The following is pasted with due acknowledgement to the ABD. Original is at www.abd.org.uk/ - follow the "speed limits" link on the left, then "Does a 1mph reduction in speed really reduce accidents by 5%?" in the main body.
Note their main point, i.e. that going back to the source shows that the authors themselves apparently warned that their results had statistical shortcomings.
Does a 1mph reduction in speed
really reduce accidents by 5%?
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A key phrase in the anti speed campaigner's handbook that appears again and again is
?A 1mph change in average speed causes a 5% change in accidents?
It is quoted ad nauseam is most Government anti speed publications. Now to any reasonable human being who knows anything about driving, this statement is clearly absurd, yet it alone is used to justify many of the obstructive and oppressive measures being taken against safe drivers. An ABD examination of it's origins and a demolition of the arguments used to justify it is therefore long overdue.
It originates from a study published in 1994 by the Transport Research Laboratory called "Speed, Speed Limits and Accidents" (ref S211G/RB). This document contained no new research, but simply correlates the results of previous studies around the world, which were all involved with measuring the effect of a change in the posted speed limit.
Examples are quoted of accident reductions following the introduction of reduced speed limits going back to the 30mph built up limit introduced in the UK in 1935, and on the effect on average speeds of speed limit changes.
However, the only examples of changes in accidents and mean speeds being compared at the same time are:
Effects of temporary speed limits on Finnish motorways 1962-1976. All accidents.
Temporary decrease in Swedish Motorway and Dual carriageway limits, 1989. Injury accidents.
Danish built up area reduction in limit from 37mph to 31mph. All accidents.
Introduction of 19mph zones in Hamburg, 1985. Injury accidents
Swiss speed limit reductions on motorways and rural roads, 1985. All accidents.
Increase in accidents following increase in US limits from 55 to 65mph. Fatal accidents only.
A simple graph follows where the change in 'before and after' mean speeds in these six examples is plotted against the percentage change in accidents from one period to the next. A line is then drawn through the points which corresponds to a 5% change in accidents per mile an hour change in mean speeds. Thus the offending sentence is born.
ANALYSIS
This argument is so full of holes it is hard to know where to begin attacking it. To be fair to the authors of the report, they make many of these points themselves, but, inevitably, these are lost when the politicians are looking for a simplistic solution to a complex and poorly researched problem. They begin by making four fundamental statistical errors which any A-level student should be familiar with.
Is there a scientific causal link to back up the apparent statistical relationship?
It is incorrect to assume causality from a statistical relationship. To illustrate this, take the assertion that wearing a baseball cap backwards is linked to a 20 point reduction in the IQ score of the wearer. A plausible statistical link. It would be obviously ridiculous to suggest that educational standards could be increased at a stroke by banning baseball caps unless it could be proven that the cap was the cause of the low intelligence rather than simply a symptom. If the ban went ahead anyway, the real causes of low achievement in school would be ignored and some rather more intelligent people would get sunstroke due being forced to venture into the midday desert sun hatless. A ludicrous scenario? It is not far from what has been done to the motorist here!
Is the sample representative?
It has been assumed that because a graph neatly fits these six examples then the same must be true of all roads. To be valid, a survey must be chosen at random from a representative section of the population. The six studies are all related to speed limit changes which had been imposed for some purpose other than the research, and so most certainly do not come into this category.
Are the same things being measured?
Since three studies refer to total accidents, two to injury accidents only and one just to fatal accidents, how they can be justifiably plotted on the same graph is beyond comprehension. Also, they relate to different road types ? how can what happens in residential Hamburg in 1985 have anything to do with Finnish motorways in 1962? Add to this a myriad of different measurement techniques and other factors and you have an appalling mishmash which says nothing of value.
Is the result consistent with trends in the general population?
Any survey has to be questioned if it comes up with results that are inconsistent with trends observed in the whole population. These trends show a steady fall in accident rates and casualty rates throughout this century despite huge increases in free flowing traffic speeds. More specifically, injury accident rates fell by 30% in the UK during the 1980s whilst road speeds increased.
If the violation of general statistical rules such as these are not enough, some of the specific logical errors in this study damn it even more comprehensively.
