Regression to the mean is explained here:
www.safespeed.org.uk/rttm.html
If limiting speed doesn't reduce accidents what other purpose is there?
The camera data is very selective. Just because accidents drop at a camera site doesn't mean that the camera had anything to do with it unless you have a control site or study sites where there have been a number of ksis and compare them. Pharmaceutical manafacturers use the same tricks to hide data which doesn't support them, it is wrong when they do it and it is certainly wrong when safety partnerships are doing it. The safety partnerships are entirely ignoring this point, along with regression to the mean it is entirely possible that cameras do nothing. The sites that aren't showing a reduction now might suddenly change and show a reduction in the future. And by the same token sites which are showing a reduction in ksis now might suddenly switch into an increase of accidents. This is the nature of accidents. They occur in random places and cluster in certain others.
Proving cameras increase fatalities is the same as proving they don't, you need control sites where there are no cameras and they need to be compared over a number of years. Durham is a good example as they have no fixed speed cameras and enforcement by traffic police. This is why the data for the camera partnerships that have been in the netting off scheme has shown an increase in fatalities at a number of sites as they have been in place long enough for the accident rates to return to 'normal'. Considering there are 5000 camera sites an alleged 100 lives saved a year is pretty poor, and seeing as we used to have improvements in fatality reductions much greater than that year on year before cameras. If those reductions had been matched in the last 10 years there would be several thousand more people alive today, much more than the 100 a year that the cameras are supposed to be saving.
I agree with Mark's comment in that the whole issue of speed limits need to be looked at and at how they are set. If limits are reasonable then the level of disobedience is much reduced. eg over 50% of vehicles speed in 30 limits but only 10% of vehicles do in 40 mph limits.
I am against the enforcement of limits where there is no discrimmination in whether it is a safe thing to do or not. 35 mph in the wet outside a school is far more dangerous than 75 on motorway in the dry yet enforcement by camera treats both cases the same. Either have some discretion or raise the limit on the motorway and reduce the limit outside schools and enforce them properly. Cameras don't do this as they have no idea about whether or traffic conditions. It is doing nothing for driver education when people are just bimbling along at whatever the speed limit is assuming that it is safe. There is no way you could argue that doing 45 in a 40 that was a 60 limit the week before is any more dangerous than when the limit was 60, but it would be a technical infringement.
I do not wish traffic police to avoid enforcing limits because they are in the most part rational human beings who are able to tell people why there driving was inappropriate and actually dangerous. Traffic police would be pulling people who were driving dangerously and more importantly if there were more of them they could be getting their hands on the uninsured, untaxed and criminal sections. The normal motorist that just speeds a bit but within reason would be left alone.
teabelly
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Hear, hear. Statistics can be, and are, manipulated to suit the political opinion of those who are using them. For any enquiry to be credible, it must be undertaken by truly independent mathematicians.
I agree with teabelly - what other benefits can there possibly be to reducing speed other than reducing accidents?
--
Mattster
Boycott shoddy build and reliability.
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Hear, hear. Statistics can be, and are, manipulated to suit the political opinion of those who are using them. For any enquiry to be credible, it must be undertaken by truly independent mathematicians.
There are actually some pretty strict codes in place these days about govt statistics -- if there weren't, then all the major macroeconomic and budgetary indicators would be ignored by the financial markets. There may still room for some tweaking around the edges, but not for outright fiddling.
If you don't believe any government figures, and rely only on those from third parties -- well that's your privelige, but you'll be hard-pushed to find any MP of any party who agrees with you.
I agree with teabelly - what other benefits can there possibly be to reducing speed other than reducing accidents?
Lots!
Lower speed means less noise, which is particularly important on residential streets.
Lower speeds in urban areas means a reduced acceleration/breaking cycle ... which means less fuel wasted, less pollution, and smoother flowing traffic, as well as less stress for drivers.
Lower vehicle speeds makes life much safer for cyclists and horse-riders, whose maximum speed doesn't increase, and who face increasing danger as car speeds rise. Of course, increased speeds may mean fewer accidents, as cyclists give up trying to use the road -- a reduced accident rate may merely mean that they have effectively been pushed out.
Lower speeds makes it safer for people to cross the road. On one stretch of road I use, where there is no formal crossing point for half a mile either way, there used be an unpoliced 40mph limit. It was so dangerous for people to cross that many of those least able to manage the journey went on to the crossing point: now, in a monitored 30mph limit, many of those same people avoid an extra half-mile walk because it is that much safer to cross.
Then consider a residential street. Children playing often wander out without looking properly, so when speeds are high, many parents simply do not allow their children to play outside. Reduce the speeds to human-friendly levels, and children regain their freedom (with huge benefits to physical and psychological health, both of which indicators are horrifying in today's kids).
I could go on ... but the reasons for reducing and limiting speed go far beyond anything that can be shown by the accident figures.
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There are plenty of reasons for reducing speeds in certain areas, and NoWheels has set out most of them. These are valid reasons.
They don't help justify cameras, of course, because the residential roads to which they apply do not have cameras. Near me, the cameras are set up to police the main road where most cars drift along at 35, rather than the residential street where we have measured speeds of 48 on a downhill stretch. I know which is more dangerous, but the 48 on a side street is rare so does not raise enough revenue.
Nevertheless, they are valid reasons for other forms of speed control.
