Safe Speed Forums

That exact point came home to me last year when I went to Germany. I didn't speed because the limits were set at an appropriate level. I could actually just concentrate on my riding/driving like I haven't been able to in this country for years.

Greenshed - Maybe you think me or others here want a licence to speed? If so, you are very wrong. From what I've read, or where you have not replied, I think you may have a problem understanding what RTTM is so I've included this link from a pretty switched-on guy whom, IMO, comes from an impartial standpoint.

I actually agree with him that people generally neither understand nor care about RTTM, which is unfortunate because it's an essential part of understanding how skewed the DfT results are for KSI.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

The more I think about it the more I realise that what’s happening on the roads with speed is an extension of this whole paranoid H&S society.

I can eat that food when it’s within the time limit, but if it expired six hours ago I can’t.

I can drink up to 4 units of alcohol a day and I’ll be fine, but if I drink 5 units I’m a binge drinker on self-destruct.

I can go at 29mph because it’s within the speed limit, but if I’m doing 31 mph it’s dangerous and I’m going to kill someone.

Let’s just call it what it is; an unhealthy obsession with limits!


Well here’s the news: I do eat food which is sometimes days past its ‘best before’ date. I do have the odd day where I drink 5 units or more and I do sometimes exceed the speed limit where safe!

And you know what? I’m hurting no-one except in the minds of the obsessive and paranoid.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

I'll calm down in a minute

One of the main reasons I don’t believe the speed kills lie, (and I’ll bet the vast majority of people over a certain age will relate to this), is if I take a look at my own life and use empirical evidence. It pans out like this…

I started on the roads back in 1975. Between 1975 and ~1980 I had many accidents, (mostly small thank goodness), the frequency of which thinned out as I got older.

The last accident I was involved in was in 1984; not my fault but preventable by me if I’m honest. Jackanory - I was going around an island rather quickly on my motorbike when someone pulled out, (SMIDSY). Some will say speed nearly killed me but that would be wrong. I would say two things: Firstly, he shouldn’t have pulled out and secondly I was going too fast for the conditions. (I’ll repeat the salient part of that – For the conditions).

I still exceed the limit but I haven’t had an accident, or harmed anyone or anything, since 1984 and the great shame is some flatly refuse to see why. Is there a pro-camera poster here who can tell me why I haven't had an accident in 25 years please? (Long before speed cameras and obsessive speed enforcement).

The bigger shame is that these same people are in power and see only one, incorrect, answer while doing so little to address the bigger real problem. It’s an absolute disgrace and is costing lives every day!

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

Greenshed quoted some reference documents at page 3 of this thread

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

I am familiar with the works of Kloeden, McClean et al as they were done here in Australia and are often quoted by our Authorities. Indeed they were commisioned by agencies of the Australian (ie Federal) Department of Transport. For much of my professional life I worked for the Industry Department where I assessed applications for support of Industrial Research and Development projects. I covered the technology, methodology, commercialisation aspects, managerial capabilities and financial needs in an assessment. I never claimed to pick winners but only eliminated the unviable to give the others a better chance.

Professor McLean touted the results of the 1997 study as showing that exceeding the urban speed limit (60 kph) by 5 kph was as risky as driving drunk - clearly questionable. Not being in awe of Professors I read the full report and found that it was superficially convincing but had a number of critical flaws.

The researchers were provided with almost 1000 crash cases but only selected some 17% for study.
They then calculated the speed of the vehicles involved to a remarkable degree of accuracy using crash data and standard methodology.
They then went to the scene and, over a period of several days, measured the speed of the same type of vehicle under the same traffic conditions using radar. Sometimes there were as little as four comparison vehicles.
They then compared the speeds of the crash involved vehicles with the non-involved samples using regression analysis.
Their claim was that even very small increments of speed increased the crash probability and that this rose exponentially with speed.

Superficially convincing. HOWEVER

The selectivity of cases indicates a bias in selection. The criteria used in selection suggests a bias towards the type of crash where someone turns across the path of an oncoming vehicle or drives across its path on major roads.
Flaw one. Selectivity of cases

Adelaide, where the study was conducted, has many radial main roads which are not quite wide enough for two lanes in each direction. Its drivers are fairly poor by any standards and are prone to errors of judgement. The faster vehicle is that on the main road who is the "innocent" party.
Flaw two . No account of causative action.

