80 mph speed limit proposal

Steady rider
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80 mph speed limit proposal

Postby Steady rider » 29 Sep 2011, 7:26pm

http://www.guardian.co.uk/world/2011/se ... sfeed=true

It seems like the DfT should read a DfT report, 'New Direction in Speed Management' March 2000.
http://www.securite-routiere.org/docacr ... ne2001.pdf
page 26/49 section 162

It details all the negative aspects of speed, higher accident risk and high pollution.

The UK has achieved a good road safety record by international standards (with the exception of cyclists) and now could be heading in the wrong direction.

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squeaker
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Re: 80 mph speed limit proposal

Postby squeaker » 30 Sep 2011, 9:09am

what was that about 'the greenest government ever' :roll:
"42"

Mike Sales
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Re: 80 mph speed limit proposal

Postby Mike Sales » 30 Sep 2011, 10:51am

Its interesting that Philip Hammond, the Transport Secretary, uses the argument that cars are safer these days, and fewer people are killed. This is explicit Risk Compensation. Why not accept the safety benefit and leave the limit in place? It seems that he thinks that we have overshot the target risk and should use up the benefit as a performance bonus.
I have only recently learned to drive, and seldom use motorways and I see myself as a cyclist, so that I don't particularly care what drivers do to each other on motorways. The other part of the proposal is less publicised.This is a suggestion of more 20mph. limits, and I would welcome it. I wish I could believe that it will happen. It is probably a feint to soften up the road safety lobby.

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Re: 80 mph speed limit proposal

Postby snibgo » 30 Sep 2011, 11:40am

The more recent TRL report, PPR397, reckons increasing motorway speed limits to 80 mph would increase annual fatalities by 18, serious by 64 and slight by 363, but would overall save £1250.9m over ten years (mostly due to time-saving).

I suppose Philip Hammond is happy with this calculation: 80mph will kill people, but the time-savings make it worthwhile.

Regarding 20mph limits: last I heard, central government were washing their hands of them. It isn't quid pro quo. Hammond is pandering to motorists' desire for speed, even if it kills some of them.

karlt
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Re: 80 mph speed limit proposal

Postby karlt » 30 Sep 2011, 11:51am

snibgo wrote:The more recent TRL report, PPR397, reckons increasing motorway speed limits to 80 mph would increase annual fatalities by 18, serious by 64 and slight by 363, but would overall save £1250.9m over ten years (mostly due to time-saving).

I suppose Philip Hammond is happy with this calculation: 80mph will kill people, but the time-savings make it worthwhile.

Regarding 20mph limits: last I heard, central government were washing their hands of them. It isn't quid pro quo. Hammond is pandering to motorists' desire for speed, even if it kills some of them.


Values are put on lives all the time in evaluating potential safety measures - I understand in rail it's around 1.6million. The above calculation appears to be 180 fatalities over 10 years, saving £1250.9 - that's 7 million per life. Compared with rail safety policies, that calculation argues for raising the limit. One can of course argue that lives are of infinite value, but if one does use that argument to inform policy to its logical conclusion, one will end up with a speed limit of around 5mph. At some point you are going to actually have to say "this measure will save lives, but will cost so much it can't be done." In effect, policy makers are forced to put a value on where the break-even point between improving safety and cost lies.

For my money, I'd be willing to go with an increase if it comes with enforcement. The net effect of that would actually be a speed decrease for some of the morons on the network ;). I don't think you'd then get the savings in time (and therefore money) because actually most of the buggers are flying along at 85 already, and plenty above that, so raising the limit will only speed them up if it actually means they can go at 95. Including enforcement of a new limit however may return road safety benefits because it will reduce speed differentials - the current situation of people like me sticking to the limit being flown past by people at 95 - 25mph speed differential will be replaced by people like me still going at 70 because I don't want to burn more petrol being overtaken by people doing 85 (because there'll always be some margin) - a 15mph speed differential.

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Re: 80 mph speed limit proposal

Postby snibgo » 30 Sep 2011, 12:06pm

karlt wrote:Values are put on lives all the time in evaluating potential safety measures - I understand in rail it's around 1.6million. The above calculation appears to be 180 fatalities over 10 years, saving £1250.9 - that's 7 million per life.

