The Student Room Group

Average speed cameras

Is they a tolerence on the cameras becasuse I went from single lane to a dual carriage way with a central reservation( my understanding you can go 70mph with a central reservation) but the first camera is very awkward and sits on the single lane then the next camera is on the dual carriage way, now I sped up over 60mph before it went to dual carriage way then on too 70 on the carriage way, should I expect a ticket? or will the camera give me a few mph of tolerence?
Depending on the police force they sometimes give 10% + 2mph but you never know really. I went through a patch on the motorway cruising through a 50 zone at 60 (Knowing the speedos read a few mph above anyway) for over 1 year without problems. Then one of the days I got something through the post and ended up on a speed awareness course.
Reply 2
Original post by Anonymous
Is they a tolerence on the cameras becasuse I went from single lane to a dual carriage way with a central reservation( my understanding you can go 70mph with a central reservation) but the first camera is very awkward and sits on the single lane then the next camera is on the dual carriage way, now I sped up over 60mph before it went to dual carriage way then on too 70 on the carriage way, should I expect a ticket? or will the camera give me a few mph of tolerence?


Could you show us the road on Google Maps please so we can advise further.
Original post by College_Dropout
Depending on the police force they sometimes give 10% + 2mph but you never know really.


You can google up the specific police forces speeding policy, they usually publish it and tell you if they adhere to the NPCC's guidelines or not.
Reply 4
Original post by IWMTom

(Original post by IWMTom)Could you show us the road on Google Maps please so we can advise further.

E57AF8BF-31D3-4EC1-B42F-724DFA154CF5.png As you can see the first camera is in an awkward position so I don’t know how the second will work with my speeds.
Firstly, your speedometer is more than likely overestimating your speed by 2-4 MPH.

Secondly, the camera's aren't accurate enough. Contrary to scaremongering over the last few years, you'll get 10%+2MPH. That'll stay the same until they can produce better camera's, but then that would cost wouldn't it.
Reply 6
Original post by EL_B
E57AF8BF-31D3-4EC1-B42F-724DFA154CF5.png As you can see the first camera is in an awkward position so I don’t know how the second will work with my speeds.

Average speed cameras work in groups of two. The first camera you see on the dual carriageway section is the START camera for that section of road. Your speed between the last camera and that camera is not calculated.
Reply 7
Original post by RegisteredBMS
Firstly, your speedometer is more than likely overestimating your speed by 2-4 MPH.

Secondly, the camera's aren't accurate enough. Contrary to scaremongering over the last few years, you'll get 10%+2MPH. That'll stay the same until they can produce better camera's, but then that would cost wouldn't it.

10%+2mph has nothing to do with the accuracy of speed cameras; contrary to what you say, speed cameras are remarkably accurate.
Original post by IWMTom
10%+2mph has nothing to do with the accuracy of speed cameras; contrary to what you say, speed cameras are remarkably accurate.


An independent study on the technology behind them indicated that the margin of error was 6.7%.
Reply 9
Original post by RegisteredBMS
An independent study on the technology behind them indicated that the margin of error was 6.7%.

Cite your sources, because that's absolute nonsense. Speed cameras are calibrated for a reason.
Original post by IWMTom
Cite your sources, because that's absolute nonsense. Speed cameras are calibrated for a reason.


Calibration does not mean there is no margin of error, it just reduces it as far as possible. The technology is still the limitation.

I can calibrate an analyser at work that is used for the detection of sodium in serum. Does that mean there is no margin of error? Absolutely not.
Reply 11
Original post by RegisteredBMS
Calibration does not mean there is no margin of error, it just reduces it as far as possible. The technology is still the limitation.

I can calibrate an analyser at work that is used for the detection of sodium in serum. Does that mean there is no margin of error? Absolutely not.

There is a very very slim margin of around 2mph at an absolute maximum - 6.7% is nonsense, as is 10%+2mph.

Your theory of 6.7% holds true only at 30mph.

Please avoid spreading misinformation.
Reply 12
Original post by IWMTom
There is a very very slim margin of around 2mph at an absolute maximum - 6.7% is nonsense, as is 10%+2mph.

Your theory of 6.7% holds true only at 30mph.

Please avoid spreading misinformation.

And another one bites the dust..
Reply 13
Original post by xDron3
And another one bites the dust..

You're my new favourite.
Reply 14
Original post by IWMTom
You're my new favourite.

Honestly mate I come on here to see if I can help at all and 99% of the time you've already given an answer, helped the OP and shut down anyone who's wrong. It's impressive :laugh:
Original post by RegisteredBMS
Firstly, your speedometer is more than likely overestimating your speed by 2-4 MPH.

Secondly, the camera's aren't accurate enough. Contrary to scaremongering over the last few years, you'll get 10%+2MPH. That'll stay the same until they can produce better camera's, but then that would cost wouldn't it.


**** sakes... That's the NPCC's guidelines for starters, no police force is forced to abide by the guidelines. They can legally fine you for anything 1mph over the limit if they choose to.
Original post by IWMTom
There is a very very slim margin of around 2mph at an absolute maximum - 6.7% is nonsense, as is 10%+2mph.

Your theory of 6.7% holds true only at 30mph.

Please avoid spreading misinformation.


Because I plucked 6.7% out of the air? Ok. I heard you're only right 4.3231% of the time.

The 6.7% statistic was actually based on a study that worked out the margin of error on the technology behind the camera (note, not the camera) and 6.7% was the average margin of error for speeds at 10mph intervals from 10 to 70.
Original post by Anonymous
Is they a tolerence on the cameras becasuse I went from single lane to a dual carriage way with a central reservation( my understanding you can go 70mph with a central reservation) but the first camera is very awkward and sits on the single lane then the next camera is on the dual carriage way, now I sped up over 60mph before it went to dual carriage way then on too 70 on the carriage way, should I expect a ticket? or will the camera give me a few mph of tolerence?


Would it not just be easier to look at the speed limit of the read which is always marked when you enter an average speed check area then stick to it?
Reply 18
Original post by RegisteredBMS
Because I plucked 6.7% out of the air? Ok. I heard you're only right 4.3231% of the time.

The 6.7% statistic was actually based on a study that worked out the margin of error on the technology behind the camera (note, not the camera) and 6.7% was the average margin of error for speeds at 10mph intervals from 10 to 70.


Absolute nonsense - the Government impose a restriction on the upper inaccuracy level for a speed camera to be type approved for use, which is 2mph.
Original post by RegisteredBMS
Calibration does not mean there is no margin of error, it just reduces it as far as possible. The technology is still the limitation.

I can calibrate an analyser at work that is used for the detection of sodium in serum. Does that mean there is no margin of error? Absolutely not.

Calibration can be for both accuracy and precision, and from calibration certificates I've seen for speed cameras, the requirement is that the reading must agree to within +/- 1mph of the simulated speed, with at least five speeds from at least a range of 20mph to 80mph used. So stating a % error here is largely meaningless.

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