I'm also going to put forward a reason for higher speeds. I know this is heresey in today's climate, but so be it. My office is in a village, which has one shop - a newsagent. If I need to go shopping at lunchtime, the nearest town is at the other end of an A road. That A road used to be a 60 limit, and I used it every few days. I never once saw an accident on that road in the 4 years that I used it regularly. That does not mean that there were none, of course, but if it was a blackspot then I would expect to have heard about some, at least.
They have now "upgraded" the road by various forms of engineering work which, from the time taken, I would estimate cost a considerable sum. As a result, most of the road is now a 50 limit with long stretches of 40.
Previously, in a one hour lunch break I could eat a sandwich, drive to the town, spend about 15 mins shopping, and drive back. The reduction in speed that has been imposed means that the 15 mins shopping "window" is now gone. I can just about get there and peek in the shop window before I have to come home.
Now, this frees up time over lunch to visit the BR, so it has some benefits. However, I have suffered a loss of amenity, and the shopkeepers of the local town have suffered a loss of turnover. Multiply that by every worker in the villages around the town and it is, I would suggest, significant.
To what end? The road was an uninhabited country A road with (to my knowledge) no safety problem and no-one to upset. The only winner is political correctness; the local authority has no doubt gained brownie points for reducing speeds in the county.
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There are plenty of reasons for reducing speeds in certain areas, and NoWheels has set out most of them. These are valid reasons. They don't help justify cameras, of course, because the residential roads to which they apply do not have cameras.
Patently, that's a false assumption, on two counts.
First, three of the four cameras near me are all situated at the frontage of houses: the fourth one is outside a field, the only unbuilt space on that stretch. However, that one is actually the closest to the junction at the entrance to the local grammar school. That site was also the point of most of the fatal accidents which occurred before the cameras were installed (though interestingly the fatal accidents at that site all occurred well after school hours).
Secondly, these points don't only apply to residential streets, e.g.
"reduced acceleration/breaking cycle" applies very well to one of the other camera-monitored roads in my town, which is a congested urban dual carriageway. It's much less frenetic since monitoring started, and much easier to drive on.
Making life safer for cyclists and horse-riders applies to all roads, urban or rural: the crucial factors there are visibility, road width and traffic density. When I was a cyclist, I had no prob with wide 60mph A-roads, but a busy narrow road at 40 was a nightmare.
Increasing safety for people crossing roads applies to most urban routes, regardless of whether or not there is residential frontage. Of course, an alternative would be to instal pedestrian-controlled traffic light crossings every 50 or 100 yards, but apart from the huge cost, most drivers would object strongly to the disruption.
As I said, there are lots of other reasons for limiting speed: another important reason is to reduce speed differentials, which is particularly important on roads with junctions.
A rural road (hardly any houses) about three miles in the other direction has had a 50mph limit reduced to a 40, and cameras installed. The result has been that the plethora of moderately-used junctions on that stretch can now be navigated without taking your life in your hands, and without a speedster shooting up your tail as you accelerate away from one of them.
The point you make about the 48 in the residential street is interesting: I quite agree that it's much more dangerous than the 35 in the nearby 30mph. My own street has almost exactly the same problem, except that we have a blind bend to add to the fun (a downhill blind bend with reverse camber, v dangerous).
However, there is a balancing equation here. I hope that we could agree that enforcement activities should be applied where the resources required will have most impact -- so let's try a very rough prioritisation using degree of danger and incidence of danger.
Let's give a danger-rating of 10 points to idiots doing 48 down my street, and a danger-rating of 1 point to the folks doing 35 in the 30 zone. (We could mull over the ranking, but the 10-1 ratio probably isn't that far out; maybe 5-1 or 20-1 would be the outer limits of the range if we analysed it all)
However, the traffic levels and extent of speeding also need to be taken into account. The main road a mile away has at least a hundred times as much traffic, and probably several hundred ... but let's take 100 as the figure.
(To be even fairer, I probably should note what we really want to compare here is ratio of vehicles at an excessive speed. Nearly all the vehicles on the main road exceeded 35 before cameras were installed, whereas only a small minority of the cars on my street exceed 25, and only a tiny number exceed 35mph. If we applied those figures, the ratio of traffic at an excessive speed would actually be much greater than the 100-1 ratio of overall traffic volumes)
So the residential street gets has 10 danger points multiplied by ten for the volume, and the main road gets 1 danger point multiplied by 100 for volume. That suggests that it's ten times more important to restrain speeding on the main road ... which is why the cameras have been installed there.
My local police have responded to residents' complaints by deploying mobile cameras at random around the residential streets, which has helped quite a bit (though it's nowhere near as good as a permanent camera). Maybe your local police could be persuaded to do the same thing?
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The majority of car drivers do considerably more than 70 mph, most of the time, on the motorways. But most stretches do not (yet) have cameras on them, and police patrols do not tend to pull someone over unless they are blatantly doing over 85. There is thus general consensus, even amongst the enforcers, that the law in this case is an ass, and that breaking it is not causing undue extra harm or risk to anyone.
(Whilst a larger traffic volume must increase the possibility of an accident, I?m not convinced that a simple up-scaling can be applied. On a motorway there?s a large volume and majority speeding, but not large numbers of accidents. The suitability of the road must be taken into account.)
