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20mph improves public health: Durham University

Wednesday 15th October 2014

20mph zones and limits are “effective means of improving public health via reduced accidents and injuries”, according to a new study by researchers from Durham University.

The findings are contained in a research review, ‘Go slow: an umbrella review of the effects of 20 mph zones and limits on health and health inequalities’, authored by five academics from the department of geography and public health team at Durham University. A summary of the findings has been published in the Journal of Public Health.

The report says that transport is an important determinant of health, and that there is a “well-established association between socio-economic status (SES) and risk of road accidents”.

The team used systematic review methodology to identify the effects of 20 mph zones (including speed limits and road humps) and 20 mph limits on health and SES inequalities in health among adults and children. They identified evidence from five international systematic reviews on 20mph zones and limits.

They concluded that overall, the results provide “convincing evidence that these measures are effective in reducing accidents and injuries, traffic speed and volume”, and “evidence that such interventions are potentially cost-effective”. The report also says that in two of the studies there were improved “perceptions of safety”.

 It suggests that “whilst there was no direct evidence on the effects of (20mph) interventions on health inequalities, targeting such interventions in deprived areas may be beneficial”. The researchers recommend “further controlled evaluations that specifically examine SES effects”.

Commenting on the report, Rod King MBE, founder of 20’s Plenty for Us, said: “The evidence in road safety, public health, active travel, noise reduction, emissions and simple livability all point towards default 20mph limits becoming the norm for UK communities.

“This research adds even more weight to the view that current blanket 30mph limits compromise public health in our urban realm.”

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If the indirect effects of lower speeds on health are to be considered, I would hope that noise-induced stress is taken into account - one of the bug-bears of modern living.
Hugh Jones, Cheshire

Agree (3) | Disagree (5)
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Idris
It is clear to the traffic authorities that have implemented 20mph pilots and looked at the results in detail that they have been pleased with the results and their contribution to road safety. These have always been followed by wide-area roll-out.

One issue for government is that each traffic authority has looked at this in an individual way and with different measurement methods. Hence it is entirely correct that DfT should be calling for an in-depth study in view of its past reluctance to even track mileage of 20mph or 30mph roads. In addition its review will be considering the benefits of 20mph speed limits for public health and wider community gains. It will also be looking at what levers can effect compliance such as enforcement and engagement. All of these will provide a very good basis for considerations of 20mph being adopted nationally as has or is happening in many other countries. Meanwhile its guidance is asking traffic authorities to give priority to "considering the introduction of more 20mph limits and zones, over time, in urban areas and built-up village streets".
Rod King, 20's Plenty for Us

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Whether 20mph areas lead to more or fewer serious injuries is not yet clear, though I have certainly seen some evidence that more. There must be ample evidence out there by now so why is the DfT so slow off the mark? I would have thought a competent researcher could determine the effect within a month or so.

Thanks for the reply, at last, about your signs. Because I put up election posters a few years ago I checked the rules. When it comes to public property, especially "street furniture" such as lamp posts and telegraph poles, the rules are quite strict (and rightly so in terms of possible distraction). Authority is needed and I seem to recall that there are criminal penalties for what is loosely described as "flyposting". Your reply implies that you have no such permission for the signs I see here and there in this area, on street furniture.
Idris Francis Fight Back With Facts Petersfield

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Idris
I can happily debunk every one of Brian Macdowall's 800 words but to do so may take more than 150. Those with an interest in road safety may well want to consider one of his sections within the article:

"The leader of Herts’ Lib Dems, Stephen Giles-Medhurst, has claimed that travelling at 30mph doesn’t allow for a child darting out into the road or a pedestrian having a momentary lapse and stepping out into oncoming traffic.

The implication that the law must be changed to make life easier those that disregard the law and the Highway Code is about as logical as forcing inter-city trains to crawl at a snail’s pace in case someone chooses to trespass on the track.

I sometimes hear that someone hit by a vehicle at 20mph might come off less badly than if hit at 30mph, but this is missing the point."

So there we have it "momentary lapses, kids being impulsive". Why on earth would anyone want to change a law to avoid killing or harming such people. And that idea of pedestrians coming off less badly if hit by a car at 20 instead of 30! What a preposterous idea!

And let's remember that most people live within 300m of a road that's probably left at 30mph. This means the maximum increase in journey time is just 20 seconds!

