out above the posted limit, you've been speeding. Simples.
Yes I know that's simples. At 60mph you cover the ground at 29.33 yards per second and at 50 mph its 24.44. So if the zone is 2 miles long and you were travelling at 50mph you would be 1076 yards further back, so its hardly making any odds if there is a margin for error of say 30 yards in the measured distance. However, it would appear that the "tipping point" is 60mph, so if you happened to be doing 59.75mph then that ambiguous measurement makes the difference between a speeding ticket or not. Yes, I know its semantics and at 59.75mph you are still speeding! My point is the law deals in specifics not generalities.I think my second point is a far more valid point. Surely the camera must be taking a measurement within the restricted zone?
esxste said:
OPsaid said:
How on earth can the law be enforced when you take a picture of a car that is alleged to be travelling at 60mph, when it is actually in a 70mph zone at the time?
Because its not measuring speed at the time. It's taking a picture of a car at the start of a set distance, and another at the end of the set distance. By using the distance/time=speed equation it can work out your average speed over the distance. If your average comes out above the posted limit, you've been speeding. Simples. To the OP.
The exit and entry positions are precisely determined. At the location you mentioned the road has a system of variable speed limit cameras and variable speed limits. The average speedmeters at the location do not enforce the variable speed limits, they only enforce the temporary 50mph speed limit or other temporary speed limits that may be indicated by the road signs as required.
If your daughter has evidence that the average speed calculated for her offence has spanned more than one speed limit then she should opt to have the matter heard in court. If the evidence is your guess then that could be an expensive mistake...it's up to her. If she hasn't that evidence then a fixed penalty or speed awareness course might be her best option.
If you are certain that you have evidence that the cameras are enforcing one limit in more than one speed limit you should perhaps bring that evidence to the attention of the police.
tapereel said:
It's not "simples" if the exit camera is in the 70mph limit when the limit enforced is 60mph.
To the OP.
The exit and entry positions are precisely determined. At the location you mentioned the road has a system of variable speed limit cameras and variable speed limits. The average speedmeters at the location do not enforce the variable speed limits, they only enforce the temporary 50mph speed limit or other temporary speed limits that may be indicated by the road signs as required.
If your daughter has evidence that the average speed calculated for her offence has spanned more than one speed limit then she should opt to have the matter heard in court. If the evidence is your guess then that could be an expensive mistake...it's up to her. If she hasn't that evidence then a fixed penalty or speed awareness course might be her best option.
If you are certain that you have evidence that the cameras are enforcing one limit in more than one speed limit you should perhaps bring that evidence to the attention of the police.
Yes that is exactly my point, the average speed appears to be bridging two different speed limits. I'm going to get some pictures, see if that clarifies things at all. For the record, the limit is 50mph but the paperwork states that the speeding is effectively triggered at 60mphTo the OP.
The exit and entry positions are precisely determined. At the location you mentioned the road has a system of variable speed limit cameras and variable speed limits. The average speedmeters at the location do not enforce the variable speed limits, they only enforce the temporary 50mph speed limit or other temporary speed limits that may be indicated by the road signs as required.
If your daughter has evidence that the average speed calculated for her offence has spanned more than one speed limit then she should opt to have the matter heard in court. If the evidence is your guess then that could be an expensive mistake...it's up to her. If she hasn't that evidence then a fixed penalty or speed awareness course might be her best option.
If you are certain that you have evidence that the cameras are enforcing one limit in more than one speed limit you should perhaps bring that evidence to the attention of the police.
Isn't this the 'Managed' Motorway' section with average speed cameras at various locations to Jn12 northbound? If so, OP's daughter's speed may not have been averaged between the start and end of the restricted speed section but between cameras located within it.
Edited by Riley Blue on Thursday 12th May 18:58
tapereel said:
It's not "simples" if the exit camera is in the 70mph limit when the limit enforced is 60mph.
The OP only thinks it might be. From his description, even if the camera is reading number plates 20 metres into another speed limit, this isnt going to affect the average by any significant amount to catch someone who'd been doing the right speed though the previous section.It sounds to me like he/his daughter has been dancing at the edge of the tolerance line; and have been caught out; and are now hunting for a technical excuse to avoid the punishment.
I've got no issues with him playing the tolerances and making as much progress as possible. But you gotta accept your licks if you get caught.