Lower speeds reduces noise in residential areas. Yes. So why not also make more efforts to prosecute the Saxos et al which have drainpipe exhausts and thumpin? choons?
Lower speeds in residential areas reduces pollution, wastes less fuel, and less damage to straying children. Yes. So why not also, in these same residential areas, clamp down on smoking cigarettes in the street, and people driving thirsty 4x4 iron when a Honda Civic would fit the bill?
Away from residential areas, away from the accelerate/brake cycle, on trunk roads where you can cruise, noise, fuel waste, and risk to pedestrians are not factors worthy of such strong consideration. And again, breaking what is the law does not *necessarily* result in spiralling deaths and injuries.
If I do 81 in a 70 and overtake someone on a clear stretch of dual carriageway, and I complete the manoeuvre without hitting them, I have not caused them any harm or inconvenience. This is not the same as shoplifting or burglary. Yes I posed extra risk, but it was minimal, acceptable even, seeing as it is similar to the way in which most of us pose minimal extra risk to each other day in, day out, on the motorway, but do not get prosecuted because the police agree that it is still safe, within reasonableness, to break this speed limit law.
So seemingly the worst that could be levelled at me by the people I overtook was that I was momentarily being antisocial, buffeting them with my wake.
But cameras do tend to be placed on these trunk roads, where the limit has often recently been reduced. So here, you get prosecuted for being antisocial whilst posing little extra risk.
But strangely, in residential streets, where extra speed means significant extra risk, there are few cameras. And you can be pretty much as antisocial as you like with noise and bullbars and cigarette smoke. Little chance of being prosecuted.
Doesn?t make sense.
?We want people to consider speeding as antisocial as drink-driving?. Well their methods are backfiring at the moment.
The public are not such great fools: It is implicit that breaking the speed limit on the motorway by 20% is neither unsafe nor antisocial. And most agree with No Wheels that breaking the speed limit in residential areas IS unsafe and antisocial, but they are weak in practicing what they preach.
In the middle ground are the roads where it is still safe to speed by a certain amount, and it?s not particularly antisocial to do so. But sadly this is where most cameras are.
This degrades support and breeds mistrust, and is why speed cameras is such an emotive subject.
As Mark(RB) says, set realistic limits: Restore the trunk roads their previous 60 and 70, make the motorways 80 or 85, and make residential areas 25 or 20.
THEN deploy the cameras. THEN gain the public?s support, trust, and change their mindset.
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The majority of car drivers do considerably more than 70 mph, most of the time, on the motorways. But most stretches do not (yet) have cameras on them, and police patrols do not tend to pull someone over unless they are blatantly doing over 85. There is thus general consensus, even amongst the enforcers, that the law in this case is an ass, and that breaking it is not causing undue extra harm or risk to anyone.
Tunacat, lack of enforcement does not actually indicate a consensus that it's a bad idea -- merely that enforcement by patrol cars is expensive and difficult.
A vehicle doing over 80 on even a moderately busy mway is hugely increasing the speed differential over the 65mph-limited trucks in the inside lane, which has a whole load of damaging effects. That's why very few safety experts support raising the limit.
Cameras should really be much more widely deployed on the mways, but the reason -- ironically -- is a political one.
So many drivers have been used to routinely breaking the limits that their widespread deployment causes howls -- so govt decrees that they should only be deployed at accident hotspots.
As result, they aren't deployed very widely on mways, where most safety experts agree that limiting speed differentials is very impt.
Damned if you do, damned if you don't -- that's the situation the authorities face in deploying speed-enforcement techniques
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If there were horrendously loads of m-way accidents due to speed, surely stringent measures would be taken to reduce the speeds, however expensive and difficult.
The traffic's already doing these speeds (with the resultant differentials), so I assume the present level of accidents on m-ways must be 'acceptable', in some loose sense.
In which case, why NOT increase the limit to what everyone is already doing, AND then install cameras? Thus, without penalising current rates of travel, the public would become used to cameras being used, acceptably, to enforce 'correct' speed limits, become more accepting of them, and obey other limits (on less safe roads) more thoughtfully and willingly.
Which we are told is the desired end-result.
Nanny-state finger-wagging and inappropriate limits and camera sitings just breed contempt.
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OK. So 80 in the outside lane is too fast, but only next to trucks limited to 65. Their limit was set decades ago and technology has advanced. Let's take advantage of that technology and look again at the truck limit, for motorways.
Lack of enforcement may well not indicate a consensus that it's a bad idea, but the sheer number of chief constables and home secretaries that have been caught speding does.
One rule for them, another for us plebs?
mways, where most safety experts agree that limiting speed differentials is very impt.
Which ones? Motorways are, statistically, our safest roads.
Damned if you do, damned if you don't
If so, it sounds to me as if the basic approach is flawed.
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"If I do 81 in a 70 and overtake someone on a clear stretch of dual carriageway, and I complete the manoeuvre without hitting them, I have not caused them any harm or inconvenience. This is not the same as shoplifting or burglary."
And if someone attempts a burglary and fails, they haven't caused anyone any harm. If they're caught in the act would you suggest we let them go?
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"As Mark(RB) says, set realistic limits: Restore the trunk roads their previous 60 and 70, make the motorways 80 or 85, and make residential areas 25 or 20."
