Safe Speed Forums

The irony!

- Not all camera sites need to be set up such that bias-on-selection would be a significant factor.
- Not all camera sites need to be set up such that RTTM would be a factor.
Yet for some reason they are – it’s not us bringing in other factors and causing confusion, the powers that be are doing it.

Of course there are ways to find out, as any half decent statistician will tell you:
- Disregard the random spate and compare the long-term before and after
- Site cameras randomly (do not place at temporal hotspots)
- Use Empirical Bayes methods

These are obvious methods to use to account for RTTM (bias on selection is a little more tricky as the benefits of all other types of safety measures have never been quantified – conveniently odd if you think about it), yet the SCPs et al with all their resource simply choose to ignore these and just state “blah blah at camera sites”.


Wrong. People can speed at camera sites and still do, obviously you’ve not been considering my posts properly. And yes it does matter how the accident rate went down; if a method is successful then it should be rolled out, if not then it must be ended such that the resource can be allocated elsewhere which could yield real benefit.


What? Are you saying the road just suddenly became more dangerous? Either it was a random blip, even an impulse, or the camera was causing a danger, either way the camera was certainly ineffective – completely at odds with the previous quote. You can’t have it both ways.


A case of bias on selection – by your own admission. RTTM cannot be discounted too.


This is not playing with numbers. The interpretation is pure and simple; there are no two ways around it.
- There are not enough accidents where speed cameras could have made any difference (the damming DfT analysis).
- The phenomenon of RTTM is now widely understood and accepted.
The resulting conclusion is inevitable.

It occurs to me that you don’t really understand the phenomenon of RTTM, or at least you are not going to acknowledge it – even though the DfT has!

It further occurs to me that you know you cannot counter my argument based on the simple science and hard data (it was you who asked for the evidence, which I happily gave); instead you reply with woolly ‘yeah but no but maybe’ type responses, completely disregarding what is so logical. It must be impossible for the unbiased reader to consider you to be truly open-minded when you cannot accept what is so unpatently obvious, so I believe I’ve done enough here.
No doubt you’re going to have the last word but I doubt it will matter as it’s now clear you are not posting in good faith.

And especially a properly constructed randomised trial where half the sites are randomly selected for 'treatment'.

Imagine the outcry if untested drugs were force fed to healthy patients - but that's exactly what we have done with speed cameras.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Forgive me for not being totally up on the relevant language. So are you saying that when cameras are installed, other measures are put in place, or at that particular site there are also other factors that you could accredit with a reduction in accidents?

No. There are no ways to prove it. There are ways to formulate statistics based on theories, but you end up coming down to odds and percentages. Which are very useful for clouding the argument.



That's an interesting conclusion. Does speeding (above the limit) not reduce at camera sites then? Either people are panic braking or they aren't. You can't claim both sides of the argument.



No. You can see what I said quite clearly. You understand that averages are just that don't you? Of course you do, because you are using it in your argument. Just because there were 2 KSIs one year, doesn't mean that there will be 2 the next. There are lots of factors involved, which is exactly the point. Sometimes blips happen, sometimes traffic flow changes. Two examples from many. In this situation, like I clearly said, one camera has been placed at one point along a 1-mile stretch of narrow, sometimes heavilt congested and sometimes fast, road. The figures are taken from the whole length.

You don't understand this one thing or the other issue do you? It's very basic, and might help your understading. Things change, there are several factors, the reason cold be one, none, several or all. Any combination. It's really very simple to understand. Unless you want to cloud the argument. By choosing two options as you have in this instance, ignored the rest, and then deciding on the one that you like. That's not good arguing.



Dear me. I'm not saying anything can be discounted. Again, you choose whichever factors you wish to ignore, to suit your argument. In this way you can try to discount the effectiveness of the camera. You can try, but you can't prove it. Especially if you don't consider all the factors. It could be bias on selection, it could be RTTM, it could be other things, it could be a combination, it could be none. It is naive to decide, as you do, that it is down to one factor, and discount the rest. You are allowed to make concessions without losing an argument. In fact, making concessions put weith behind you.



Ha ha ha. I understand data. You don't. You think that 'hard data' means that you can then draw definite conclusions from the statistics. You can't. Which is easy to prove, as to prove your argument you use the 'raw data' to draw your own irrefutable conclusions. the other side uses 'hard data' and suddenly it is ok to claim that other factors aren't being considered, and that the hard data doesn't prove the conclusions that your opponent is correct.

I have never disounted RTTM.

If you take away all the stats and data, all you are left with is the old "I'm right, because of this and this, and will ignore anything else you suggest that needs consideration. You are wrong because you don't consider what I am suggesting."

