Speeding Does Not Cause Accidents

[singlecoil]

Mill Wheel said:

I approve of speed limits that are set with safety in mind - not safety perceived by a council who are cowed by the likes of BRAKE into doing something about accidents that may or are not related to speed.

I expect you will find that the majority of speed limits are set with safety in mind, the problem for you is that you disagree with most of them, and therefore have decided that they are not set with safety in mind.

[Moonhawk]

A few days ago I fired off an email to my local council.

In my local area speed limits have been dropping like flies. The council claims to use the government white paper to set speed limits. That white paper clearly states that setting local limits should be "evidence led" - so I asked the council what evidence they had that the limits needed changing or what evidence they had that the new lower limits had been effective in improving road safety.

The reply that came back was:

"Most of the speed reductions that have been put in place have been done so after requested from residents"

Doesn't sound very "evidence led" to me

[irocfan]

singlecoil said:

irocfan said:

singlecoil said:

irocfan said:

well for the BRAKE contributors on here here is the logical conclusion to your arguments...

The old appeal to ridicule, always an argument winner as far as the 'go faster' brigade are concerned. Trouble is, it doesn't work on anyone else.

not at all - it's just the logical conclusion of some of the 'speed kills' fkwittery spewed on here. A road which has seen no accidents as an NSL is reduced to a 40 and suddenly you're going to crash and burn because you're doing 45? Please! Yes you're breaking the law but that's it

Yes at all- and now you are adding straw man to the ridicule. I daresay your nonsense will go down well with those already to converted to your cause (whatever that is) but no-one else is going to take any notice.

oh the great know it all has spoken - let us all listen to his words of wisdom

Edited by irocfan on Thursday 23 October 14:37

[Moonhawk]

singlecoil said:

Yes at all- and now you are adding straw man to the ridicule. I daresay your nonsense will go down well with those already to converted to your cause (whatever that is) but no-one else is going to take any notice.

To be fair - it is the logical conclusion to the argument.

The "speed kills" mantra is unqualified and open ended. We are all aware that all else being equal, the greater the speed of a collision, the greater the potential for damage.

The problem with this argument however is that it is true at all speed. We may reduce the speed from 60 to 50 and observe that there is commensurate reduction in deaths/injury for any accidents that occur - however we have not reduced the risk to zero - and since nobody is willing to put a figure on just what level of risk is acceptable - the "lower speed lowers risk" argument still applies.

If the speed is reduced further (say to 40) - the casualty/injury rate in any accidents will also drop further - but again, still not to zero. Do we continue to reduce it further over time, to 30, 20, 10 in the pursuit of decreasing the risk further? At what point do we stop reducing limits due to the law of diminishing returns and focus on other areas of road safety that may give better results.

You may think people are being facetious - but unless we put lower bounds on what is considered an acceptable level of risk - you can't assess whether a balance has been struck between risk and usability.

This is nothing to do with converting anyone to a cause. By all means formulate an argument as to why limits should be reduced on any particular road - but you should be prepared to qualify that argument.

[Jon1967x]

johnao said:

Jon1967x said:

You really don't get it do you. You go round a blind bend and find an obstacle in the road causing you to stop. If your are travelling faster you have less time because it's the distance on the road that's fixed. That's not to say you can't stop, you might, but then you might not.

No, I'm afraid it's you that doesn't get it.

The mantra of "speed kills" is naive at best and misleading at worst.

In your example of driving around a "blind" bend it's not the absolute speed that's the issue, it's whether or not the driver is able to stop on his side of the road in the distance seen to be clear. The safe speed is therefore determined by the vision available. If you can stop in the distance seen to be clear, you'll be able to stop; if you can't, you won't, and you'll crash. See, it's really very simple and doesn't depend on speed limits or any other exhortants to slow down.

The safe speed through your "blind" bend [now there's an emotive description if ever there was one, very few bends are "blind"] is maybe 5mph, 10mph, 15mph, who knows? The only way to judge the correct, safe speed is...

"CAN I STOP ON MY SIDE OF THE ROAD IN THE DISTANCE SEEN TO BE CLEAR"

I suggest that if you're going to join an argument then at least have the courtesy to understand the point being argued. I actually agree with most of your points but not all.

I don't agree that the opposite of the "speed kills mantra" is that speed doesn't kill. There are 2 sets of evidence posted that shows scientific research that speed is a significant but not sole factor.

Back to the point, from Phatboy rambling arguments, the best I can make out is he maintains that time is more important than speed, and speed does not reduce the reaction time, to the extent that in a similar thread to this he says it can be argued that driving faster past a point on the road reduces your likelihood of an accident because you spend less time driving past it. He's also argued that if you driver faster you wouldn't be on that point of the road when a car might pull out because you'd have been past it already. If you subscribe to these kind of arguments then carry on.