I could agree, if it were not for the fact that some people would then demand the right to drive at 80 on trunk roads and 90 or 95 on motorways, because it's only a little bit over the limit, not doing anyone any harm, and they're so used to "getting away with it".
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You?re twisting things here, SR.
A burglar?s actions have deliberate intent which will result in (at best) inconvenience to others. An above-the-limit overtaker?s actions have no deliberate intent to inconvenience anyone.
Both are breaking the law, and should be punished if it is possible to do so, but the evil intentions cannot be classed as the same.
And in the second piece, I was trying to put forward a genuine and constructive route to gaining more widespread acceptance of speed cameras and compliance with limits.
I don?t think that the MAJORITY of people actually break the limit just for the sake of it. They just want to make decent progress, at a speed which feels safe enough to them.
Set limits the drivers agree with on the motorways and trunk routes, then use cameras to trap those who break THOSE limits, thus penalising the true speeders rather than the ?sensible, but breaking the current limit? majority, who then increase their support for and trust in cameras. Then expand the camera usage in residential areas and LOWER the limits there.
As No Wheels has said, draconian measures would result in political backlash. But so do cynical methods, to a lesser extent: The way speed cameras have been used so far has NOT gained the general support of drivers, it?s done the reverse. There?s thus already work to be done before we can even start from a neutral standpoint. If the compliance with posted limits in general is to be achieved, and achieved, we are told, through a change of mindset, then it appears necessary to try a different strategy from that used so far.
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I don?t think that the MAJORITY of people actually break the limit just for the sake of it. They just want to make decent progress, at a speed which feels safe enough to them.
Tunacat, I'm inclined to agree with you.
I think that only a fairly small proportion of drivers are intentionally reckless, although a rather largely proportion seem to me to be disappintingly careless in their risk assessment. But I do agree that a majority of drivers probably do try to make a reasoned judgment about safe speeds.
Howevber ... while drivers' perceptions of what is a safe speed for them may be sound, in many cases it is not well-founded in reality, and in particular it may not adequately include the safety of other road-users.
There is also a deep resistance among many drivers to considering other factors such as non-car road users, non-road users etc, never mind more complicated speed-related factors such as speed differentials, the impact of speed on congestion etc.
In the last few decades, car have become immensely safer for their occupants: seat belts, airbags, improved handling, computer-modelled crumple zones, ABS disk brakes etc have all made it much easier for vehicle occupants to survive a crash, and (to a lesser extent) to avoid one. However, the crash survivability of pedestrians and cyclists has barely improved at all, and in some ways it has declined (e.g. from the spread of 4X4s) ... while the growth of car use increases their exposure to these risks.
So drivers rightly understand how their safety is improving, and (as plenty of research demonstrates) they absorb that safety margin in increased speed and risk-taking.
Meanwhile, policy-makers have to consider the other factors, from which drivers are increasingly able to distance themselves. The result is a huge (and growing) gap in understanding between drivers and policy-makers about what may be the relevant factors in determining safe speeds, let alone the role of enforcement.
It's a real pity that some motoring bodies (such as the ABD) seem to want to avoid that wider discussion, though it has been encouraging to see the RAC and others starting to try to engage with it.
But the way things are going, I fear that we're heading for a prolonged (and increasingly heated) dialogue of the deaf, in which both sides conduct a displaced argument about enfocrement without ever developing any shared understanding of what enforcement might actually be for.
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Are you right, NW? I cannot substantiate this point, but I understood - that bull-bars notwithstanding - a pedestrian was much more likely to survive a collision with a modern car than with an old one.
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Are you right, NW? I cannot substantiate this point, but I understood - that bull-bars notwithstanding - a pedestrian was much more likely to survive a collision with a modern car than with an old one.
I think I'm broadly right :) ...
... though maybe I should have acknowledged some of the gains which have been made.
Sure, a modern car has fewer protruding sharp objects etc and doesn't have metal bumper, so is marginally safer, although newer features (like very soft front ends, deformable bonnets etc) are still not widely deployed. But for most purposes, it's still solid metal hitting bones, which is not so much fun ... and the gains there are much much less than for the driver who has (over the same time period) gained airbags, seatbelt, collapsible steering column etc etc
"Bullbars" obviously cause a particularly severe hazard to pedestrians, but the height of 4X4s is also a real hazard even without the people-cruncher-bars (which is how they ought to be named). Because of the height and the ground-clearance, pedestrians are much more likely to be pushed under the vehicle and squashed rather than scooped up onto the windscreen. The US NTSA (NRTSA???) has published some research which I found a few weeks ago, but canna remember the URL
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Fair points, NW.
However, many of them could be dealt with in ways other than cameras. You acknowledged that you felt safe cycling on a wide 60-limit A road. So, when faced with your problematic 40-limit road, the authorities could either improve the road and lift the limit to 60, or they could leave it as it is, drop the limit to 30 and plaster it with cameras.
They tend to choose the latter, and my lunchtime shopping trip vanishes as a result. Bit by bit, we all suffer in this way - a thousand cuts and all that.
NB: I don't know where you live, but I suspect we live in different areas and I do accept that improving the road may be a more viable option near me than near you. Nevertheless, it doesn't seem to happen.