The Irrelevance of using Average Speeds
Injury accidents only happen once for every 1.8 million kilometers driven in the UK. This makes them, at worst, a once in a lifetime experience even a high mileage motorist. An accident results from an exceptional combination of circumstances, and certain demographic groups, locations and conditions drastically effect accident rates. What relevance can average speed of the whole vehicle population have to such rare events?
They do not say how the average speed is measured. Almost certainly it will be done at certain specific points on the road by laying two temporary sensor tapes across the road. Since no road, even a motorway, has an identical spread of hazards along its entire length then a valid test of speed changes vs accidents can only be made within a very short distance of the test sensors themselves and not on the entire road. The number of accidents at these points will almost certainly be statistically insignificant. Moreover, the hazard distribution will vary along the road with traffic and weather changes, resisting any attempt to even this out. To illustrate this, take a country road made up of straights and bends which can only be taken at 40mph in the wet. Most accidents will happen on the bends at night in wet weather and speeds on the straights in good conditions will be irrelevant.
The Pitfalls of using Changes in Accidents
Quoting the percentage change in accidents makes no sense unless it is related to the absolute accident rate. Take the Spanish Motorway death rate of 61 perBnVkm against the Dutch 3.2 per BnVkm. These motorways all have the same 120kph limit! It is not hard to imagine similar measures resulting in a fall in deaths in Spain but a rise in Holland because of totally different accident causation mechanisms.
The locations for many of the tests could have been chosen because of either a statistical blip (admitted in the Swedish study) or a genuinely high accident rate on those particular roads. In the former case the accidents could have fallen anyway, in the latter a reduction in limits may well have been necessary for genuine safety limits. Generalised conclusions cannot be drawn without absolute statistics.
The Insanity of Combining the Two
If this 1mph 5% law was true, the average speed on the Spanish motorways would have to be 60mph faster than that in Holland, and the West Germans with would have had to be travelling slower on their largely unlimited Autobahns than the Americans were when their freeways were limited to 55mph. Hmmm!
CONCLUSION
All of this illustrates that macro statistical techniques have been inappropriately used on subject matter where it is impossible to isolate variables and where the incidents in question are both rare and subject to complex causal factors. The conclusion of the TRL report is therefore as statistically invalid as it is rationally absurd
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And from Paul Smith at www.safespeed.org.uk:
www.safespeed.org.uk/trl421.html
As ever, he is less emotive than ABD and a little more analytical.
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And from Paul Smith at www.safespeed.org.uk: www.safespeed.org.uk/trl421.html As ever, he is less emotive than ABD and a little more analytical.
The safespeed critique descends rapidly into comedy: "It's well know that UK motorways are our safest roads. TRL511 immediately goes one stage further and the very first finding is that the frequency of accidents is lower on faster roads."
Of course it does -- the fastest roads are those such as A-roads and motorways designed for fast speeds. Motorways would be much safer than residential streets if both had the same speed limits, because the motorways have features like clear line of sight and grade-separated junctions which make them inherently safer. But that's a wholly separate question to the one addressed by the studies, which is what happens to the accident rate on any particular road when speeds are reduced.
The rest of both the ABD and the Safespeed ripostes are a bit silly.
The studies referred to are not exactly amateur observations: they are done by professional statisticians. The methodologies used are subject to pretty wide peer review, and if they were as flaky as suggested there would be an army of statisticians attacking the integrity of govt statistics. However, neither the ABD nor Safespeed can find any professional statisticians to mount such a critique.
Both ABD and Safespeed attack the studies because they fail to provide a conclusive proof of causality, which is not what the studies set out to achieve -- they were quantitative studies which examined a statistical correlation, not qualitiative studies. (It is notoriously dificult to conduct qualitative studies on a large scale, and the police reports cited are a pretty poor riposte -- to be meaningful, there would need to be some clear, consistent and verified methodology in assessing the causes)
Those studies used a fairly simple statistical technique: change one input variable (speed), and see what happens. The result across all these studies has been consistent: lower speeds means fewer accidents. The critics cannot cite a single study which demonstrates any other outcome -- all they do is to cry "unfair" at the overwhelming mass of evidence.
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Some people would really only be happy at the return of the man with the red flag.
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Unbiased and genuine question:
In Britain, over the last 25 years say, and normalised for per vehicle and per mile, and for all types of road,
has the average speed gone up, or down?
and has the 'number of accidents' (info from insurance claims, or police attendances?) gone up, or down ?