The calculation of the speed of the crashed vehicles was taken as being very accurate. While I have not tested this I note that in all Court cases the calculated speed is quoted as a range. This is logical as the energy absoption of a crashed vehicle cannot be accurately measured.
Flaw three. Assumed accuracy of calculated speed

The speed of comparison vehicles was measured using radar.
Flaw four. Comparison of speeds measured by different methods introduces non-compensating errors.

It took several days of standing by the roadside to get the comparative speeds. Such obvious action causes speeds to be reduced as drivers notice the action - especially in a fairly small town.
Flaw five. The comparison speeds are distorted by driver reactions. (This is absolutely fatal to the study)

Regression analysis was carried out on the results. In my memory of statistics regression analysis is a useful tool in checking a trend line but in this case it is a demarcation line ie good event versus a bad event.
Flaw six. Use of inappropriate statistical methodology.

The rural study in 2001 was similarly flawed. They did try to reduce the chance of being seen while measuring the speed of vehicles by using a laser device at maximum range but South Australian country drivers make good use of headlight flashing to warn others hence the same fundamental flaw existed.

The re-analysis of the results of the first study (2002) was prompted by a review by Dr (now Professor) Ian Johnson of MUARC (Monash University Accident Research Centre) who only suggested that the results should be tested against the mean speed of vehicles not the seed limit. So much for "Peer review"

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The only thing that should be prohibited is prohibition.

I echo this myself. Started driving after passing test in 1974, not too much regard for speed limits on rural roads (which were 90% of what I ever drive on ...AND "allegedly" the most dangerous)...they were 70MPH then too. Had a few minor "offs" usually due to skidding on slippy surfaces and any bumps were usually people running into me...well below the speed limits too..

I still drive as fast , (when the conditions are right), as ever BUT I'm still here with no accidents so maybe "speed doesn't kill", maybe it doesn't cause accidents, maybe INEXPERIENCE causes accidents?

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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.

Regression the the mean does not explain away 100% of the potential effects of a treatment.

The idea is that if it's not taken into account the benefits of cameras to increase compliance can end up being overstated, but that doesn't mean there's not a benefit.

Big Tone, individual experience does not cut it I'm afraid, the system as a whole needs to be measured.

There's very little chance as a driver that you'll crash into something (although you can increase your chances by driving around quicker and quicker), but that doesn't mean this applies to all drivers.

And the system as a whole is a whole 'nother ballgame.

No, the stats show that it's younger drivers who are at most risk of having a fatal accident....they don't neccessarily go faster than us "old uns", so it must be another factor except speed that really kills.

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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.

Indeed. From the analysis I'm sure we all know and love: a base line reduction of 54% at urban camera sites was sectioned into:
- 35% for RTTM
- 09% for long-term trends (national level effects such as post crash response/care, safer impact protection)
- 10% for the 'scheme effect'
[table H7, Four Year Report]

That alone demonstrates the continuing deceptions of the SCPs with their still repeated claims of "40/50/60% reduction of KSI at camera sites" - but it gets far worse.

The 'scheme effect' is the genuine effect of treatment(s) applied to the site. However, what factors go into that 'scheme effect'?

- 'bias on selection' (police crackdowns and ANY other safety measures installed at the site; this is a real biggie, especially for urban sites as it could well account for significantly more than 10%),
- reduced exposure ('push'ed displacement to non-enforced roads; this may be small but still comparable to the remaining 10%),
- The camera (very possibly -x%, let alone 0%)


Given the above factors, it also doesn't mean there is a benefit at all - which has been my point from the start; in fact the scale of the other measures suggest cameras could actually be having a real negative effect (which is of course hidden by mixing them in with the other positive effects)!

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

Indeed.

I've never had a satisfactory answer from a speed-kills type about why there is a disparity between the average age of the people that are involved in KSI accidents, and those that arecaught by scameras. If speed kills is the be all and end all of road safety, those ages should be the same.

Indeed, IIRC the average age/profession/mileage of driver to get pinged by a camera also gets some of the lowest insurance premiums.

Is this across the entire road system, or just at camera sites?

The argument I've given was specifically relating to (urban) 'camera sites'.

