Safe Speed Forums

Hi NDP,
I am currently in discussion with my MP about a speed camera being used near my home. I thought that most of the time the 85th percentile figure was the main guide . Do you know if this is the case ? If this figure is not used then how are speed limits arrived at ?

Regards

Richard

OK, but the point remains that your assuming that the speeding drivers up to the 85% are correct in their assessment of the appropriate speed.



No, we make ourselves safer drivers.

What cameras and limits do is provide a mechanism to deal with those who aren't driving safely.

I would imagine it is a consideration to be considered alongside the long list of other considerations

UHHH - Cameras and the overzealous use of limits provide a false idea that as long as we are not over the limit we are safe - when indeed the limit speed could be absolute suicide - for both driver and pedestrians -
we have a road past a school --wide enough for a row of parked cars on one side, a row of parked buses on the other and a single file of traffic between --at school going in /chucking out time, with a pedestrian crossing not so far away, cars disgorging kids all over and kids running accross the road. You tell me that 30 (as limit) is safe (or even possible ) at that time.

Now at 7.30 on Sunday morning - a few cars parked on one side - no kids no traffic --the 30 limit is safe , possibly to low. But i have seen a talivan "enforcing" at that time.

The problem is that the gospel according to St Pratnership says that in both cases 29MPH is safe.

In the first case a car could be doing 29 (safe says the scams) ---not speeding - where is the mechanism to deal with the excess speed - bring back PC Trafpol

_________________
lets bring sanity back to speed limits.
Drivers are like donkeys -they respond best to a carrot, not a stick .Road safety experts are like Asses - best kept covered up ,or sat on

The picture you have chosen for your example is one of a pair. The other one, which is not shown, has markings on it, which show that a pedestrian crossing passes over this stretch at exactly the spot from where the picture was taken. Funny that - the close proximity of a pedestrian crossing over this road somewhat weakens your case that the limit should be opened up here, doesn't it!

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I stole this .sig

Given that there are no properties whatsoever on the road, why does it need to be a 30 limit in the first place? There are plenty of 40 limits with Pelican crossings - I can even think of an NSL.

And why do we have to wait for about 300 yards travelling away from the crossing before the higher limit kicks in?



(my picture, btw)

On the A50 at Uttoxeter the Highways Agency have done something similar to protect a Pelican crossing, but it involves at 40 limit, not a 30, and is markedly shorter in extent.

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"Show me someone who says that they have never exceeded a speed limit, and I'll show you a liar, or a menace." (Austin Williams - Director, Transport Research Group)

Any views expressed in this post are personal opinions and may not represent the views of Safe Speed

Indeed, it is important that engineering and enforcement measures ensure the burben of responsibility is firmly on the drivers shoulders - however, this isn't compatible with limits being used as limits and being enforced as such.

The main failing of current policy is the simplistic message that is put out to explain why we have cameras and why we have limits, and why drivers should stick to them. Thats not easy to solve - its simply symptomatic of the age of the soundbite.



I didn't say cameras were *the* mechanism to deal with speed; rather, that they are *a* mechanism to deal with speed.

Except speed limits shouldn't (generally) be used to deal with an individual hazard (eg a signalised pedestrian crossing). The onus is on drivers to deal with hazards - they can expect to have their hand held, and anything that holds drivers hands is something that needs careful consideration.

I'd suggest that all that is needed here is a pair of warning signs (one on each side of the carriageway) to diag 543 (signals ahead), possibly with a distance plate to diag 572 if there is an issue with the distance to the crossing being disceptive. (I'd also suggest that even this is only necessary as the road appears to be a fast dual carriageway - not the place you'd expect to find signals).

If there is still a problem (if indeed there ever was one), then a red light camera would be the next step.

If there was still a problem (and I'd suggest that'd be pretty exceptional) then maybe a local speed limit, and I'd suggest that should be 40 and as tightly drawn as possible [though there are alot of things to consider, such as the siting of signs and "see through"]).

30 in this instance seems excessive and its hand holding which should not be indulged in (drivers will only come to expect it, and that is dangerous).

No - it actually means that less than 15% are driving too fast for the conditions. And hell, yes, I'm 100% certain of it.









Absolutely. But it doesn't matter. The figures are so vast that even gross errors would even begin to affect the conclusions. And I have an ace.

