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Average speed "cameras"

Community Veteran
Posts: 7,153
Thanks: 54
Fixes: 2
Registered: 30-08-2007

Average speed "cameras"

For the last couple of years or so, Average Speed Cameras have become quite common to control speed through motorway road works (and to a lesser extent are used on Major trunk roads as well) They seem to be generally quite an effective way to limit the speed of traffic -although there will always be a few who think rules are not for them- But, do you know anybody who has been prosecuted for covering the covered distance at too great an average speed? personally I've never even heard a rumour of a prosecution!!
And, is there any truth in the opinion, that simply changing lanes after being "recorded" by the first camera is an effective way to fool the system?
Experience; is something you gain, just after you needed it most.

When faced with two choices, simply toss a coin. It works not because it settles the question for you. But because in that brief moment while the coin is in the air. You suddenly know what you are hoping for.
19 REPLIES
pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: Average speed "cameras"

A very large number of people have been prosecuted for travelling to fast in SPECS camera zones.
Changing lane wont help, it is advanced Number Plate Recognition Via computer
Accuracy of Car Speedometers. The law requires a speedometer to have an accuracy of +0 to -10% so if you travel at an indicated speed of 60, your actual speed could be between 55 and 60.  In my case (Being an ex vehicle tester) I have a calibrated speedometer and also a Sat Nav that show my ground speed.  I know that I have an error of 8% and can therefore travel at that speed.  I have had people even when the inner  lanes are empty refuse to move over when they think they are travelling at the correct speed.
My Odometer is actually very nearly accurate (Thats distance)

Community Veteran
Posts: 7,153
Thanks: 54
Fixes: 2
Registered: 30-08-2007

Re: Average speed "cameras"

Quote from: pierre_pierre

I have a calibrated speedometer

I was aware of the required accuracy of "standard" speedo's (digital speedometers much favoured by French car makers, being no more accurate than analogue types) But not withstanding your very comprehensive reply, don't calibrated speedo's have to be calibrated daily to remain accurate? I "think" this is one of the checks Traffic police have to conduct each start of shift, I also "think" that speeding prosecutions have been beaten when it has been shown these checks were not carried out correctly by "Traffic"
Experience; is something you gain, just after you needed it most.

When faced with two choices, simply toss a coin. It works not because it settles the question for you. But because in that brief moment while the coin is in the air. You suddenly know what you are hoping for.
pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: Average speed "cameras"

Probably for the police who have to produce the evidence in court. 
there used to be a marked out portion of a road near me where they tested them.
Now you can check against the marker post on Motorways and Dual carriageway, generally every 100 metre apart - not always exact so check over several different 1 KM  length to make sure.  Time in seconds (approx 37 for 60 MPH)
60 MPH= 96.56064 KM/hr    3600/time to cover 1km = speed in KM/hr
It will also depend on tyre pressure, amount of wear on tyres, load in the vehicle etc, which will all effect rolling radius of the tyre.
That is one reason I cross reference with the Sat Nav reading
Does that help.  (it was part of my job description to test speedometers) 
Community Veteran
Posts: 7,153
Thanks: 54
Fixes: 2
Registered: 30-08-2007

Re: Average speed "cameras"

A few years ago, my older brother was "nicked" for doing 31mph through Wickam Market (Suffolk) by a patrol car (not Traffic) which don't have calibrated speedo's fitted. I suggested he should contest the case, as neither his nor the patrol car's speed measuring equipment was accurate enough for this to stand up in court.
For whatever reason, my brother chose not to contest it, he received a small fine, but the beak declined to endorse his licence, and mildly ticked off the police for being too pedantic.
Experience; is something you gain, just after you needed it most.

When faced with two choices, simply toss a coin. It works not because it settles the question for you. But because in that brief moment while the coin is in the air. You suddenly know what you are hoping for.
Community Veteran
Posts: 1,264
Registered: 04-04-2007

Re: Average speed "cameras"

The Average Speed Cameras on the A77 in Scotland have apparently had the desired effect, although I'm not sure if they've had an increase in fines / points etc. from them though.
I do find it amusing that depending on the camera configuration etc. you can lose your license (from clean) in one stretch of road Cheesy
jmd
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Registered: 30-07-2007

Re: Average speed "cameras"

It is not so amusing if you are the one to loose your licence - a friend of mine nearly did on the road from the Woodhead Pass to Sheffield/M1 where there are lots of these "average speed cameras"!  and as far as she was concerned she was not going above the speed limit but there was very little other traffic about,  but she just got a fine in end.
James
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Posts: 21,036
Registered: 04-04-2007

Re: Average speed "cameras"

Erm, isn't that a bit like complaining for getting arrested for burglary because you didn't think there were cameras about?
jmd
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Registered: 30-07-2007

Re: Average speed "cameras"

No, because if you remember the cameras are there and somehow still manage to go a little faster than you should, then you get nicked.  It is a very good road to put them on actually as it one than you could quite easily speed on!  I know when I use it I am very very careful about my speed.
James
Grafter
Posts: 21,036
Registered: 04-04-2007

Re: Average speed "cameras"

So, you're justifying breaking the law because it's a "good road"?
jmd
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Registered: 30-07-2007

Re: Average speed "cameras"

I did not say that because it is a "good road" that you can break the law!  I would not justify that!   I said,  or what I meant to say [if it is not clear] is that it is an ideal road for speed cameras because it is the sort of road you could easily go over speed limit on  if you are not careful [as I am]............... long straight stretches of highway.  There are some road that are like that in other places too.

edit; have you got no work to do today Jamesh?
geewizz
Grafter
Posts: 1,125
Registered: 01-08-2007

Re: Average speed "cameras"

I think it's generally considered ok to break the speed limit if you don't do it intentionally. The authorities should do some research into developing cameras that detect intentional speeding and not the innocent kind, like what jmdlp's friend was caught out doing.
James
Grafter
Posts: 21,036
Registered: 04-04-2007

Re: Average speed "cameras"

I thought that was the point of the 10% threshold?
geewizz
Grafter
Posts: 1,125
Registered: 01-08-2007

Re: Average speed "cameras"

Nah, the 10% threshold is so that you can overtake cars that stick to the speed limits.
James
Grafter
Posts: 21,036
Registered: 04-04-2007

Re: Average speed "cameras"

Fair enough.  I thought it was to cover potential speedometer errors.