[blueg33]

v12Legs said:

I'd have a bit more sympathy with the anti-speed limit argument if there was any evidence that drivers tended to only break the "unnecessary" or "illogical" speed limits. I see people blasting through densely populated urban areas at well over 30 all the time.

The fact is, a lot of drivers are incapable of assessing a safe speed to travel at, and traffic police cannot be everywhere, so speed cameras are a useful tool to catch people so stupid and/or unobservant that they cannot match their speed to the clearly posted legal limit.

Obviously the residents of PH are far superior to the average driver, and can safely drive any road at 100mph or more, but unfortunately we have to make laws to protect people from the crap average driver.

What is "well over 30mph"? Is say 36mph "blasting"?

I would rather people were looking at the roade and other drivers than trying to spot cameras and slamming on the brakes at the last minute

[v12Legs]

blueg33 said:

What is "well over 30mph"? Is say 36mph "blasting"?

I would rather people were looking at the roade and other drivers than trying to spot cameras and slamming on the brakes at the last minute

Through a town, yes I'd say 36mph is "blasting"

I'd rather people drove carefully and within the law; then they wouldn't be trying to spot cameras in the first place and would rarely have a requirement to slam their brakes on at the last minute.

[Jon1967x]

Moonhawk said:

singlecoil said:

Yes at all- and now you are adding straw man to the ridicule. I daresay your nonsense will go down well with those already to converted to your cause (whatever that is) but no-one else is going to take any notice.

To be fair - it is the logical conclusion to the argument.

The "speed kills" mantra is unqualified and open ended. We are all aware that all else being equal, the greater the speed of a collision, the greater the potential for damage.

The problem with this argument however is that it is true at all speed. We may reduce the speed from 60 to 50 and observe that there is commensurate reduction in deaths/injury for any accidents that occur - however we have not reduced the risk to zero - and since nobody is willing to put a figure on just what level of risk is acceptable - the "lower speed lowers risk" argument still applies.

If the speed is reduced further (say to 40) - the casualty/injury rate in any accidents will also drop further - but again, still not to zero. Do we continue to reduce it further over time, to 30, 20, 10 in the pursuit of decreasing the risk further? At what point do we stop reducing limits due to the law of diminishing returns and focus on other areas of road safety that may give better results.

You may think people are being facetious - but unless we put lower bounds on what is considered an acceptable level of risk - you can't assess whether a balance has been struck between risk and usability.

This is nothing to do with converting anyone to a cause. By all means formulate an argument as to why limits should be reduced on any particular road - but you should be prepared to qualify that argument.

It depends on whether you are trying to eliminate accidents or serous injury and death. Its reasonably well known that a pedestrian being hit at 20mph has a pretty high likelihood of survival, hence the 20 is plenty past schools and there's no real logic to decrease further. Equally car on car accident statistics show a higher speed is survivable. The charts in the US paper I linked to, while now showing a little age, show that there is an inflexion point about which the outcome becomes significantly worse at a given speed - I think it was around 70 kph (lets call it 50 mph near enough). Roads with a high chance of head on accidents have 30 limits equating to a 60 mph closing speed - not so far away from the threshold - and roads with less chance of a closing impact (motorways and country roads where you can end up hitting a tractor or grass bank) are 60/70 mph - not so far away from the scientific evidence on survival speeds. Country lanes with NSL have the highest fatality rates and its easy to see why - when you do have a head on the closing speed is significant.

Back to "speed kills" mantra - from factors that cause an accident its only part of the problem and significantly less than Brake etc would have you believe but the evidence does suggest that a lower speed limit does reduce the number of accidents. From a survival perspective it's a much more significant factor (and for the pendants its the deceleration from speed that counts as we're all travelling through the universe at a thousand miles a second and its not killed any of us yet).

Is this really so hard to understand?

[Moonhawk]

Jon1967x said:

It depends on whether you are trying to eliminate accidents or serous injury and death. Its reasonably well known that a pedestrian being hit at 20mph has a pretty high likelihood of survival, hence the 20 is plenty past schools and there's no real logic to decrease further.

And therein lies exactly the problem I was highlighting - whilst 20mph does give a high probability of surviving an accident - the probability of dying is still non zero and since nobody is willing to quantify just what constitutes an acceptable level of risk - the "speed kills" mantra can still be invoked.

You say there is "no logic" in reducing a 20mph limit further (presumably because the law of diminishing returns applies) - yet there are calls to do exactly that:

http://www.standard.co.uk/news/transport/driverles...

[blueg33]

v12Legs said:

blueg33 said:

What is "well over 30mph"? Is say 36mph "blasting"?