The median driver has FAR less than the average crash risk. Consider this graph:



With drivers sorted by crash risk it's immediately obvious that much of the risk is concentrated at the low quality end of the scale. I reckon 10% of drivers cause 60% of crashes.

We need to police well at the lower end of the scale. We need to encourage and train the rest - 80% say.



You might find a couple of funny accident black spots.



Except cameras don't - and do distort everyone's safety priorities - pushing a minor factor WAY up the scale where it doesn't belong.

Limits are useful so long as we don't get too obssessed with them. Remember 60% of drivers are 'speeding' on most road types according to DfT figures. Yet excessive speed crashes (which also include inappropriate speed within the speed limit) are a seriously rare. And when they do crop up it's more typically a hazard perception failure than a careless use of speed.

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

Unfortunately as far as the present government is concerned *a* = *the*

There is talk of a carrot and stick policy ---the carrot has withered and wilts having been kept in the dark too long, whilst the stick grows at the rate of the partnership empires.

_________________
lets bring sanity back to speed limits.
Drivers are like donkeys -they respond best to a carrot, not a stick .Road safety experts are like Asses - best kept covered up ,or sat on

Given the location, which I am familiar with, I would say a tightly drawn 40 would be appropriate, and would give a useful signal to drivers. The Pelican crossings are situated just on the exit from a roundabout.

When driving in the opposite direction, down the hill towards the crossing, the 30 limit must extend for at least 400 yards, and I would say is universally ignored apart from learners and IAM associates on observed runs. Although one IAM observer I spoke to said he deliberately avoided that road as he couldn't in all conscience expect his associates to adhere to the 30.

_________________
"Show me someone who says that they have never exceeded a speed limit, and I'll show you a liar, or a menace." (Austin Williams - Director, Transport Research Group)

Any views expressed in this post are personal opinions and may not represent the views of Safe Speed

Even if it is less that 15% of drivers, thats still alot of drivers.

And surely if you're assuming that 15% are driving too fast, then you are making an assumption which is even bolder than mine - that *at least* 85% of drivers are correct in the assessment of their speed.



On what grounds?




Even given the rather unscientific way in which the data is collected?



Whilst that chart seems somewhat arbitrary, it does at least appear plausible.



I don't disagree. Lets have the police assist with the education. Lets free up their time by having automated enforcement where practical.



Don't what? Provide a mechanism to deal with (at least some of) those who are driving dangerously?



Why? Its a limit - it isn't (or shouldn't be if limits are set properly) an attempt at telling the driver at what speed they should drive - thats still their responsibility. Its just a ceiling, thats it.



Thats based on accident records, which are often pretty dubious.



Indeed, but sometimes that hazard perception failure is due to the nature of the road cf something that the driver cannot detect, or where the nature of the road is misleading. Hence limits.

Theres also the issue of keeping consequences within acceptable limits, of course.

The problem with cameras and *genuinely* dangerous drivers is that all the camera does is take a photograph of the offender, if indeed it is live.

For example, consider two drivers - one driving an unregistered, uninsured vehicle at say, 65mph in a 30mph zone, and the other perfectly legal driver who is driving at 35mph in a 30mph zone.

In both cases, the camera will be activated and progress continues unabated. In the case of the former driver, the contribution to road safety is zero. In the case of the latter driver, the contribution is negative as they weren't doing anything unsafe, and may build an attitude of resentment when they get the £60/3 points.

Consider the effects if the camera was removed and police patrols were introduced. There is a considerably higher chance that the nutter will be caught and booked, while the safe driver will be allowed to continue.

Speed cameras in conjunction with the current placement guidelines and the associated depletion of Police officers on traffic patrol completely reverse the neccessary and vital priorities required to improve road safety in this country.

It's not rocket science, it's simple common sense. Something which has long disappeared from British society.

How is 'less than 15%' any number greater than zero? 15% is the absolute maximum. If asked to guess I'd give it about 3 or 4%. Yes, it's still a lot of drivers - around a million.



Nonsense. A good 20% of them are probably driving inappropriately slowly. I'd expect at least 60% to be 'wholly correct' in assessment of speed given their skills level and vehicle type.



Mostly grounds we have discussed.

Speeding is far more prevalent than speed related crashes.

Excessive speed crashes are rare.

Crashes, especially injury crashes are rare.