The national picture is trickier to gauge, but the loss of the well-established fatality trend (resulting to the 'fatality gap') suggests something has gone very wrong here too. Coincidentally, the loss of trend began when the SCPs were first formed, and I don't know of any other policy shift over that period...


A question for you Weepej,

Do you agree that the effect of 'bias on selection' i.e. the addition of other safety measures within defined camera sites (as well as the effect of traffic displacement) can have a significant impact on the perceived effectiveness of the 'scheme effect' (the speed cameras) even when RTTM and long-term trends are accounted for i.e. even the 10% figure is optimistic, and that these other effects must be accounted for before anyone can reasonably make any firm quantative (numerical) or qualitive (simply positive) claim about the effectiveness of speed cameras?

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

I've not doubt it could, but we could come up with 100 other scenarios that could happen too, like just making a change without introducing speed enforcement could lead to some drivers removing any added safty margins with risk compensation (i.e. straightening out a bend, leading to higher speeds so when stuff goes wrong it goes even wronger).

And do you think a halving of accidents could be put down to these side effects alone on a section of motorway?

http://www.guardian.co.uk/uk/2006/apr/1 ... port.world

Thank you, but you've only partially answered my question.
Do you agree or disagree that these other effects must be accounted for before anyone can reasonably make any firm quantative (numerical) or qualitive (simply positive) claim about the effectiveness of speed cameras?



But there is less chance of the occurence in the first place - after all the roads with the least bends and highest speeds are somehow the safest of all (motorways) - do you agree?


Yup, absolutely. Referring you back to the RTTM factor within the Four Year Report:

(the KSI fall due to RTTM) / (The total KSI fall) = (35% drop /55% drop) = 65%

and that's for RTTM alone (and initial work by the same people suggests that the effect of RTTM is even stronger on non-urban roads).
I can't believe you missed that one. Have you not been keeping up with our arguments?

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

I am sorry, I have got to pick you up on this. This small village where I grew up in Dorset had a notorious bend on a road with a NSL. It was almost a nightly event that a car would come off the road and hit the trees, there were to my knowledge several fatal accidents every year at this one corner.

Now being that this was many years prior to the "speed kills" rubbish, the council re-engineered the corner and straightened it out. The result - much higher average speeds, amazingly it is still subject to NSL, And I can't say I have heard of a single accident at this location since the work was completed some 22 years ago!

Seems that this example that I know of rather contradicts your sweeping statement.

From what I can tell it is the 'when' they loose control and 'how' they loose control that changes, couple this with a frustration or inattention core fault and that 'set' can be very different than when an experienced driver when or how may loose control of have an event, in driving.

I do know of someone that is trying to have a survey done in many areas with and without cameras but of similar road 'qualities', which will be most interesting when this happens ...

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Safe Speed for Intelligent Road Safety through proper research, experience & guidance.

You see to me that's a clear case of speed kills. People were clearly approaching the corner too fast if thye managed to fall off the road negotiating it.

In that case they've no-one to blame but themselves IMO.

In a way you are right, however, this example clearly shows (in my opinion anyway) that requlation of speed is not the ultimate answer. This was a clear example of poor road design, remove this element and the speed becomes irrelevant. Had the speed limit been reduced to 30, I suspect that cars would still be falling off the road to this day.

{edit to add]
This has always been my contention, it is safer to not have a crash at 70 than to have a crash at 20.

Where I used to live there was a corner, not far away, on a rural NSL which even at 30 MPH in the dry would have been fast for the corner, 20MPH was probably the speed most would take it even in the dry. It is a 90degree right on a narrow road just wide enough for two cars and a bit of a negative camber and straight on means you go off into the trees.

Every year, at least two cars would go off into the trees. I don't think anyone was ever killed through it and the road is just the same now BUT the point is....how do you stop accidents here using speed restrictions/cameras etc?

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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.

I have some sympathy with you there but still think the point has been missed.

What it suggests to me is that those drivers killed were reckless or irresponsible and the road improvements mean others like them will simply continue to be reckless and irresponsible somewhere else. The KSI has simply been moved but because it's not happening there anymore it looks like a cure.

Surely what is needed is better training so that drivers do not crash in the first place. If I see a bend I’m not sure of or have any doubt about the conditions I slow down. They obviously didn’t and paid the ultimate price sadly.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.