I don't have the figures - anybody know what they are?
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Unbiased and genuine question: In Britain, over the last 25 years say, and normalised for per vehicle and per mile, and for all types of road, has the average speed gone up, or down? and has the 'number of accidents' (info from insurance claims, or police attendances?) gone up, or down ? I don't have the figures - anybody know what they are?
I dunno the figures, but I doubt they would tell you much, because so many other factors are involved, such as: congestion levels; effectiveness of cars braking and handling systems; changes in road design, construction and maintenance; differences in driver training.
All those factors have an effect on safety, and it wouldn't make sense to use data based on all those changes and draw conclusions about one factor in isolation. The usefulness of the studies on speed is that they do isolate just the one factor.
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so many other factors are involved, such as: congestion levels; effectiveness of cars braking and handling systems; changes in road design, construction and maintenance; differences in driver training. All those factors have an effect on safety,
A positive effect for all of them, I think, including congestion. Try having a fatal accident in a traffic jam (on second thoughts, don't, actually).
I recall that speeds generally have fallen, but I can't cite evidence for that and don't offer it as gospel.
Why, then, have the fatality rates not dropped? Perhaps we are getting something wrong?
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Recent government statitistics have shown that excess speed is a primary causal factor for around 5% of accidents. I also noticed on another study from a university that 5% of drivers were causing 45% of accidents and they reckoned that 17% of them were causing *all* accidents within their study group. The other 83% weren't at fault. As speed related accidents aren't responsible for 95% of crashes then if we lower average speed by 1mph will that not wipe them all out? It should if the theory is correct. Or I've got the wrong end of the piano?!
But as the vast majority of accidents are caused by a minority of drivers wouldn't we have more success going for those near 100% causes of accidents rather than the 5% cause? Bet your life those 17% are mostly made up of the untaxed, uninsured and maureen driving school types!
teabelly
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"It's well know that UK motorways are our safest roads...
Isn't this arrived at from the ratio of accidents to miles covered? This would make motorways appear safer simply because people use them for longer journeys. It's not just that other types of road have more hazards. This would be the method that makes air travel seem to be the safest form of transport (I'm not denying that it is).
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Come come No Wheels.
We start with:
"There are often claims here that speed doesn't cause accidents etc, so I thought it might be useful to point Backroomers to a coherent summary of the research."
On being alerted to the lack of any proof of causality in that evidence, we have:
"Both ABD and Safespeed attack the studies because they fail to provide a conclusive proof of causality, which is not what the studies set out to achieve -- they were quantitative studies which examined a statistical correlation, not qualitiative studies."
But you cited the studies to disprove a lack of causality. Moving goalposts?
You cite the lack of counter-evidence from professional statisticians. But they will not object to the papers, because the authors acknowledge the difficulty of reaching a conclusion based on their research. However, that bit doesn't get reported - only the simplistic headline.
I agree entirely that an otherwise identical accident will be worse if the speeds involved are higher. I also agree that a higher speed can make an accident more likely, and that a lower speed can make an accident less likely. However, I don't agree that a higher speed will make an accident more likely, nor do I agree that a lower speed will make an accident less likely.
I just think it's a little more complex, and am disappointed when it's presented as simple. It leads to the wrong driving mentality - www.honestjohn.co.uk/forum/post/index.htm?m=223699...e
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We start with: "There are often claims here that speed doesn't cause accidents etc, so I thought it might be useful to point Backroomers to a coherent summary of the research." On being alerted to the lack of any proof of causality in that evidence, we have: "Both ABD and Safespeed attack the studies because they fail to provide a conclusive proof of causality, which is not what the studies set out to achieve -- they were quantitative studies which examined a statistical correlation, not qualitiative studies." But you cited the studies to disprove a lack of causality. Moving goalposts?
Not moving them at all: you miss the word "conclusive".
Statistical studies cannot (by their vey nature) demonstrate exactly how it is that lowered speeds leads to reduced accident levels, which is the ABD and Safespeed's complaint.
By isolating speed as a factor, the statistics demonstrate very clearly that lower speeds leads to fewer accidents. Despite this overwhelming evidence, the speeding lobby continues to argue that we should avoid taking any steps to reduce speeds (and therefore accidents) until we can show exactly how it works.
