Safe Speed Forums

So you drive slower when entering a speed camera zone?

Or do you drive above the limit right up to the camera, slow down, and then go back above the speed limit afterwards?

Every "speed camera zone" is different, every day, every drive is different. I drive within what I consider a safe limit for the day/car/conditions/time of day/how I am feeling.

If I slow for a speed camera,sometimes I will speed up again afterwards (such as a fifty or 40MPH limit on a good, previously NSL road. If it's in a n urban area during the day I will keep to a max of 30MPH throughout the area until I feel it is safe to increase my speed.

That's what good,safe driving is all about, it's not about a number on a post. I reckon a good driver can travel the length and breadth of the country without needing a speedo. They wouldn't have any accidents but they may pick up a few fines.

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My views do not represent Safespeed but those of a driver who has driven for 39 yrs, in all conditions, at all times of the day & night on every type of road and covered well over a million miles, so knows a bit about what makes for safety on the road,what is really dangerous and needs to be observed when driving and quite frankly, the speedo is way down on my list of things to observe to negotiate Britain's roads safely, but I don't expect some fool who sits behind a desk all day to appreciate that.

You yourself have missed an important point that we all have explained many times before...here it is again:
Regression to the Mean, the most obvious and widely known confounding factor of them all! How come pro-camera types always dismiss this critical factor, one on its own proven to be way more significant than the camera itself?


Do you have a decent reference for this?

That's obviously countered by the confounding factor of fatigue, already a factor in 24% of all fatal accidents on fast roads [table 1.1: DfT Road Safety Research Report No. 52], do we really want to expose drivers to less stimulating speeds - for longer?



Traffic police have been proven to be inefficacious? Really?
Is Safe Speed calling for the encouragement of joyriders and boy racers? Oddly enough, the camera policy allowed these groups to flourish.


The simple fact is: there is no conclusive proof, proof that passes simple and basic scrutiny, that cameras have any positive impact, and that's even before considering the displacement of trafpol.

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Views expressed are personal opinions and are not necessarily shared by the Safe Speed campaign

And what are the speed limits there for? Speed limits are a good thing, but do our blanket limits as they are set encourage predictable driving styles?

Speed limits are indeed an underlying factor and can cure the compliance issue (boyracers and joyriders aside, but they don’t care anyway - and cameras don’t stop them), but only when set properly.

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Views expressed are personal opinions and are not necessarily shared by the Safe Speed campaign

So how do you set that level of risk, and hence the speed limit?

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown

Ah ha! throw in an unrelated point to counter another. What's that got to do with the difference between collisions and casualties? I am well aware of regression artefacts and need no reminding of them from you.

I have lots of references but find it odd that you would need to be made familiar with them.

Finch, D. J., Kompfner, P., Lockwood, C. R. & Maycock, G. (1994) Speed, speed limits and crashes. Project Record S211G/RB/Project Report PR 58. Transport Research Laboratory TRL, Crowthorne, Berkshire
Nilsson, G. (1982) The effects of speed limits on traffic crashes in Sweden. In: Proceedings of the international symposium on the effects of speed limits on traffic crashes and fuel consumption, Dublin. Organisation for Economy, Co-operation, and Development (OECD), Paris
Nilsson, G. (2004) Traffic safety dimensions and the power model to describe the effect of speed on safety. Bulletin 221, Lund Institute of Technology, Lund
Kloeden, C. N., McLean, A. J. & Glonek, G. (2002) Reanalysis of travelling speed and the rate of crash involvement in Adelaide South Australia. Report No. CR 207. Australian Transport Safety Bureau ATSB, Civic Square, ACT
Kloeden, C. N., McLean, A. J., Moore, V. M. & Ponte, G. (1997) Travelling speed and the rate of crash involvement. Volume 1: findings. Report No. CR 172. Federal Office of Road Safety FORS, Canberra
Kloeden, C. N., Ponte, G. & McLean, A. J. (2001) Travelling speed and the rate of crash involvement on rural roads. Report No. CR 204. Australian Transport Safety Bureau ATSB, Civic Square, ACT

There is no obvious counter at all; I would say you have used the figures in the tables to form an argument that is an assumed counter but you have no credible evidence for that, perhaps you would like to advance it here.