Any discussion involving facts needs to start at the very basic understanding that you are only ever talking about probabilities. You seem to be able to grasp this with your opponents argument, but won't accept it for your own. Pretty poor really.

BTW if you get no response today, it is not because I have condeded defeat. I'm going to give up at some point, because this isn't getting us anywhere, and there are some blinkers involved in your part. I have no agenda at all. You do, and it would do you good to remember that.

No, I'm off doing more interesting things that being a nerd on a forum. I'll leave the nerd hat hanging up for later.

You've just shot yourself in the foot big time

No need to say anymore

Which is EXACTLY what the government and SCPs are doing. The problem is, they've got the media on side to regurgitate the argument to the masses who on the most part aren't intelligent enough to understand the argument and so swallow it without question.

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Science won over religion when they started installing lightning rods on churches.

Jub Jub it is incredibly simple, if there are 3 serious accidents on a section of road that previously hadn't had any then unless the road design or usage has changed then it is a Chance occurrence. This is especially relevant as in a lot of locations where it was a freak accident that caused the camera to be erected then drivers will brake then accelerate to get through the camera without triggering it, i know several sections of road around here that are safe for unrestricted but are limited to i know they are safe at 70 as the limit was changed during the time i have been driving the road.

RTTM does exist as even before speed cameras you didn't have sections of "safe road" that had series of accidents, as if it had a series of accidents then the road design and construction was checked to ensure it wasn't the cause. RTTM is also exhibited in any other "freak" occurrence,

Well we got there in the end. It started off reasonably, and is descending into name calling. I knew that would happen tbh.

Not quite sure what this thread's about anymore - but recent posts seem to be the speed camera argument. I would present the following argument :

- I think speed cameras are dangerous, because they divert my attention (no proof though)

- I know speed cameras don't work because:
- They don't make drivers slow down (proof is the number of tickets issued). If they don't make drivers slow down then whatever your view they cannot possibly prevent accidents.
- Hospital stats show no reduction in KSI figures (proof is the BMI report)
- Breaking the speed limit is only a minor cause of accidents (proof the DfT contributory report)

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Wake me up when the revolution starts
STOP the Toll Tax http://www.traveltax.org.uk

-well done. You are capable of more than some posters on this thread. You think that you know. They know that they know.
-Mmmm. Ticket issuing is not a real indicator, so you can't really use it as evidence. It doesn't show speeds prior to the installation, and it also cannot predict whether the driver would have been going faster without the camera there. The only way of showing a change is long-term speed checks before and after. So this does not prove that they prevent accidents.
-Camera installation is only one factor to consider when processing hospital stats. As we all know, there are many more factors.
-Increase speed=increased chance of injury. As stated (but not proved) in the DfT report.


Look, we could go on at this all day. The simple facts remain.

SafeSpeed is actually able to prove very little. It can make proposals based on consideration of all of the issues, but it can't prove anything. And that needs to be accepted. You can put a case forward questioning their effectiveness, but you cannot prove they are ineffective. Stating that they are places you on very dangerous ground, because then the onus is on you to prove without doubt that your statement is correct, and you cannot.

For example, you say that speed cameras do not slow people down. This again is unproven. Realistically, you can only suggest that they slow some people down but not others.

The other problem that you have with this campaign is that it is born out of self-interest. This is evidenced by the promotion of methods to evade detection when driving over the limit, and so is clearly not about improving road safety. Of course, people can change, but no statement has been made to create any distance between these actions. Passing their discussion off as mud-slinging merely puts Safespeed in a worse position.

There is nothing more really to be said. Because there is no black or white. I think Jeremy Clarkson put it best when he said-

The inescapable conclusion to all this is that if you have all the facts to hand, you will see that there are two sides to every argument and that both sides are right. So, you can only have an opinion if you do not have all the facts to hand.

Lets imagine that Safe Speed can't proove that cameras don't work.

The government cannot prove that they do.

I live my life in my own sweet way when all of a sudden the government impose something on me that inpinges on my life, my freedom and my livelihood. All of this based on something they can't prove. The state should not impose upon my life unless they have a sound reason to do so.

In my opinion the first step is to show that the government can't demonstrate their effectiveness,

the second step is to provide proof of their ineffectiveness.

The third is to prove that they are actually worse than ineffective.

That is probably the most sensible post I have seen on this thread. Of course, I would question the highlighted section.

Of course, it then leads to all the arguments about how you show and prove these things. And the circle continues...

A very reasonable reply - and I can understand what you're saying, however:

- at the end of the day, it's not speed that matters, it's accidents

Hypothetically, if everyone drove at 200mph and there were NIL accidents, then we (including DfT) should be very happy. Conversly if we all drove at 20mph and accidents doubled, then we should all be very worried.