So ... we know from countless studies all around the world that a simple measure will save lives, but the ABD and the rest of the speed merchants don't want us to use it because there isn't yet conclusive data on exactly how it saves lives? (There's plenty of evidence about the linkage, but the complaint is that it isn't conclusive).
Thank goodness the politicians are unimpressed by that sort of logic. A good summary of a cross-party assesment of the arguments can be found in the 2002 report of the House of Commons Select Committee on Transport, Local Government and the Regions on Road Traffic Speed -- see the section on "The consequences of speed" at www.publications.parliament.uk/pa/cm200102/cmselec...m
It's also worth reading the testimony of two senior transport academics, at www.publications.parliament.uk/pa/cm200102/cmselec...m
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NoWheels,
Please don't class me as a "speed merchant". I suspect that the ABD would also object, and Paul Smith makes the point as well. I may drive a BMW and a Porsche (not at the same time..) but I have two small children and object strongly to unsafe driving. I fail however to automatically equate "fast" with "unsafe" in all circumstances.
In fact, about 40-50% of the time I find myself going distinctly slower that those around me would evidently wish to travel. I do not hold myself up as a shining example (for very good and painful reasons) but I see in many other drivers an inability to match speed to conditions, in both senses.
Again, all we see is the citation of "speed=accident" to justify lower speeds per se. The research may be careful and well presented but its use by politicians and civil servants is not so careful. The undoubted fact that innapropriate speed is dangerous is used to justify lower speeds and to punish speeding, but these three concepts are only loosely related and are not synonyms.
I did acknowledge the extent to which I see a link between speed and safety; the evidence cited does not take us beyond that point, IMHO. And 1mph=5% is frankly so simplistic as to be insulting.
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Please don't class me as a "speed merchant". I suspect that the ABD would also object, and Paul Smith makes the point as well.
Patently, I know that PS and the ABD object, but you only have to burrow a bit to see why the objections should be taken with a pinch of salt. PS's website makes his real position clear: he is against speed limit enforcement, despite his claims on the front page.
Try this claim, amongst others: "Responsibility for safe speed setting is being removed from drivers. Instead they must drive to standard speeds posted by local authorities and others" (see www.safespeed.org.uk/effects.html )
That's why I mean by speed merchant: the drivers who refuse to accept the right of the law to impose (and enforce) a maximum speed, as well as those who drive too fast for the cicumstances. Speed limits are nothing new: his claim about responsibility "being removed" can only be a reference to the increasing effectiveness of enforcement.
Plus, of course, his bizarre idea that drivers are being asked to follow "standard speeds". He doesn't seem to grasp the simply point that a speed limit is a maximum, not a standard.
I think we agree that it's often appropriate to drive well below the limit, but the law doesn't prevent that -- on the contarry, it encourages it.
I fail however to automatically equate "fast" with "unsafe" in all circumstances.
I don't see anyone arguing that fast is unsafe in all circumstances, and it's a bit naughty to suggest that. The point which I and others make is that in any given set of conditions, faster is less safe.
That's why speed limits are set, and why there are different limits on different roads. The evidence is very clear that, for example, a high speed is much safer on a motorway than a lower speed on an urban road.
That may be an argument for building more motorways; it's not an argument for saying that any given speed limit shpuld be increased.
In fact, about 40-50% of the time I find myself going distinctly slower that those around me would evidently wish to travel. I do not hold myself up as a shining example (for very good and painful reasons) but I see in many other drivers an inability to match speed to conditions, in both senses.
That sounds like very responsible driving.
Again, all we see is the citation of "speed=accident" to justify lower speeds per se. The research may be careful and well presented but its use by politicians and civil servants is not so careful.
Before accusing the politicins of carelessness on this one, look evidence from the transport academics presented to the commons select committee. They are clearly urging efforts to reduce speeds, which is what the politicians are doing.
The undoubted fact that innapropriate speed is dangerous is used to justify lower speeds and to punish speeding, but these three concepts are only loosely related and are not synonyms.