As regards your points system, I have to disagree with you. I think, in fact, that this is pretty well exactly what camera partnerships do. It is wrong, because it loses sight of the effect of an accident. The 48 on a residential road, if it causes an accident, will almost certainly kill. (Incidentally - our one is also a downhill stretch, with a blind bend and adverse camber - perhaps we are closer than I thought!). The many many 35s on the through road will annoy, yes, but will not be as serious since there are good sightlines, few pedestrians, and thus time to brake before you hit the other person in their metal box. But there are so many of 35ers that they swamp the few 48s.
More seriously, although a points-based approach is not the same as an approach designed simply to maximise revenue, it is (from the outside) indistinguishable. It is therefore a source of the loss of respect for the law and the police that we have observed. That loss of respect has, IMHO, made our roads more dangerous and will be difficult to reverse.
BTW - we have been (collectively) asking the local authorities for help with controlling speed on the road. We regularly get flat refusals. We have even been told that if we put warning signs in our own gardens then we will be prosecuted. Charming.
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Perhaps the dutch model where pavements are removed and roads become integrated with pedestrians, cyclists and whoever all mingling together in one space. It removes the priority system and as a result pedestrians and drivers become more aware of each other as there are blurred boundaries.
There also seems to be some research that having road markings increases driver likelihood to drive at inappropriate speeds.I think it had something to do with risk homeostatis. I have noticed that when the road markings are removed after resurfacing, even after the chippings have gone drivers do drive that little bit more slowly. Once the lines go back normal service is resumed.
Another interesting snippet from some of the online journals I have access too (it's great working in a university some time!)
Apart from incentive programmes, there is one other factor that has repeatedly been shown to have a major effect on the accident rate. This is the business cycle . Whenever the economy is in an upswing, the traffic death rate per head of population increases, whereas it drops during recessions (Adams, 1985; Partyka, 1984). Correlations between the annual variations in the rate of employment among those willing to work and the death rate on the road have been found to range from about r 5 .7 to r 5 .9 in countries including Canada, Finland, West Germany (prior to uni cation), The Netherlands, Sweden, the United Kingdom, and the United States (Wilde, 1991). When the index of industrial production and the ratio of young people to the total population was included as well, multiple correlation between the variations in economic prosperity and the traffic death rate per head of population in Switzerland was seen to amount to r 5 .97 (Wilde & Simonet, 1996).
teabelly
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Perhaps the problem lies in our historical habit of having villages bunched around a main road. All the traffic is then directed right through the centre of habitation.
Why can't we have a variant of the Dutch model with VERY SLOW areas in the middle of population centres and decent bypasses directing through traffic away from danger?
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Teabelly, that's intereresting data on the business cycle. It the reduction shown per head of population or per mile travelled? (I assume that mileage declines in a recession)
Either way, though, it makes sense that a situation which requires economic caution also generates caution on the road. However, I'm not entirely sure that it is useable in formulating a road safety policy: engineering a recession to reduce RTAs might not be a vote-winner at election time! I suppose it might go some way to explaining the slowdown in the reducing trend of KSIs in the last few years in the UK.
The Dutch model of mixed-used streets is being deployed in the UK, though on a small-scale. The Joseph Rowntree Foundation has published some research on trials of what it terms Home Zones: "A home zone is a residential street where people come before vehicles" -- www.jrf.org.uk/knowledge/findings/socialpolicy/d41...p
It's an idea I really like, but I can imagine that those who object even to speed bumps might burst in apoplexy at this one!
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NW, I'll see if I can find more data on how the fatalities were calculated. It is in a whole research paper with all sorts of theories on accidents and fatality rates. I'll have a read and see if there are any other interesting snippets.
I can't stand speed humps as they're a way of slowing people down that causes frustration and unintended negative consequences. The dutch idea is much better to me as it makes an environment where people choose to slow down and be more observant but they don't realise they are being manipulated into it which I am all for :-) I don't know whether our home zones are just ordinary streets with a 20 mph limit slapped on or a proper re-engineering project.
teabelly
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Teabelly, thanks for the homeostasis document: very interesting reading.
It's particularly interesting to see an empirical examination of the potential negative effects of driver training and vehicle safety measures. The paper seems to give support to the sort of hazard-perception training offered by the IAM, while warning against the sort of vehicle-control-skills training favoured by the police.
AFAICS, the Home Zones here are much more than just reduced speed limits -- they are completely re-engineered streets.
Two useful links:
www.homezonenews.org.uk/ for general guidance on Home Zones and how to go about establishing them
and www.homezoneschallenge.com/ for details of particular Home Zone projects (badly arranged site, but useful pictures if you burrow)
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It seems that it is in fact the accident risk itself which increases and that even with extra miles travelled the overall risk increases for each person for each mile travelled.
I was going to summarise the entire article but it is full of all sorts of interesting stuff so I have dumped a copy in my webspace: tinyurl.com/2u6op
teabelly
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Patently, making every 40mph limited road into one capable of 60 would involve a massive road-building program -- bigger than anything ever seen. Even if the funds were available, I can't see the popular support for such a massive transformation of our evironment.
It's inteersting looking at this comparison of the through road versus the residential road. I think you hit the nail on the head when you point out that "there are so many 35ers that they swamp the few 48s" -- it's that huge numerical imbalance that means that in the end, the 35mph zone is the one which has the most accidents. In our area, all the fatalities were on the main road which now has the cameras.