So it's not about what we describe as "technical" offences (where all is ok at 70mph, but we're criminals at 70.5mph). It's about the results in terms of safety.



I merely used the number of tickets issued to show that the stated purpose of cameras (to stop speeding) does not work, as evidenced by year on year increases.

Again regarding hospital stats, I am not trying to link them to cameras, just using it to show that accidents have not decreased since the explosion in camera use (despite the grossly misused and misleading "42%" reduction in accidents)

What should be without doubt is that even the goverment say that breaking the speed limit is responsible for less than 5% of accidents - so why the importance placed on cameras as more or less the only way of improving road safety? The DfT are failing dismally to improve safety. But you'll notice a servere lack of comment from them regarding either the contributory figures or the hospital stats.

If you read through this site, you'll see that very little is actually about speed cameras. It's all about having safer roads. Yes a lot of us object very strongly to being criminalised for grounds that (according to the stats above) have very little to do with road safety.

My comments on cameras being dangerous are personal ones. As I said I have no proof - but I do know for certain that I cannot concentrate as much as I normally can when surrounded by cameras & feel a lot less safe.

_________________
Wake me up when the revolution starts
STOP the Toll Tax http://www.traveltax.org.uk

Don't be silly. Where's the self interest? I've never worked so hard nor earned so little in my life. Actually running the campaign is truly altruistic. There is literally nothing in it that I want for myself.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

What is the evidence to back up the claim of self interest?

Look what I just found... Jub Jub's assessment of us:

http://www.cyclingplus.co.uk/forum/topi ... ichpage=18

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Actually, I think that one of the papers that was co-authored by Linda Mountain indicated that traffic does slow down at camera sites - but only for about 50 yards. As it appears that cameras in general are not sited at the actual "danger spots" but are positioned in places that are safer / easier to service / more visible / more profitable (take your pick) it is reasonable to suggest that therefore the camera may not make any appreciable difference to the traffic speed at the point of most danger.


Sorry? "Promotion of methods to evade detection"?? I've been a member of this group for a couple of years now and read it for some while before that and I have no recollection of anything like that.


Yet most of the members on this forum bang on incessantly about safety... Surely sirrah, you jest?


One of us is in an alternative universe - and I don't think it's me.


Clarkson is a very capable and provocative journalist, he certainly isn't a statistician. The efficacy or otherwise of speed cameras can only be quantified in statistical terms.

Simple empiricism would cast severe doubt upon the claims made by the "pro-camera" lobby... Millions of convictions every year yet KSIs are not falling. Durham, the only English county without speed cameras has the best road safety stats... The DfT's own studies now show that "speeding" is a very minor contributor to accident causation yet the vast majority of effort in "road safety" is concentrated upon speed - it's the classic case of "making important that which you can measure, not measuring that which is important". The "law of unintended consequences" has validated the practice of cloning, running unregistered (and therefore probably uninsured) cars as an effective way of avoiding prosecution. SafeSpeed is calling for a return to higher levels of "traditional" road policing - which *can* do something about this, as well as bringing some sanity back to the enforcement of traffic laws.

Cameras can appear to be very effective - here's a snippet from my local paper showing exactly how much so...


Pretty good eh? Better than 75% reduction in accidents at that site. It was, in fact, the best reduction figure for all of Shropshire that year.

However... I've been a bit sneaky, that's actually only the second part of the story... Here's the first part:


(My bold). So... Shropshire's most successful "camera", sited at the "most dangerous" place in the county wasn't ever installed. The entire "effect" was purely RTTM. But By God, to the uncritical / innumerate (ie average journalist or government minister) it looks good!!

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"Politicians are the same the world over... We build bridges where there aren't any rivers." - Nikita Kruschev

So the SCP publicised the fact that a stretch of road 'fixed itself' without the need for camera enforcement and the journalists/public were to stupid to pick it up????

They are claiming 42% reduction at camera sites but here we are with a 75% reduction by natural means.

It's witchcraft I tell you!

I'm not about to rubbish Jub Jub's conclusions because some of his conclusions are, IMHO, not entirely unfair.

I do have an issue with being rolled into his Point 6 however.

On the subject of proof - no Safespeed cannot categorically prove speed cameras don't work.

On a petition thread in the Campaigning section I myself have criticised a Safespeed endorsed wording stating that speed cameras were responsible for thousands of deaths. I myself stated more than once on that thread that Safespeed cannot prove that and thus it was damaging to Safespeed's credibility. So far no-one has seemed interested in discussing this with me on that thread.

The above cut from C+ illustrates beautifully the results of making claims which are not defensible.

Safespeed, arguements about RTTM etc can only prove that the SCP's facts are false. Disproving one arguement does not prove another.

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