I would rather people were looking at the roade and other drivers than trying to spot cameras and slamming on the brakes at the last minute

Through a town, yes I'd say 36mph is "blasting"

I'd rather people drove carefully and within the law; then they wouldn't be trying to spot cameras in the first place and would rarely have a requirement to slam their brakes on at the last minute.

There are plenty of urban speed limits set at 40mph, legal blasting? IMO to define blasting you would need to look at many factors other than the speed limit, like conditiona, road layout, time of day etc.

Have you seen the number of people who are travelling below the limit and still slam their brakes on for cameras? - its rife.

[Jon1967x]

Moonhawk said:

Jon1967x said:

It depends on whether you are trying to eliminate accidents or serous injury and death. Its reasonably well known that a pedestrian being hit at 20mph has a pretty high likelihood of survival, hence the 20 is plenty past schools and there's no real logic to decrease further.

And therein lies exactly the problem I was highlighting - whilst 20mph does give a high probability of surviving an accident - the probability of dying is still non zero and since nobody is willing to quantify just what constitutes an acceptable level of risk - the "speed kills" mantra can still be invoked.

You say there is "no logic" in reducing a 20mph limit further (presumably because the law of diminishing returns applies) - yet there are calls to do exactly that:

http://www.standard.co.uk/news/transport/driverles...

Madness - I take your point.

And jokingly, 10 mph would probably be an increase in average speed there

[robinessex]

emmaT2014 said

An increase in speed of traffic above the posted limit causes the rate and hence the risk of collisions to increase; the relationship has been established to be a square-law.

blueg33 said

I would be interested to see the source regarding the sqaure law and increase in accident rates.

emmaT2014 said

I’m sure you would, there are many of them. If you are not aware of them then it is not a surprise that you are making the statements you are and making elementary mistakes.

Yes, I'd be interested to see them as well. Save me the bother of looking. See this though:-

http://www.abd.org.uk/onemph.htm
http://www.abd.org.uk/trl511.htm
http://www.abd.org.uk/one_third.htm
http://www.ibiblio.org/rdu/sl-irrel.html

And that assumption would make our motorways the most dangerous roads. Er, but they're not. Per vehicle mile, they are the safest. Maybe you could describe a typical accident that is caused by speed, that a reduction in speed would have prevented it. I can only think of 1, and it's basically irelevent to the argument.

Edited by robinessex on Thursday 23 October 16:13

Edited by robinessex on Thursday 23 October 16:14

Edited by robinessex on Thursday 23 October 16:15

[irocfan]

robinessex said:

emmaT2014 said

An increase in speed of traffic above the posted limit causes the rate and hence the risk of collisions to increase; the relationship has been established to be a square-law.

blueg33 said

I would be interested to see the source regarding the sqaure law and increase in accident rates.

emmaT2014 said

I’m sure you would, there are many of them. If you are not aware of them then it is not a surprise that you are making the statements you are and making elementary mistakes.

Yes, I'd be interested to see them as well. Save me the bother of looking. See this though:-

http://www.abd.org.uk/onemph.htm
http://www.abd.org.uk/trl511.htm
http://www.abd.org.uk/one_third.htm
http://www.ibiblio.org/rdu/sl-irrel.html

And that assumption would make our motorways the most dangerous roads. Er, but they're not. Per vehicle mile, they are the safest. Maybe you could describe a typical accident that is caused by speed, that a reduction in speed would have prevented it. I can only think of 1, and it's basically irelevent to the argument.

I'd leave it mate - there's no arguing with fanatics

[robinessex]

irocfan said:

robinessex said:

emmaT2014 said

An increase in speed of traffic above the posted limit causes the rate and hence the risk of collisions to increase; the relationship has been established to be a square-law.

blueg33 said

I would be interested to see the source regarding the sqaure law and increase in accident rates.

emmaT2014 said

I’m sure you would, there are many of them. If you are not aware of them then it is not a surprise that you are making the statements you are and making elementary mistakes.

Yes, I'd be interested to see them as well. Save me the bother of looking. See this though:-

http://www.abd.org.uk/onemph.htm
http://www.abd.org.uk/trl511.htm
http://www.abd.org.uk/one_third.htm
http://www.ibiblio.org/rdu/sl-irrel.html

And that assumption would make our motorways the most dangerous roads. Er, but they're not. Per vehicle mile, they are the safest. Maybe you could describe a typical accident that is caused by speed, that a reduction in speed would have prevented it. I can only think of 1, and it's basically irelevent to the argument.

I'd leave it mate - there's no arguing with fanatics

Agreed !!

[singlecoil]

irocfan said:

oh the great know it all has spoken - let us all listen to his words of wisdom

Edited by irocfan on Thursday 23 October 14:37

Now you are just being childish.