No.

£1250.9m is the overall projected saving, after doing the arithmetic, not the cost of each life (and other casualties).

I realise that politicians have to make difficult decisions, and I can see they have problems with "Doing X would save lives but is too expensive."

To me, this is different type of decision. It is, "More people will die so we can save money."

Of course, this is a political decision. Many people will agree with it. I can't argue that is is wrong in an absolute sense. But, to me, it's wrong.

karlt
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Re: 80 mph speed limit proposal

Postby karlt » 30 Sep 2011, 12:12pm

snibgo wrote:
karlt wrote:Values are put on lives all the time in evaluating potential safety measures - I understand in rail it's around 1.6million. The above calculation appears to be 180 fatalities over 10 years, saving £1250.9 - that's 7 million per life.

No.

£1250.9m is the overall projected saving, after doing the arithmetic, not the cost of each life (and other casualties).

I realise that politicians have to make difficult decisions, and I can see they have problems with "Doing X would save lives but is too expensive."

To me, this is different type of decision. It is, "More people will die so we can save money."

Of course, this is a political decision. Many people will agree with it. I can't argue that is is wrong in an absolute sense. But, to me, it's wrong.


But "More people will die so we can save money" is simply the inverse of "Fewer people will die but it will cost money." One could argue that we are currently "Doing X would save lives but is too expensive" - Hammond's argument presumably is that "Limiting cars to 70mph on motorways saves lives but it is too expensive so we'll have to stop doing it."

I am aware that that £1250.9 is the projected saving. That's why I divided it by the number of lives it would allegedly cost to reach the figure of around 7 million.

But it's all [rude word removed] anyway. The calculations are based on the assumptions that everyone currently drives at 70mph and if the limit's raised everyone will drive at 80mph. These assumptions are clearly flawed.

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Re: 80 mph speed limit proposal

Postby snibgo » 30 Sep 2011, 12:29pm

karlt wrote:The calculations are based on the assumptions that everyone currently drives at 70mph ...

No it isn't.

karlt wrote:...and if the limit's raised everyone will drive at 80mph.

That's correct.

I can see your point that "... "More people will die so we can save money" is simply the inverse of "Fewer people will die but it will cost money."", but to me they are morally different. I would have more respect for Hammond if he was upfront and said, "Look, Great Britain plc will save £7m for each person we kill, so let's do it."

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Re: 80 mph speed limit proposal

Postby PW » 30 Sep 2011, 12:31pm

It won't kill enough motons to make our lives any better so why bother! :twisted:
If at first you don't succeed - cheat!!

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Re: 80 mph speed limit proposal

Postby flat tyre » 30 Sep 2011, 12:45pm

The statement on the news this morning, attributed to Hammond was that the saving in journey time will benefit the economy. This is a completely fatuous statement! What saving in journey time? I have on odd occassions travelled from Hampshire to Scotland of North England and the opportunities to travel at 80 mph on our motorways are severely limited by the volume of traffic, so unless you're travelling in the middle of the night there is very little possibility of decreasing journey times. Do the maths and you will see that a 400 mile journey at 80 takes 5 hours whereas at 70 takes 5 hours 43 mins, but of course in practice the actual time saving will be far less.

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Re: 80 mph speed limit proposal

Postby karlt » 30 Sep 2011, 1:06pm

flat tyre wrote:The statement on the news this morning, attributed to Hammond was that the saving in journey time will benefit the economy. This is a completely fatuous statement! What saving in journey time? I have on odd occassions travelled from Hampshire to Scotland of North England and the opportunities to travel at 80 mph on our motorways are severely limited by the volume of traffic, so unless you're travelling in the middle of the night there is very little possibility of decreasing journey times. Do the maths and you will see that a 400 mile journey at 80 takes 5 hours whereas at 70 takes 5 hours 43 mins, but of course in practice the actual time saving will be far less.