Yes, the enforcement techniques we have so far are a bit crude. But there given the clear evidence about the effects of speed, restraining speed is one very useful tool in a package of road safety measures. (Restraining speed has many other social benefits as well, but that's a separate point)
Current technologies (particularly cameras) make it remarkably cheap to enforce speed limits, with very clear benefits to the accident rates. Those cameras save lives wherever they are installed.
Sure, there are plenty of other important matters of road safety which ought be enforced too. But wanting better policing of other road safety issues is no reason to object to the use of one method which works very well.
I did acknowledge the extent to which I see a link between speed and safety; the evidence cited does not take us beyond that point, IMHO. And 1mph=5% is frankly so simplistic as to be insulting.
Of course it's simplistic: it's a headline summary, desighned to encourage people to look behind it. The figures vary in different situations, as you can see from the breakdown which the SSI itself presents. The are further speed-related factors, such as speeed differentials, but they all point to stricter enforcement of limits.
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NoWheels,
Apologies for missing your reply. I think I lost it in the SSI stuff.
Thank you for your compliment, btw.
I can't speak for Smith or the ABD, of course, but I think Smith's position is a little more complex than you point out. His argument seems to be more along the lines that limits should be correctly set - he cites the 85th percentile research, which apparently shows that the safest speed at which to travel is the speed at which, in the absence of any limits, 85% of drivers would be slower and 15% faster.
He then points to the DoT requirements for cameras and shows that, in effect, they place cameras where the limit is well below the 85th &ile level. Thus they will catch drivers who are driving at the safest speeds.
So he is not against speed limits as such, merely against the vigorous enforcement of the wrongly set limits. His problem is that it can't be summarised in a soundbite so requires the listener to be attentive, have a reasonable grasp of statistics, and be willing to wade through the interminable and rambling line of argument that is his "house style".
My profile mentions that I am concerned that easy to enforce laws like speed limits are being enforced, instead of other laws that are more subjective but have a greater correlation to safety. I can well see why; you are either above 30mph or below, so a prosecution is usually straightforward. Nevertheless, the aim of road traffic law is to achieve safety not a specific speed (as such). My worry is that we are moving towards a focus on easy enforcement in the name of "efficiency" but are moving away from the prevention of unsafe driving per se.
My accident record is not perfect; sometimes my fault, sometimes not. None of my accidents took place above the speed limit. None of them caused injury (thank heavens) but several could have - one involving an unsafe load came within 18 inches of orphaning my 2 week old daughter. That kind of thing affects your attitude. I tried all the relevant authorities but none were interested in my report of the local skip operator, who was routinely failing to cover loads as is (I understand) legally required.
Meanwhile, I did not feel at all endangered by the police vehicle travelling at 90mph on the M40 twice last week (see previous posts). I did feel endangered when he tried to pull out right in front of me. Only one of those offences is usually enforced, and it isn't the dangerous one.
As I said to SR in similar circumstances, I think we agree on a lot more than might appear to be the case. But I hope this clarifies where I'm coming from and where I think the UK is going.
I'm going to end by disagreeing with two things you've said, though;
Current technologies (particularly cameras) make it remarkably cheap to enforce speed limits, with very clear benefits to the accident rates. Those cameras save lives wherever they are installed.
As I understand, our fatality rate is now static after decades of decline. So I don't see any clear benefit. Nor do I see how the lives saved can be attributed to the cameras when other major changes are usually made at the same time.
Of course it's simplistic: it's a headline summary, desighned to encourage people to look behind it.
Except that they don't, in my experience.
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"The studies referred to are not exactly amateur observations: they are done by professional statisticians. The methodologies used are subject to pretty wide peer review, and if they were as flaky as suggested there would be an army of statisticians attacking the integrity of govt statistics. However, neither the ABD nor Safespeed can find any professional statisticians to mount such a critique."
Whilst I tend to believe that TRL's output is as objective as it gets, the problem is how that output is used and interpreted.
On the other hand re the last sentence quoted, for as long as I can remember Paul Smith has had the challenge posted on his website for anyone to come along and prove his assertions are wrong. Afaik no-one has.
My problem is being able to see both sides of the argument.
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What is really needed is large scale before and after figures for incidences of traffic accidents when the speed limit is altered. Western Australia changed its speed limits for the majority of residential urban streets from 60kmh to 50kmh on 1st December 2001. At the time they claimed that:
" It is anticipated that a default speed limit of 50km/h in built-up areas will result in a 33% reduction of speed-related crashes resulting in injury.