Saying "well I was technically speeding, but below the tolerence level by 0.25mph" isn't a good argument.
esxste said:
The OP only thinks it might be. From his description, even if the camera is reading number plates 20 metres into another speed limit, this isnt going to affect the average by any significant amount to catch someone who'd been doing the right speed though the previous section.
It sounds to me like he/his daughter has been dancing at the edge of the tolerance line; and have been caught out; and are now hunting for a technical excuse to avoid the punishment.
I've got no issues with him playing the tolerances and making as much progress as possible. But you gotta accept your licks if you get caught.
Saying "well I was technically speeding, but below the tolerence level by 0.25mph" isn't a good argument.
I'm happy to accept that my daughter has to accept her punishment.It sounds to me like he/his daughter has been dancing at the edge of the tolerance line; and have been caught out; and are now hunting for a technical excuse to avoid the punishment.
I've got no issues with him playing the tolerances and making as much progress as possible. But you gotta accept your licks if you get caught.
Saying "well I was technically speeding, but below the tolerence level by 0.25mph" isn't a good argument.
Right at the start, I said that I was intrigued by the camera as I have always thought that the angle of the exit camera must be recording cars in a different speed limit to the restricted zone. I just think that is wrong. If the motorist is going to be penalised by "safety cameras" which are restricting speeds when there is absolutely no work going on so the "safety of the workforce" cannot apply, then they might at least have the decency to set it up correctly!
Riley Blue said:
Isn't this the 'Managed' Motorway' section with average speed cameras at various locations to Jn12 northbound? If so, OP's daughter's speed may not have been averaged between the start and end of the restricted speed section but between cameras located within it.
No, this is a 50mph safety zone where they are building a new junction, 11A.Edited by Riley Blue on Thursday 12th May 18:58
chalgravesteve said:
Riley Blue said:
Isn't this the 'Managed' Motorway' section with average speed cameras at various locations to Jn12 northbound? If so, OP's daughter's speed may not have been averaged between the start and end of the restricted speed section but between cameras located within it.
No, this is a 50mph safety zone where they are building a new junction, 11A.Edited by Riley Blue on Thursday 12th May 18:58
On my recent speed awareness course 90% of the people there had been caught in the average cameras on the M60.
I was more than surprised when a few of them had no idea that they work on average speed and not fixed speed.
Ive given up gambling on them and just set the cruise to indicated 50mph if its safe to do so.
Oddly the lorries still steam past - Ive often wondered how many get done.
I was more than surprised when a few of them had no idea that they work on average speed and not fixed speed.
Ive given up gambling on them and just set the cruise to indicated 50mph if its safe to do so.
Oddly the lorries still steam past - Ive often wondered how many get done.
Trixxz said:
On my recent speed awareness course 90% of the people there had been caught in the average cameras on the M60.
I was more than surprised when a few of them had no idea that they work on average speed and not fixed speed.
Ive given up gambling on them and just set the cruise to indicated 50mph if its safe to do so.
Oddly the lorries still steam past - Ive often wondered how many get done.
None.I was more than surprised when a few of them had no idea that they work on average speed and not fixed speed.
Ive given up gambling on them and just set the cruise to indicated 50mph if its safe to do so.
Oddly the lorries still steam past - Ive often wondered how many get done.
Trixxz said:
On my recent speed awareness course 90% of the people there had been caught in the average cameras on the M60.
I was more than surprised when a few of them had no idea that they work on average speed and not fixed speed.
Ive given up gambling on them and just set the cruise to indicated 50mph if its safe to do so.
Oddly the lorries still steam past - Ive often wondered how many get done.
Based on behaviour between and at cameras it is quite amazing how many people do not know what "average" means. I hope they all get PCNs just for this ignorance.I was more than surprised when a few of them had no idea that they work on average speed and not fixed speed.
Ive given up gambling on them and just set the cruise to indicated 50mph if its safe to do so.
Oddly the lorries still steam past - Ive often wondered how many get done.
tapereel said:
If your daughter has evidence that the average speed calculated for her offence has spanned more than one speed limit then she should opt to have the matter heard in court. If the evidence is your guess then that could be an expensive mistake...it's up to her. If she hasn't that evidence then a fixed penalty or speed awareness course might be her best option.