The sort of points-based system used for choosing camera locations is actually pretty similar to the system which the DoT uses for planning road safety measures. They allocate a value to a life, and calculate whether the value of the lives saved outweighs the cost of the safety measure.
Any such cost/benefit calculations look pretty callous from the outside, just as a well-planned camera system may appear to be revenue-driven ... but in the end, resources are limited and choices must be made.
I'd love to have a camera on my street, but I'm not sure that I could justify it as a priority over five other similar locations in the area. They'd all rank about the same, and any one of them would achieve much less overall gain than has been achieved on the main road. That's why the cameras went on the main road, and the flat streets nearby got speedbumps -- much cheaper.
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Patently, making every 40mph limited road into one capable of 60 would involve a massive road-building program
Of course - I just said that when presented with a problem road, the response is to slow everything down rather than make it safer or more usable.
One purpose of roads is to convey people from A to B swiftly safely and efficiently. Let's not forget that!
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"They don't help justify cameras, of course, because the residential roads to which they apply do not have cameras. Near me, the cameras are set up to police the main road where most cars drift along at 35, rather than the residential street where we have measured speeds of 48 on a downhill stretch. I know which is more dangerous, but the 48 on a side street is rare so does not raise enough revenue."
If the cameras were set up in the residential area, the traffic speeds on the main road would no doubt increase. What then - move it back again? Have there actually been a lot of accidents on the residential street? If not, you should really wiat until a few people are killed before expecting any change.
Solution - remove the static camera from the main road and use mobile, covert cameras on BOTH roads, and all others in the area - and publicise this fact.
The problem is not the siting of the camera, but the behaviour of drivers.
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Would those who take the view that exceeding the posted speed limit in all circumstances is dangerous also carry that logic to its conclusion: that all such cases should be treated as dangerous driving and charged as such?
If not, then surely the case for automatic prosecution for exceeding the speed limit is invalid.
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With reference to the large post I left in the last thread, NoWheels is rather well showing exactly the reasons why a discussion about cameras is both pointless and fruitless.
Go straight for the mechanism about how the decisions are made, what the resultant regulations (incl. speed limits) are and you'll solve the problem, or at least if you don't solve it, you will be addressing it.
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Mark, you're right, as ever. Perhaps we should form a political party?
(Oops - no politics allowed here though)
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"Would those who take the view that exceeding the posted speed limit in all circumstances is dangerous also carry that logic to its conclusion: that all such cases should be treated as dangerous driving and charged as such?"
No more than you would take the view that merely driving, like many daily activities, carries and inherent element of danger; and that anyone caught driving should automatically be guilty of dangerous driving.
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I was trying to be serious!
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"If limiting speed doesn't reduce accidents what other purpose is there?"
Reducing the consequences of accidents when they occur, and making it easier for us all to co-exist on the same roads.
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Blimey, is Toad of Toad Hall back but on the other side of the fence?
P@rp, p@rp!
--
Terry
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Shopping in 15 minutes? Lucky they don't have speed cameras on the pavements of your nearest town.
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Shopping in 15 minutes? Lucky they don't have speed cameras on the pavements of your nearest town.
It requires a surgical strike - know what you want ... know where to get it ... in ... acquire target ... quick getaway.
They will need street cameras when I try and do it in 2 minutes!
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With regard to the economic cycle, it's a well-known fact that tube-use peaked at the peak of the last economic cycle ('87?) and has never reached that level since. I dare say miles travelled has a similar correlation - more business miles travelled, and more money to spend on 'pleasure' travelling - though that may be an oxymoron.
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PATENTLY,
"I also agree wholeheartedly that the common response from some to any criticism of cameras is that I must therefore want to speed dangerously without regard for life and limb. I accept that my choice of vehicles doesn't help me here, but it really isn't the case. It saddens me that some people are apparently unable to understand that there can be a middle view.
(In fact, I'm now so sick of that assumption I don't intend to reply to one particular contributor - it's pointless)"
I trust that was not aimed at me. If it was, I would like to offer you the opportunity to back up your statement regarding you being accused of speeding "dangerously without regard for life and limb". If and when you find it I will apologise unreservedly. If you don't, I expect you to do likewise.
I, for one, am well aware that there is a middle ground, but this tends to get lost in the hysterical "he's in favour of speed cameras so he must want us all to drive at 2mph" attempts to devalue others' points by mis-quoting, taking their views to extremes and attributing opinions that aren't actually true.
It would be a pity if we can't have a healthy debate between people of differing views without someone resorting to personal comments.
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It would be a pity if we can't have a healthy debate between people of differing views without someone resorting to personal comments.
Whether Patently aimed that remark at you or not is not material. You've now made it a personal comment. Select your favourite petard sir, and get hoisting.
On a wider note it's interesting (yawn) that this debate now has over 2,200 posts and yet still we go round the same arguments.
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On a wider note it's interesting (yawn) that this debate now has over 2,200 posts and yet still we go round the same arguments.
I suggest that ongoing debate is inevitable in any situation where there is a genuine conflict of interests and no sign of a mutually-acceptable solution.
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>a mutually-acceptable solution.
Which would, of course, require a willingness to compromise, a willingness and ability to "see the other point of view" and finally some level of open-mindedness, truth, honesty and frankness.
