Safe Speed Forums

If a tree is going to fall on my doorstep at some random point in the next hour, then if I spend 15 minutes stood on my door step there is a 1 in 4 chance of it hitting me. If I spend 30 minutes stood there then the odds increase to 1 in 2.

This is why if we can see the tree creaking and is clearly "going to go at any minute" we don't walk sedately under it, we bloody well run!

No doubt you will argue that you shouldn't walk under it at all, but in relation to the current debate that is like saying we shouldn't drive, ever. When we climb into a car we accept a level of risk of all sorts of nasty things happening, whether we like it or not. The job from then on is simply to minimise that risk, and minimising the degree of exposure is a perfectly valid method, even if it isn't politically correct to say so.

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CSCP Latin for beginners...
Ticketo ergo sum : I scam therefore I am!

minimise the risk of losing your license (a hazard to the driver) by trying at all times to remain within the speed limit.

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COAST Not just somewhere to keep a beach.

A young loner on a crusade to champion the cause of the innocent, the helpless, the powerless, in a world of criminals who operate above the law.

That has nothing to do with the topic.

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CSCP Latin for beginners...
Ticketo ergo sum : I scam therefore I am!

I think it does - the risk of losing your license is one that faces all drivers on the road today. It should be factored in to every risk analysis that the driver carries out.

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COAST Not just somewhere to keep a beach.

A young loner on a crusade to champion the cause of the innocent, the helpless, the powerless, in a world of criminals who operate above the law.

But that is a problem isn't it - letting concentration time be spent on things that don't actually impact on real-world risk, means that the mitigation options against those real world risks is reduced. People spend time worrying about loosing their licence and watching their speedo rather than concentrating on the real risks out there, and the real-world risk goes up - more accidents, and they are caused by this artificial threat.

That's unkind!

To be fair to Handy, his original assertion re kinetic energy is perfectly correct - it's basic physics. However, the debate that has followed, and the "confounding factors" that have been introduced, have served to highlight the essential futility of a purely one-dimensional approach to road safety.

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"Politicians are the same the world over... We build bridges where there aren't any rivers." - Nikita Kruschev

Kinetic energy is largely irrelevant anyway.
The only kinetic energy which is relevant is that part which is dissipated in, and by, the collision.
Let's say, for argument's sake, that a 80kg pedestrian is hit by a 1600kg van with a flat, unyielding, front-end. The only kinetic energy dissipated in, and by, the collision is that part required to accelerate the pedestrian up to the speed of the van - which is roughly 80/1600, or 5% of the kinetic energy of the van immediately prior to the collision. So, after the collision, the van still possesses 95% of its pre-collision kinetic energy, and will, as a result, only have lost about 2.2% of its speed.
In reality though, a proportion of the total dissipated energy will go into deforming the body panels etc.
Also, in pedestrian collisions, what usually happens is that the the pedestrian is somersaulted over the bonnet, or rolls off sideways, is struck a glancing blow, etc - which further reduces the amount of energy actually dissipated.
And, as the exact mechanics of the collision are random, the actual amount of energy going into the pedestrian can vary hugely - by very much more than the difference in total energy which a few mph gives.

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

That's quite funny, but probably ill judged. It takes a brave soul to challenge our arguments these days, and poor handy has been jumped on comprehensively - largely with sound rational arguments.

It might also be wise to remember that many important and influential people - including the government - have fallen for the 'it's simple physics' approach to road safety. In reality, on this point, we have the minority view except in this particular environment.

I'd hate to think that we do anything here to discourage alternative views or fair debate.

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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

I think you have highlighted something significant, however the speed of impact still has the same relationship to damage and kinetic energy that was previously assumed.

This is because the energy that counts in the nice simple example is that acquired by the pedestrian. It still has the same previously assumed relatioinship to impact speed. The ONLY error was to suggest that the vehicle's kinetic energy was 'the factor' to consider.

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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

Absolutely Rewolf. This is truly a vital component that must be considered whenever we introduce 'artificial hazards' into the environment. Everyone has less time left for real hazards.

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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

Sorry, I'm just not the kind of person to call a spade a manually operated digging instrument.

Im my opinion, handy has realised he was wrong with his original statement and is no9w dragging the discussion off at a pointless tangent with comments such as...


Far from trying to stifle debate I an trying to bring things to a halt before he loses what little credibility he still has.

Oh. Grow. Up.

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COAST Not just somewhere to keep a beach.

A young loner on a crusade to champion the cause of the innocent, the helpless, the powerless, in a world of criminals who operate above the law.

your opinion is flawed - the title of the thread, the point of the debate, was about the FACT (agreed by several posters) that there is more energy to dissipate in a faster collision than a slower one. POINT TO THE POST WHERE THIS HAS BEEN DISPROVED.

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COAST Not just somewhere to keep a beach.

A young loner on a crusade to champion the cause of the innocent, the helpless, the powerless, in a world of criminals who operate above the law.

I haven't said - anywhere - that kinetic energy was the only one to consider, except as in this hypothetical comparison where ALL OTHER THINGS (such as the potential likelihood of a collision - a deduction based on safespeeds claims) REMAIN EQUAL.

I have never denied that in the real world all other things are not equal.

I even agree - mostly - with the safety elements of the messages here, and that policy is generally overweighted towards a single issue.

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COAST Not just somewhere to keep a beach.

A young loner on a crusade to champion the cause of the innocent, the helpless, the powerless, in a world of criminals who operate above the law.

I debate, you resort to playground level name calling, yet you feel I am the one at risk of losing credibility.

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COAST Not just somewhere to keep a beach.

A young loner on a crusade to champion the cause of the innocent, the helpless, the powerless, in a world of criminals who operate above the law.

Four posts in a row!

You may have missed the point of my reply to Pete - which was effectively to dismiss his particular dismissal of your position.

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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

Indeed they do, regularly! I'd say that the west side of the M25 (unless those roadworks have been removed in the last 6 months) has more collisions at 5-10 mph than any other stretch of road, simply because everyone is bored stupid and not paying attention.

Personally I think Homer was using humour in a fairly friendly way in your interests. However I saw the opportunity for offence and issued a gentle reminder.

I'd like to call a halt to that particular line of discussion, unless anyone wishes to issue an apology to anyone else.

If anyone feels that they must continue, then please do so by email or PM.

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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