If you are certain that you have evidence that the cameras are enforcing one limit in more than one speed limit you should perhaps bring that evidence to the attention of the police.
Just to be an annoying pedant, and I know it's not specific to the OP's particular circumstances, you do know that average speed cameras can be set up to cover a network of different roads, with differing speed limits? I was surprised when I found this out. Luckily it wasn't me who got caught.If you are certain that you have evidence that the cameras are enforcing one limit in more than one speed limit you should perhaps bring that evidence to the attention of the police.
See this thread:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
And this website:
http://www.speedcheck.co.uk/specs3.htm
giantdefy said:
In a 50 limit the enforcement speed will be >57. If you are doing an indicated 50 you are likely doing 47/48 so anyone risking it on a GPS 56 will appear to be steaming past you.
Well according to daughters paperwork, the "presumed speed" because she has exceeded the limit is 60mph. So, in my view, the enforcement speed cannot be 57mph because again, the law deals with specifics. Whilst I accept that they can issue a "presumed speed" at 60mph and above, I can't see how the law can be right if you can get caught at 57mph and be "booked" for doing 60!So I assume that the trigger speed is 60mph on this section.
The two pictures are the entrance and exit cameras. I need a better one for the exit but you can see that the yellow pylon is only just in front of the derestricted white circle with black diagonal stripe sign.
chalgravesteve said:
Well according to daughters paperwork, the "presumed speed" because she has exceeded the limit is 60mph. So, in my view, the enforcement speed cannot be 57mph because again, the law deals with specifics. Whilst I accept that they can issue a "presumed speed" at 60mph and above, I can't see how the law can be right if you can get caught at 57mph and be "booked" for doing 60!
So I assume that the trigger speed is 60mph on this section.
The two pictures are the entrance and exit cameras. I need a better one for the exit but you can see that the yellow pylon is only just in front of the derestricted white circle with black diagonal stripe sign.
Both of those camears are inside the 50mph limit zone. Are you assuming that the exit camera is taking a picture of the cars outside the 50mph zone purely because they're rear-facing? I think you will find that the angle of the cameras allow capture of the registration number immediately before the speed limit changes. Remember that you are not supposed to speed up AFTER you have PASSED the NSL sign, not when you can see it in the distance.So I assume that the trigger speed is 60mph on this section.
The two pictures are the entrance and exit cameras. I need a better one for the exit but you can see that the yellow pylon is only just in front of the derestricted white circle with black diagonal stripe sign.
QuickQuack said:
Both of those camears are inside the 50mph limit zone. Are you assuming that the exit camera is taking a picture of the cars outside the 50mph zone purely because they're rear-facing? I think you will find that the angle of the cameras allow capture of the registration number immediately before the speed limit changes. Remember that you are not supposed to speed up AFTER you have PASSED the NSL sign, not when you can see it in the distance.
Yes the pylons are both within the zone, the entrance one is way inside, which appears to be standard on every average speed zone I've ever been through. The exit one takes the rear plate, so the vehicle has to be past the pylon in order for the picture to be taken. The angle of the camera (difficult to see on my picture) is very shallow rather than pointing steeply down. It was the shallow camera angle and the complete lack of available distance beyond the pylon to the end of the zone which drew my attention to it right from the first time it was installed many many months ago. The bridge just beyond the derestricted sign is a footbridge and I'm going to try and get a picture from there in the next day or so, as well as a better one from the road.
chalgravesteve said:
giantdefy said:
In a 50 limit the enforcement speed will be >57. If you are doing an indicated 50 you are likely doing 47/48 so anyone risking it on a GPS 56 will appear to be steaming past you.
Well according to daughters paperwork, the "presumed speed" because she has exceeded the limit is 60mph. So, in my view, the enforcement speed cannot be 57mph because again, the law deals with specifics. Whilst I accept that they can issue a "presumed speed" at 60mph and above, I can't see how the law can be right if you can get caught at 57mph and be "booked" for doing 60!So I assume that the trigger speed is 60mph on this section.
The two pictures are the entrance and exit cameras. I need a better one for the exit but you can see that the yellow pylon is only just in front of the derestricted white circle with black diagonal stripe sign.
It looks to be a few 10's of metres at least.
How far do you reckon the cameras point down the road?
Looks well inside to me, using your measurement scale.
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