It would also need to appreciate differing motivations, differing wants and needs, differing levels of ability, and different agendas; Understanding different emotions, different concerns and an appreciation of the worth and the value of opinions, even when they differ from your own, without a need to either stamp on them or drown them.
Given that, I reckon that we're good for another 10 million posts going around the same old circles yet.
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Just to add more fuel in the fire of going round in circles here is another explanation of regression to the mean:
www.numberwatch.co.uk/2004_June.htm#speed
And from the pdf I posted earlier a possible justification why artificially lowering speed limits or rigid enforcement increases accident risk:
Due to the inevitable uncertainty of the outcome of any given action, the human brain has learned to optimise its degree of psycho-physiological arousal. A lower than optimal arousal would reduce our readiness to deal with a sudden threat; a higher than optimal level would soon exhaust our nervous resources. Physical risk, therefore, cannot be removed with impunity from the traffic system by a massive lowering of legal speed limits or any technical intervention aimed at the same effect. Such measures would be expected to produce a reduction in alertness and, hence, induce a state of behavioural adaptation to new conditions which is less capable of dealing with unexpected threats. A major decrease in the traffic accident rate per capita would, therefore, remain doubtful. If coercive speed reduction were successful in curtailing speed, this would likely amount to reversing the historical trend and thus lead to a reduced road mobility per head of population and a higher accident rate per kilometre driven.
So that's why we should allow speeding!
And round we go again :-)
teabelly
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So that's why we should allow speeding!
Actually, it's not an rgument in favouring of allowing speeding, it's an argument in favour of increasing stimuli and perceived risk. The solution is to make cars noisier and more uncomfortable, and make it it feel harder to control them safely :)
I recall that a version of that argument was used by Issignois wrt to the Mini: he reckoned that cosseting drivers with comfortable seats etc reduced their alterness.
Of course, it's all a variant of the seatbelt+airbag versus spike-on-the-sterering-wheel dilemma
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Noisier and more uncomfortable? Excellent idea: large V8s with dellorto carbs, rock hard seats and bouncy american suspension for everyone then :-)
More seriously perhaps the removal of stimuli such as torque steer has led to people being less aware of cornering and acceleration forces. Cars have power steering too which removes a degree of feedback from road surfaces which again reduces stimuli and gives a greater feeling of remoteness which could add to the comfort effect.
teabelly
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PATENTLY,
No need to shout ;-)
Logically speaking, if I was referring to you then I can't reply in order to explain why...
Nevertheless, I shall make an exception as your question is not (strictly) to do with speeding or cameras. My observation relates to the assumption which has, over time, appeared to be behind your comments. The style and content of your posts point to a very intolerant attitude towards those who travel above the speed limit. I should point out that this group included at least 57% of all drivers on UK motorways. Some comments that you have made in the distant past have indeed caused me offence.
I shall however give the milder but more recent example which triggered my decision not to reply:
www.honestjohn.co.uk/forum/post/index.htm?t=22716&...e
where you comment that you are looking for people to "regard others' safety as more important than their own pursuit of speed". This implies (to me) that you regard those who wish to make progress swiftly as, in effect, reckless as to the safety of others. I do not see any such correlation and find the implied comment as to my personal attitudes to be somewhat insulting. I see little distinction between the safety of others being a lower priority than my own speed, and me speeding "dangerously without regard for life and limb".
A stronger motivation for thinking again about whether to contribute further to this debate was that I feel that we have reached a position where further discussion is unlikely to bring any of us closer. It is perhaps reaching a tit for tat stage where neither of us is able to persuade the other. To that extent, Mark was right.
I replied to NoWheels because her views and comments change in the light of what she is replying to. Yours don't, so I feel that there is little point. To be fair, neither do mine any more. This is what makes me feel that neither of us is making any headway in persuading the other. Also, I feel that I may have common ground with NoWheels; she firmly supports the reduction of speed and traffic volumes in residential areas whereas I support the raising of speeds where safe on suitable trunk routes. These might not be completely exclusive and (as summarised) I actually agree with NoWheels' view*.
Your comments seem to advocate the reduction of speeds generally and without qualification; after all if we slow down then accidents will be less serious. This view is, to me, only supportable with a plethora of qualifications; without these it is simplistic and naive. This is not intended to be a personal comment; you asked me to explain myself and I have explained how your posts have come across to me.
Last, we only see you in the speeding and cameras threads. This intrigues me. It makes me wonder how much driving you actually do. If you were a regular driver, I would have thought that other threads would also interest you. I am left wondering why not.
patently.
*NoWheels; I do not pretend that this is a complete summary. And I know it is not perfect. Can I apologise now, in advance?
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Shall we lighten things up a bit?
How about this, from the ABD website:
Height Kills
By Andrew Bent
The traffic engineer was quite pleased with himself, he had finally managed to stop the local bus drivers trying to take their double deckers under the low bridge under the railway, so Councillor Prescott might finally concede that he knew what he was doing. But as he entered Prescott's office he saw that the councillor was in an ominously thoughtful mood.
'I see we've had a reduction in accidents in Railway Terrace' said Mr Prescott, 'Yes' said the engineer, anxious to demonstrate his success, 'You see I did a survey and found that the maximum safe height under the bridge was 12'2", so I arranged for some warning signs to stop anyone taking a vehicle more than 12' high...'