The bottom line is that if you're driving significantly too fast for the conditions it simply isn't possible to react to events and the risk of a crash rises very rapidly. And there's nowhere near enough of these crashes to indicate that normal experienced motorists are getting into this kind of trouble.

On the other side of the same coin we should look at the subsconscious risk assessment processes that drivers run all the time. When there's danger ahead they slow down. This is the essence of the driving process.

And when you do look at crash causes, carelessness and inattention at right there at the top of the list, probably accounting for more than 80% of all crashes.



I hear this sort of claim a lot. While I agree that there are problems it usually arises because the facts don't fit the framework of ideas. That's no surprise to me, because the framework of ideas being applied nationally is WAY out. 'Totally divorced from reality' would sum it up.

The fact that crash causation data tends to self-similarity lends considerable credence to the idea that it's actually correct too.



We went there yesterday. Would you be happy if we kept child pedestrian fatalities to the 10% expected at 20mph impacts? (I note that the latest DfT re-interpretation of the data puts the 20mph fatality percentage at 2.5% - but that's more than 6 times worse than the figure we're achieving in 30 and 40mph speed limits with ~60% speeding.)

Bottom line: Sticking to the speed limit WON'T stop you crashing and it WON'T reduce crash severity. More work on 'appropriate speed' and hazard perception will. More work on skills and attitudes will. Proper roads policing (targeting the risky) will.

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

If you view speed cameras in the same way as drugs or medication, (a treatment for a problem) then the anology with medicine becomes interesting. Pharma companies have to rigorously test their products, carry out trials -usually randomised controlled trials. Essentially the benefit must outweigh the cost and be based in sound science).

I'm concerned that the potential side-effects of cameras, (many have been proposed including diverted attention from the road, panic braking, placing a simplistic focus on speed v safety) have never really been assessed.

The bottom line is that if speed cameras were a drug, they wouldn't be prescribed until we had a clearer picture of their effects.

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"Not everything that counts can be counted, and not everything that can be counted counts."

Damn right. It's this aspect of the whole thing that makes me the most angry about it. I mean... How DARE they risk our lives like that? Especially when they are wrong.

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

The picture gives the wrong impression that there are no pedestrians around atall. It's the constant spin that gets you.

_________________
I stole this .sig

So we're agreed - its a lot of drivers.



Nonsense. A good 20% of them are probably driving inappropriately slowly.[/quote]

"Inappropriately slowly"? Would you care to define this?



I'd expect people to be able to spot a diamond-grade-backed camera and drive past it at below the speed limit - yet so many fail at this simply task. If drivers are choosing an appropriate speed




Mostly grounds we have discussed.

Speeding is far more prevalent than speed related crashes.

Excessive speed crashes are rare.[/quote]

But this is all based on accident stastics, and the assumption that a factor is not cited by a reporting officer then that factor certainly wasn't a factor. This is deeply flawed.



Indeed. Doesn't mean we shouldn't do anything about crashes.

Ditto speed related crashes (even if they are as rare as you claim)



I don't think anyone disputes this.



But again, this is based on treating accident reports as gospel, as opposed to what they really are.



No, they slow down when they *perceive* there to be a danger to *them* ahead. Where they fail to consider others, or fail to perceive a hazard, then they can't hope to set their speed accordingly. This isn't incompetance, its simply human fallibility - hence we have limits to act as ceilings to cover for this scenario.



We've done this - accidents aren't caused, they are arrived that from a set of circumstances.




Does this include inattention to their speed and/or the speed limit?



"Probably"?




I'm sure the fact that accident records are usually simply the opinion of what the attending officer can confidently say was involved. And usually nothing more scientific.



We went there yesterday. Would you be happy if we kept child pedestrian fatalities to the 10% expected at 20mph impacts? (I note that the latest DfT re-interpretation of the data puts the 20mph fatality percentage at 2.5% - but that's more than 6 times worse than the figure we're achieving in 30 and 40mph speed limits with ~60% speeding.)[/quote]

So whats your solution? And how will it deal with the child who runs out at the last minute (and they will, they don't know better).



No one is saying it will - but it reduces the risk.



No it won't, it'll simply reduce the risk.



No it won't, it'll simply reduce the risk.

Ah, so when a driver panic brakes for a speed camera (illustrating gross incompetance in doing so) - its the government's fault.

And yet you whinge when the goverment feels the need to play nanny?

How do you know the impression that picture conveys is wrong? And of what relevance is it to what has been discussed here?