I don't follow the Traffic Police reference, sorry, where did you get that from?
How has the camera policy allowed boy racers to flourish. Has there been an increase in their numbers beyond the demographic normal? I have no idea if there has or has not from what evidence do you make this claim?


The problem you have is that simple and basic scrutiny doesn't do the job does it? As I have shown in these few posts.

You can't simply quote a few unrelated principles and ask for references in the hope that someone who states a principle with which you disagrees will find it too hard to give an answer; in asking for the references you have you have shown that your understanding is at a basic level and it is hardly surprising that you are finding it difficult to counter with some cogent material. You need to amass some worthwhile references of your own to support your campaign as I have masses of them to support the counter to it. References with safespeed.org.uk don't cut it I'm afraid. Look wider.

So the cameras completely failed to stop these offences being commited. More than this, the system allowed this person to go on and commit a further offence before being aware of the first one.
[/sarcasm]
Well I must say, I thought that cameras didn't work - this sells it to me finally!
[/sarcasm]

The only thing I can see from your posts is that you aren't reading the answers, and posting spurious information that is unrealated doesn't help.
As I said in an earlier post, please convince me that accidents that are not caused by speed can be prevented by regulating speed.

Speed limits would aid predicatbility if they were generally observed. The limit being a maximum and speed choice is a safe speed below the maximum.

Speed limits are generally set properly. Because some drivers who want to exceed them because they see no obvious need for the limit is not a jsutification that the limit is incorrectly set. If the hazard is permanent but conditional on other factors such as hourly flow then unless a variable limit applies the fixed limit is...well it's fixed. That doesn't not say that it is incorrectly set.

You seem to be angling for setting the limit at a level that drivers would observe and to raise it until that point is reached. That isn't practical nor is it safe. Perhaps you could make some form of proposal to show how that would be done in a safe, practical and affordable way.

You would need a traffic engineer to quantify that.

How many times can you explain before when you have only posted 47 times before?

OK quick one for you based upon this point of view. Last week I drove along a section of road that carries a 40mph limit at around 35-40. In your opinion, would I be safe to do this again this week provided the traffic conditions were the same?

The argument that the automatic camera lets you carry on offending is nonsense; of course you carry on but the sensible alter their driving habits when they receive their ticket. If they are unlucky to get 2 before that happens then that doesn't prove the argument.
Of course there are some who even get caught in the same camera more than once; does that mean that the cameras are useless? I rather think the finger of accusation is pointed in the wrong direction.

It's in there.

That would be a matter for you to judge but I would say: you may be as safe, if in your opinion the traffic conditions were the same. The results may not be the same of course, therein lies the risk.
I await the closing of your trap with mild interest.

I don't think you have read the answers; I explained quite clearly that the prevention of speed related collisions was not the primary purpose or principle with which the reduction of serious and fatal casualties was achieved by the use of speed enforcement systems. Quite clearly this has passed you by. If you would care to comment on my explanation of this then please do as I contend that it answers your question.

oh, I beg to differ there.

The old A120 at Takely, was an NSL trunk road and is now a .

The A127 was a and is now , this is particularly funny because I can exceed the speed limit in an 89hp car on a dual carriageway in 2nd gear.... This crazy limit is enforced by average speed cameras. There is less traffic about this year, so no doubt there will be less crashes because of this but it will all be down to the new cameras and lower limit. There does seem to be quite alot of skid marks on the road nowadays though. Panic braking anyone?
Oh and there was a big incident last weekend, involving the closing of the west bound carriageway, several fire engines and ambulances. Better get the limit even lower.

This wasn't my unrelated point - I had merely responded to your own point
Camera success is indeed measured in KSI reduction, but many other things cause KSI reduction, even at camera sites; hence so it follows that the standard measure for camera success, as you have quoted it, is an false one.
I believe this was the original intent of your contribution within this thread....so it's not so unrelated is it?