[singlecoil]

Moonhawk said:

singlecoil said:

Yes at all- and now you are adding straw man to the ridicule. I daresay your nonsense will go down well with those already to converted to your cause (whatever that is) but no-one else is going to take any notice.

To be fair - it is the logical conclusion to the argument. etc. etc.

Speed kills isn't an argument, is a two word rallying cry, slogan, sound bite, what have you. No-one here is using it, except the anti-speed-limit campaigners in a continuation of their straw man argument.

The rest of us are trying to discuss this interesting subject sensibly. If you wish to do so too, I suggest you stick to what the people here are saying, not what pressure groups who are not part of this discussion are saying.

[johnao]

Jon1967x said:

I suggest that if you're going to join an argument then at least have the courtesy to understand the point being argued. I actually agree with most of your points but not all.

I fully appreciate the arguments and points being put forward.

Jon1967x said:

I don't agree that the opposite of the "speed kills mantra" is that speed doesn't kill. There are 2 sets of evidence posted that shows scientific research that speed is a significant but not sole factor.

Please do me the courtesy of not misrepresenting what I posted. I have never suggested..."that the opposite of the "speed kills mantra" is that speed doesn't kill". What I said was...The mantra of "speed kills" is naive at best and misleading at worst. I then went on to explain my understanding of the major cause of accidents, viz. the inability to stop on your side of the road in the distance seen to be clear. And went on to assert... If you can stop in the distance seen to be clear, you'll be able to stop; if you can't, you won't, and you'll crash... and doesn't depend on speed limits or any other exhortations to slow down.

I would be grateful if you would address this particular point rather than referring me to... "Phatboy['s] rambling arguments"

Jon1967x said:

Back to the point, from Phatboy rambling arguments, the best I can make out is he maintains that time is more important than speed, and speed does not reduce the reaction time, to the extent that in a similar thread to this he says it can be argued that driving faster past a point on the road reduces your likelihood of an accident because you spend less time driving past it. He's also argued that if you driver faster you wouldn't be on that point of the road when a car might pull out because you'd have been past it already. If you subscribe to these kind of arguments then carry on.

In the light of my assertion that the matching of speed and vision at all times is the fundamental principle in avoiding collisions, I don't really think any of the above quoted paragraph is relevant to either countering, or supporting, my argument. A cursory glance at the above noted paragraph and it's quite clear that nobody would consider the arguments posited on either side as being worthy of wasting time in debating.

[Guybrush]

At 20mph, pedestrians wanting to cross the road are more likely to step into the road and attempt to dash across between moving traffic than if vehicles were moving faster; plus, driving so slowly will reduce drivers' concentration levels.

[Moonhawk]

singlecoil said:

Speed kills isn't an argument, is a two word rallying cry, slogan, sound bite, what have you. No-one here is using it, except the anti-speed-limit campaigners in a continuation of their straw man argument.

The rest of us are trying to discuss this interesting subject sensibly. If you wish to do so too, I suggest you stick to what the people here are saying, not what pressure groups who are not part of this discussion are saying.

In that case why pick out one line of my post (which incidentally doesn't even contain the phrase "speed kills") rather than discussing the points I raised.

The "argument" I was referring to was the one which goes down the line of arguing that lowering speed limits lowers the risk of death or serious injury. Whilst that fact is patently obvious (you cannae change the laws of physics afterall) - the argument is always used unbounded and unqualified.

If we want to lower the risk of death or serious injury - what do we want to lower it to (or by how much)? What is an acceptable fatality rate on the roads, bearing in mind that we have to maintain a workable road transport network. Why isn't the current fatality rate, which is amongst the lowest in the world, the lowest at any point in the UKs history and still dropping (due in no small part to the massive advances in car safety technology) - already acceptable?

Are there other things we could be doing which would have a greater impact on the fatality rate, whilst at the same time having a lesser impact on the road transport network (e.g. highway code education on the national curriculum).

[Moonhawk]

Guybrush said:

At 20mph, pedestrians wanting to cross the road are more likely to step into the road and attempt to dash across between moving traffic than if vehicles were moving faster; plus, driving so slowly will reduce drivers' concentration levels.

Perhaps more education of pedestrians is in order, perhaps even holding them to account to a greater extent for breaches of the highway code (do we need a Jaywalking law?)

The DFTs own statistics show that in 21% of fatal accidents involving pedestrians - the pedestrians own actions is the major causal factor. Pedestrians "failed to look properly" has the same percentage of casualties as "exceeding the speed limit" does at 12% - yet nowhere near as much time/effort or money is thrown at that causal factor as is thrown at speeding.

(pages 189/190)

https://www.gov.uk/government/uploads/system/uploa...