McLean, J., Kloeden, C., Anderson,. R. (1999) Speed and the Risk of Crash Involvement. University of Adelaide, South Australia." Quoted from Office of Road Safety website.
They are intending to do a statistical analysis of the results but that has not been released yet. When it does come out it will be very interesting to see what the result has been.
Maybe some one has some figures from the US on what happened there when they lowered the speed limits about 1990 or so.
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The age old quote by the Slower Speeds Intitiative (hmmm, would you think they might be biased with a name like that?) given by NoWheels about the 1mph drop in speed gives 5% reduction in accidents is the most unscientific conclusion imaginable. If I did a survey and came up with that conclusion where I work, I'd be laughed at very hard.
I am still staggered that the whole concept of causation is totally ignored to twist gathered figures and measurements. This is very basic fundamental maths and statisics that any schoolboy should know, let alone someone producing statistics for public consumption.
Not only does the statement overlook the basics of causation, it makes a glaringly simplified assumption that if something increases it must give the same opposite reaction when it decreases. It is a total joke.
I have yet to see a genuinely impartial and correctly scientific survey done on the relationship between speed and accidents.
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I am still staggered that the whole concept of causation is totally ignored to twist gathered figures and measurements. This is very basic fundamental maths and statisics that any schoolboy should know, let alone someone producing statistics for public consumption.
And the expectation that we will all swallow it whole is, IMHO, an insult to our intelligence.
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Replying to tunacats question about average speeds in this country over the last 25 years. I haven't got any figures, but from my own personal experience, my average speeds have plummetted over the last decade. Not due to me choosing the drive more slowly, but the increase in congestion, traffic lights (forcing me to stop far more often), over-complex junctions, closed-off roads (increase journey lengths along busier roads), 'traffic calming' measures and speed cameras have all done this.
It'll be a massive task to obtain all the figures on this to get any decent results though!
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The age old quote by the Slower Speeds Intitiative (hmmm, would you think they might be biased with a name like that?) given by NoWheels about the 1mph drop in speed gives 5% reduction in accidents is the most unscientific conclusion imaginable. If I did a survey and came up with that conclusion where I work, I'd be laughed at very hard.
This is not research done by the Slower Speeds Intitiative, nor is it commissioned by them. It's government research, which the SSI is quoting.
Their assessment of the evidence is very similar to the assessment of the House of Commons select committes report to which I posted a link. If you don't want to believe the Slower Speeds Initiative, ignore them and see what a cross-party group of MPs concluded after hearing evidence from all sides: www.publications.parliament.uk/pa/cm200102/cmselec...m
Note that none of committe members voted against the commitee's conclusions on speed. The Committee unanimously agreed that slower speeds are safer.
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The Committee unanimously agreed that slower speeds are safer.
Of course they did. No doubt they noticed that the sky is blue, too.
Lower speeds are always safer. The safest car to be in, right now, is mine because it is stationary in the office car park!
Concluding that lower speeds are safer only helps guide policy to a man with a red flag.
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?All those factors have an effect on safety, and it wouldn't make sense to use data based on all those changes and draw conclusions about one factor in isolation. The usefulness of the studies on speed is that they do isolate just the one factor.?
But isn?t that then, at best, *all* this report is saying?
If we all do zero mph, there would be zero accidents. It?s natural sense then to expect that at lower speeds (drivers in a trace not withstanding) there will be fewer accidents.
But that isn?t of great use in the real world ? where would you draw the line on reducing the speed limits further and further?
Surely you DO have to take into account the greater numbers of vehicles on the road, greater typical journey distances, greater speeds on open roads, greater congestion in urban areas, etc, that have happened in the last 25 years.
If the ?number of accidents? hasn?t commensurately ?got worse?, then surely we?re actually doing quite well?
If that was, or is, the case, why not balance our castigation with the slogan ?Going slower does mean fewer accidents, but we?re doing alright ? keep up the good work.? ?
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For "trace" read "trance". Must have been in one.
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If we all do zero mph, there would be zero accidents. It?s natural sense then to expect that at lower speeds (drivers in a trace not withstanding) there will be fewer accidents. But that isn?t of great use in the real world ? where would you draw the line on reducing the speed limits further and further?