But the Councillor had already lost interest. 'I've been studying some statistics' said the Councillor (the engineer winced, Councillor Prescott's grasp of mathematics was notoriously shaky) 'and it seems that when those new warning signs went up the average height of vehicles using Railway Terrace fell by 9 inches', 'Well, yes..' replied the engineer, 'and accidents dropped by 18%' continued the Councillor triumphantly'. The traffic engineer tried to figure out where this was leading, 'Do you realise what this means? Every inch of average height reduction leads to a 2% reduction in accidents! All we have to do is alter the warning signs to read 11' and accidents will drop by another 24%!'
His head spinning, the traffic engineer tried to reason with the Councillor, 'but if a 12 foot vehicle can get through perfectly safely, what is the point in imposing extra restrictions?' Councillor Prescott was having none of this, 'you don't seem to understand, Height Kills, if every inch of height reduction causes a 2% drop in accidents, surely we must have a height limit reduction program, let's speak to the bus company and see if they can lower the single deckers somehow.'
The traffic engineer thought quickly, there was no point in trying to explain the facts, Councillor Prescott always regarded knowledge of road traffic and accident causation a fatal disqualification for making decisions on the subject, but there was a possible way to turn the situation to advantage. 'There is another low bridge, under the disused railway in Beeching Close, where lorries do sometimes get stuck, but I haven't had the funds to tackle the problem before, I suggest that should be the first priority for the height reduction program'. Councillor Prescott agreed and the traffic engineer set off for Beeching Close with measuring rod in hand.
At first it wasn't clear why there was a problem at this particular bridge, there was already a height restriction of 7 feet, so why on earth were drivers ignoring it? After an examination of the bridge the reason became clear, the maximum safe height was over 14 feet. On receiving a recommendation that the 7 foot height limit was unrealistic and should be raised, Councillor Prescott was apoplectic, 'lorries are getting stuck because they are too high' he yelled, 'surely the limit needs to be lowered'. The engineer tried to point out that it was precisely because the limit was obviously ludicrous that it was being ignored, and that raising the limit would increase compliance, but the Councillor did not understand. 'In Railway Terrace, reducing the height reduced accidents, therefore Height Kills' he argued, 'surely raising the limit in Beeching Close will increase average heights, therefore increase accidents,' 'But it isn't the average height that matters' the engineer tried to point out, 'a 14 foot limit will be taken seriously and will reduce instances of excessive height, therefore reduce accidents, whether the average goes up or down is totally beside the point'. 'But Height Kills' bellowed the Councillor, 'no it doesn't' the engineer bellowed back, of course he should have said 'not necessarily' but this is not an easy thing to bellow.
'How can you say height didn't cause this?' Councillor Prescott produced a press photo of the mangled remains of a double decker wedged under the Railway Terrace bridge and dropped it on the desk with the air of one producing the ace of trumps. 'The point was that the height was excessive for the situation, it is excessive height that causes the problem, not height itself' the engineer protested, but the Councillor wasn't listening, 'I've already decided to introduce a height reduction program, reducing all existing height limits by a foot, if this succeeds in reducing heights, I'll introduce a host of new height limits, if it doesn't I'll reduce the limits further until it does....'
The engineer stopped listening; once Councillor Prescott had made up his mind, there was no point in giving him the facts.
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No wonder the ABD isn't taken very seriously by policy-makers!
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Admittedly it was in their humour section, and not (I think) meant seriously. Although I can see one policy-maker taking umbrage.
I shall say no more, to avoid commenting on a subject that I have now foresworn....
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Actually, aside from making the councillor look dumb (and who would believe that !) I think its an excellent explanation of why lowering speed limits beyond what is reasonable will cause people to ignore them and drive at a speed faster than they would have driven at had a sensible speed limit been set.
Surely only people with closed minds, a soapbox, and a fanatical campaigning mentality with tunnel vision would fail to see the relevance. Or do you disagree and think that even they could see the point ?
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Thank you Mark.
If I allowed myself to speak on this subject, that's roughly what I would say....
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I thought Patently's story was just too sad & close to the truth to be funny.
Last night, coming into London at around 11pm from the M11, the A12 was shut owing to an earlier accident. So A13 it was, which I avoid like the plague as it is a 3-lane dual-carriageway road. With admittedly some traffic cones, for reasons I have never managed to fathom.
And a 30mph speed limit. Either you go (almost) to sleep with complete boredom (try doing 30 along an empty 3-lane road) or you speed.
That speed limit does nothing whatsoever for safety, as the law-abiding citizens cease paying attention, and then this becomes very dangerous when those who are not law-abiding citizens zoom past at 60mph - having chosen a higher speed than they would have chosen had a sensible (say 50mph - or maybe 40) speed limit been in place.
All of us - the speeders & the 'slowers' can feel disadvantaged by this scenario. I'll leave you to guess what speed I was doing - I might tell you later if you're all nice to each other.
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Agree entirely, mapmaker. I have been frightened there before - when people are routinely double the limit you are put in a quandry.
It is also the reason why increasing the motorway speed limit from 70 to 80 would not necessarily increase everyone's speed by 10mph. My suspicion is that many who today are somewhere between 80 and 95 would slow to 80 if that made them legal. That could actually reduce average speeds. It would also make the idiots stand out a lot more - making the new limit easier to enforce.
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