I tend to agree - this is one of the reasons that I think the cost/benefit calculation has erroneous inputs. What would actually improve congestion would be more variable speed limits like the ones around the M42 round Birmingham - slow people down before they get to the congestion and everyone keeps moving, albeit at a slower speed than on a clear road, but still faster than if everyone bombs along at 70+ until they see the queue ahead, at which point the speed drops to dead slow - or the traffic stops moving entirely. The highways authority tries to do this by putting up advisory limits, but they're bloody useless because no-one takes any notice. This is because any individual driver loses out if he observes the advisory limit but no-one else does - when he reaches the queue, he's further back than he would have been if he'd ignored it with everyone else. They only work if enforced with cameras, so everyone observes them.

If the price of enforcement of the limit and of variable limits were an increase of the normal limit to 80mph, I think that overall the deal would improve road safety by picking off the cretins who just can't go below 85, and reduce congestion - double win. Doubt that's on offer though, because the primary reason for this announcement, along with the quarter million to empty the bins more often, is diversion and kow-towing to the Daily Mail readership.

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Re: 80 mph speed limit proposal

Postby iviehoff » 30 Sep 2011, 2:26pm

karlt wrote:Values are put on lives all the time in evaluating potential safety measures - I understand in rail it's around 1.6million. The above calculation appears to be 180 fatalities over 10 years, saving £1250.9 - that's 7 million per life. Compared with rail safety policies, that calculation argues for raising the limit.

The cost of accidents is not just the lives lost, it is also the clearing up after the accidents, delays to other travellers, and damage to property. In railway accidents I suspect such costs dwarf the values of life lost and injuries, but they are rarely explicitly taken into account in such calculations. Road accidents are generally cleared up much more quickly, so delays are generally much less, and road vehicles are worth a lot less than rail vehicles, so the costs to society of road accidents per unit of human damage I think should be less. Additionally, there is another reason for putting a higher value on accident costs for public transport as opposed to private transport - in the case of public transport you are paying to put yourself in the hands of a professional, who should therefore take more care to deliver you safely than you might achieve yourself; thus they should behave as if the value is higher.

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Re: 80 mph speed limit proposal

Postby Steady rider » 30 Sep 2011, 3:52pm

'New Direction in Speed Management' March 2000.
http://www.securite-routiere.org/docacr ... ne2001.pdf
page 46/49 refers to speed and injury severity

It says the probability of a fatal accident is related to the 4 power of the speed.

70 to 4 power, 24.01 million
80 to 4 power, 40.96 million
70% higher.

I think there are 4 cases of permanent disability for each fatality.
EU info
A. whereas in 2009 more than 35 000 people were killed and more than 1 500 000 injured in road accidents in the European Union,
B. whereas statistically for every fatal accident there are a further four accidents that lead to permanent disabilities, 10 that cause serious injuries and 40 that cause slight injuries,
C. whereas the social cost of road accidents is estimated at EUR 130 billion per year,

Mr Hammond will be contributing directly to killing people so that people can rush around to earn more income that may not need.

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Re: 80 mph speed limit proposal

Postby CJ » 30 Sep 2011, 5:08pm

The politicos have got to throw the motorist some kind of bone in order to distract him from the roll out of whole city 20mph zones. And 130kmph (81) is already the top limit in France, so let them have it say I, but only on real motorways.

In fact, let's have the whole French package. This includes an automatic reduction to 110kmph (68) - call that 70mph - whenever the road is wet (okay, some drivers are too thick to notice if the road is wet so it'll need to be marketed as "wipers on, slow down") and the French motorway limit comes down to 100 (62) or can be as low as 90 (56) on stretches of motorway that are very twisty or steep or have a lot of junctions. Most French urban motorways have those lower limits. The British motorist is now accustomed to lower limits applying to some stretches of motorway, so it will not be difficult to retain our 70mph limit where necessary or take it down to 60mph in some places.

I do not think it can seriously be suggested that the dual-carriageway limit be increased also. In France it is 110kmph, reducing to 100 when wet. Perhaps the most appropriate response of cyclists to this topic would be to demand a simultaneous reduction in the dual carriageway limit to 60mph, since we do sometimes have no option but to use those roads.

With all those extras, the headline 80mph could be a trojan horse for an overall reduction in vehicle speeds, with consequent fuel, CO2 and safety benefits. Let's hope the politicos are bright enough to have thought of that.
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Re: 80 mph speed limit proposal

Postby NUKe » 30 Sep 2011, 5:28pm

Well said CJ
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