For myself, I'd be happy enough to leave most speed limits as they are for the moment (except for more 10mph and 20mph zones in residential streets and maybe an increased motorway limit) if we had much stricter enforcement.
Reducing actual trafic speeds to the current legal limits would have a huge benefit, particularly in built-up areas.
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TRL conclusion clearly illustrates the danger of misusing statistics:
Slower speeds are always safer - Motorways are our safest roads.
Quite clearly these two statements are mutually incompatible,
80mph on motorways is deemed to be safe in France and in Germany there are completely unrestricted motorways, extrapolate the 1mph slower causes 5% less accidents argument and it's a wonder there are any German drivers left!
IMHO inappropriate speed is a causal factor in a large number of accidents, we only way to approach this problem is to be pro-active about and enhance driver training.
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With the benefit of 40 years behind the wheel, my impression is that maximum speeds have increased but fatal accidents have come down.
But the steady reduction evident until 8 or 10 years ago has come to a halt.
When I was first on the road, 60mph was fast. Only sports cars would exceed 80mph.
Today every man and his dog does 70mph plus when traffic conditions allow.
What has changed is that driving standards have fallen. Racing off from traffic lights, tailgating, undertaking (often caused by middle lane hogging), lane switching, turning without indicating, observation, amber gambling, jumping red lights (even by buses, would you believe), etc., etc. have all got FAR worse.
IMHO reductions in speed limits have had a counter-productive effect by removing the perceived responsibility from the driver who then drives to the limit, or a couple of mph over, without considering whether that speed is APPROPRIATE. Thus you get 30mph past schools, 70mph in poor visibility or on wet roads or 60mph round bends on country roads. Result: CRUNCH and "But I wasn't exceeding the speed limit, Officer".
If the normal result of an accident was that someone was charged with careless driving, dangerous driving or manslaughter, rather than prosecuting millions of motorists for exceeding an arbitary and often inappropriate (in both directions) limit, then that link of personal responsibility for one's conduct would be restored.
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Absolutely.
And on that basis, I would have been prosecuted for due care & attention in 2001 when I fell asleep & woke up to see a queue of traffic a bit close in front (For those who've forgotten, my daughter was a few weeks old). As I d**m well should have been.
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Thanks for the reference NoWheels. As I sit I can hear traffic on the nearby 30 mph (nominal) road at the approach to the village: the law observing are barely audible. The law disregarding are clearly audible, from tyre noise mostly. Local drivers know the police do not bother, so in effect its the drivers decision as to the choice of speed. Many travel at speeds of 50 to 60 mph. Neighbour reckons, from recent walk, up to 70 or 80 on a straight 30 mph road on the other side of the estate, bordered by houses most of the way . That there aren't many fatal accidents is because some drivers, commuters mostly, have intimidated pedestrians off the road. It does have footpaths all the way, but it can be extremely unpleasant. Lack of thought for others is the problem.
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That there aren't many fatal accidents is because some drivers, commuters mostly, have intimidated pedestrians off the road. It does have footpaths all the way, but it can be extremely unpleasant. Lack of thought for others is the problem.
This is a point I raised a while back and got absolutely no response - bit close to home for some?! The use of injury and accident statistics as the only measure of the impact of speeding misses out an awful lot of the other anti-social effects of speeding and it is becoming increasingly common for pedestrians AND drivers to modify their routes to avoid "trouble-spots" caused by speeding motorists.
To pick up the earlier comment from Paul Smith (?) that he doesn't like the way that rsponsibility for speed control has been removed from the driver and handed to the government - when there are a significant number of drivers who fail to regulate their speed sensibly and safely, then the government is bound to take action.
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Lack of thought for others is the problem.
Agreed, no-one thinks about anyone else any more, and this applies to more than just driving.
[Help! - I sound old again! I'm not really!]
Re Myles' comments, many road safety messages are distilled down to a simplistic "slow down"*. Speed cameras are seen as a revenue-raiser by so many that it is endemic. Police drivers go at 90 on the M40 (see my post above). Generally, anything published by HMG is now seen as probably untrue/spun beyond recognition. The overall effect is that people don't listen, ignore the lot, and suit themselves.