Would I be right to assume you agree that it is not in any way fair to give references to papers we don't have access to (without paying for it). Given this, can you please furnish with full texts or direct links?
Out of those 6 references, I could find only the 1 paper (Nilsson, G. (2004) Traffic safety dimensions and the power model to describe the effect of speed on safety. Bulletin 221, Lund Institute of Technology, Lund).This one is exactly as overly simplistic as I had expected.

Within it there is no mention of the effects of:
- tiredness or fatigue (which was one of my other points surrounding speed Vs crash involvement),
- displacement - the change of exposure with change of limit (pulling from/pushing to the road with the changed limit; the tests were done on selected roads, not the surrounding network)
- suitability of limit before the change (where travelling at the speed limit really would have been dangerous).
- variable limits, so displacing the exposure to safer (less congested) periods

Therefore, this analysis is again overly simplistic; there is no differentiation or compensation of any sort. This reference does indeed support your statement, but it fails my basic and simple scrutiny (unless you can counter it).


Sorry, are you saying you need credible evidence that 'going slower, for longer, (all else equal) will make the issue of fatigue worse' before you can accept the existence of it? Really?
I give this as a logically sound argument. There was no evidence to support RTTM prior to the Four Year Report, should that have prevented people (like us) from expressing that argument too?
This campaign doesn't have the resources to carry out such work - but the SCPs and/or the DfT do, and they should have done - so where is it?


There is no evidence, for or against; again I give this as a logically sound argument. What is there to regulate their activities if there is now less to stop them? Do you have reason to believe the joyriding/racer demographic has remained the same given that trafpol numbers (the only thing that can stop them) are declining?


My point was that the campaign isn't calling for something which is 'socially unacceptable and scientifically proven to be inefficacious'. By all means expand on your point so we can discuss this further.

Can you link to the campaign pages where policies which are 'socially unacceptable and scientifically proven to be inefficacious' are called for? I would like to see these.


No you haven't. Please show where you've shown speed cameras have been proven to have a positive impact when considering all the following factors:
- RTTM
- Bias on selection (non-camera-based safety features),
- long-term trends (non-local improvements),
- exposure ('push'ed displacement to safer roads),
- less overall travel (prohibitive fuel costs, credit crunch),
- concerted crackdown of other offences (e.g. driving while impaired)
If you manage this then you'll have succeeded where so many SCP PR staff have failed for the last ~9 years.
Unless you demonstrate that 'bias on selection' (for example) cannot be a confounding factor of speed camera effectiveness, your response is invalid.


I have never stated my understanding is at an advanced level; my point all along was that the claims of the effectiveness of the speed camera policy demonstrates a failure of understanding at even the basic level of those who make those claims.
We shouldn't be the experts here, but for us to show glaring errors on the part of SCP PR staff makes one wonder if, relatively speaking, we really are the experts.

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Views expressed are personal opinions and are not necessarily shared by the Safe Speed campaign

These days, speed limits are often changed at the whim of local residents. They no longer have anything to do with road safety but a group of locals' desire for a "quieter life".

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My views do not represent Safespeed but those of a driver who has driven for 39 yrs, in all conditions, at all times of the day & night on every type of road and covered well over a million miles, so knows a bit about what makes for safety on the road,what is really dangerous and needs to be observed when driving and quite frankly, the speedo is way down on my list of things to observe to negotiate Britain's roads safely, but I don't expect some fool who sits behind a desk all day to appreciate that.

Yes, I thought that Greenshed's quote was the funniest thing I had read all day as it's so obviously not true.

Just one example. In my local paper there were lots of letters from a wide group of correspondents (all definitely not "boy racers") all criticising a newly applied 30mph limit as being totally inappropriate for the road in question. One writer did mention that a local councillor lived on this road.

Limits set at inappropriately low levels just bring the law into disrepute.

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Malcolm W.
The views expressed in this post are personal opinions and do not represent the views of Safespeed.