So, by trying so hard to reduce speeds, we fail.
*[THINK! could have been a welcome change but managed to find a reason to slow down in every possible circumstance. Yes, I know you can, but it diluted the message]
There was an advert a while back that showed a car in a high street at 40 suddenly applying emergency braking. The voiceover said that if they'd been at 30 they would have stopped, ...., now. A few seconds later a child is catapulted into the air. That was excellent - it was in context (i.e. a place where high speed is innapropriate but often seen) and educated people as to the difference rather than just scolding them. Sadly, it seemed to have a short run and I haven't seen much of since.
This country's road safety "debate" depresses and frightens me. This site is one of the few places that it is intelligently argued.
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The depressing thing is that it plays on emotion by taking what is a pretty rare event (kids being knocked down on crossings)and making it seem that is the main danger to watch out for and you can relax if a pedestrian crossing isn't in sight.
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The depressing thing is that it plays on emotion by taking what is a pretty rare event (kids being knocked down on crossings)and making it seem that is the main danger to watch out for and you can relax if a pedestrian crossing isn't in sight.
sadly, very true :(
As Nortones pointed out, those drivers who use excessive speed in built up areas "have intimidated pedestrians off the road". That's particularly true of children -- the reason that the UK has such low rates of accidents involving children is that British kids have been kept away from the roads.
That's why talk of reducing speeds at pedestrian crossings, near schools etc, is missing the point. Unless speeds are greatly lowered in all built-up areas, children will continue to be kept indoors for safety reasons.
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Agreed. We live on a VERY residential road. Cars parked, no straight sections, many driveways, 30 limit, should be 20. Top speed observed was 48mph. No, I'm not kidding.
Very few kids to be seen - ours stay in the back garden unless accompanied.
Sadly, the only youngsters we see are teenage ones behind the wheel, usually somewhere between 30 and 48.
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I live in a close 10 houses long (about 100 yards).
No need to go above about 20/25mph, but have seen 40mph or so.
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I'm not going to get involved in the argument....sod it - I am. I completely agree with lowering speed limits near schools but NoWheels comment about leaving most of them "as they are" I'm sorry, but I must completey disagree although I am unable to back that up with any impressive sounding evidence at all.
I must however leave you with this,
near my house, there is a primary school but on a very residential road. That is to say, it isn't a main road, just a housing estate with a school on. The council, in their wisdom have put the "traffic calming" speed bumps that buses can straddle and presumable ambulances. However, what is slightly odd is that they have done this on only one side of the road at one end and the other side at the other end. The result of course is car drivers who value their suspension veering over to the wrong side of the road to miss them out completely. This can be rather scary when you're on the right had side of the road (right as in correct) and the other person....isn't. I don't advocate speed bumps but I'd rather have them on both sides where in this case, it has to be safer.
*Rant over*
thanks
Adam
--
"Ah...beer - my only weakness - my achilles heel if you will"
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Where people go worng in any argument about speed is when they start to compare their skills and abilities with those of anyone else.
Sadly there are too many nonsense speakers on both sides.
Firstly there are some irrefutable facts:
1. A car travelling at a higher speed causes more damage to what it hits than the same car travelling at a lower speed.
2. The braking distances of a car are roughly as follows:
50 mph x yards
70 mph 2x yards
100 mph 4x yards
In other words all other things being equal a car travelling at 100 mph on a mototway takes as long to slow form 100 to 70 as it does from 70 to 0.
3. For any driver, no matter how good their anticipation and reaction time is they will, have travelled further before they can possibly take any action the faster they are traveling.
The overall effect of all this is that when the unexpected happens you need more distance to react, or take evasive action, the faster that you choose to travel.
When you do react by slamming on the brakes you will take longer to stop the faster that you are travelling and if you do not manage to stop completely the speed at which you impact will be higher causing more damage.
If an incident happens when you are travelling at a higher speed it is harder to avoid amd more damage is caused if you do have an impact.
Overall therefore every individual is safer travelling at a lower speed rather than a higher one.
Whether any one individual travelling at 90 is safer or more dangerous than another driver travelling at 70 is a different question, impossible to answer, and irrelevant.
Anyone else get caught on the A1 today? It took me 2 hours to travel 5 miles around Peterborough!
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Best we all get a red flag, then.
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