I presume in your reference to "our signs" you mean the Wheelie Bin Stickers that we sell to individuals or even the pdf files which some people may have downloaded and printed. Whether there is any authority to attach them to anything would depend on by whom, where and to what they were actually attached. Maybe next time you see one in a village you should do some door stepping yourself and explain to people how important it is for you to be able to drive at 30mph through their village.
Rod King, 20's Plenty for Us

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+5

Rod:
To dismiss the assessment by Brian McDowell without dealing with the points he makes, merely because he represents ABD, is yet another example of how 20's Plenty prefers to play the man instead of the ball. As indeed is your preference to dimiss the data and facts I repeatedly provide here as if they are merely my "perspective". For my part, I base my challenges to your claims on the evidence, not on the fact that you certainly have your own perspective, which in my view is based more on fantasy and wishful thinking that evidence.

I invite others here to read the Portsmouth data and report whether they think that the substantial increases in deaths and serious injuries on those roads are outweighed by Rod's usually nebulous and often selective claims of benefits.

One more point Rod, and for the third time of asking, does 20's Plenty have legal authority to attach its signs to what the authorities call "street furniture"? If not, then doing so is of course an offence.
Idris Francis Fight Back With Facts Petersfield

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Seems as though this 'study' is actually a 'review' of other selected studies - not much to go from the abstract, but I don't intend to pay $38 to access the full paper for one day - even then I doubt there would be much if any raw data. If I hadn't retired, I would have been able to access the paper via my University. There are no practical logical reasons why 20mph limits would have any of the benefits claimed - emissions wouldn't go down, speeds don't tend to alter noticeably, accidents would be rare anyway, claims for increases in walking and cycling use percentages to hide insignificant small actual numbers, effects on 'health inequalities' must be some sort of new politically correct fantasy that happens as soon as a 20 sign is erected.

20mph limits where I live are mostly temporary - limited to school arrival/departure times - but even they are pointless as the traffic is below 20mph to stationary anyway.

As for the question of who funded it - the taxpayer, as per usual, I guess.
Paul Biggs

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+3

Research was funded by Durham Council.
Anna Semlyen

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+4

Well Idris
We all know your perspective on speed limits. 20's Pointless is keen on 13 ton buses doing above 20mph on the residential streets of Worthing and of course the Conservative Home article was by Brian MacDowall from the Alliance of British Drivers. I don't think I need to say any more.
Rod King, 20's Plenty for Us

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+7

If as the report says that there is a “well-established association between socio-economic status (SES) and risk of road accidents” (more poor people get tagged than rich people). If the interventions are having an effect then that association means that they must be benefitting greater numbers of poor people than rich people. Yet the report further finds that there was no direct evidence on the effects on that association. That means that either the association is not proven or the effect is not proven which leads me back to my original question.
Duncan MacKillop, Stratford on Avon

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+6

Several years ago my own analysis of Portsmouth's 20mph data showed serious injuries 50% higher than had they followed national urban trends. I can now refer doubters to more up-to-date numbers at http://20spointless.org.uk/the-truth-about-portsmouth/ showing not only serious injuries substantially higher.

See also http://www.conservativehome.com/localgovernment/2014/10/brian-macdowall-why-20mph-zones-are-wide-of-the-mark.html which includes the point that 20mph causes more pollution not less.
Idris Francis Fight Back With Facts Petersfield

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Rod,
No slurs Rod, just robust challenges. Another "renowned academic institution" re-categorised their involvement in 20mph projects from "Improving Road Safety" to "Behaviour in Travel and Transport" when I drew their attention to the negative effect on casualties in 20mph limits. 20mph is clearly bad for road safety and no amount of rehashing of selected reports can change that.
Eric Bridgstock, Independent Road Safety Research, St Albans

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Eric (first post in this thread)
If you know who funded this report, and why, perhaps you'd like to share that information with us?
Nick Rawlings, editor, Road Safety News

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+18

Eric
I think that you have just demonstrated the difference between the approach of 20's Plenty for Us and Independent Road Safety Research. We issue a press release on the peer reviewed report of a renowned academic institution that has been published in a recognised and established journal.

On the other hand you retort with slurs on who funded it, your own presumptions of the studies and an article from the Romsey Advertiser. Need I say more!
Rod King, 20's Plenty for Us

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+13

Duncan
I think the clue is in the paragraphs in the article which say :-
They concluded that overall, the results provide “convincing evidence that these measures are effective in reducing accidents and injuries, traffic speed and volume”, and “evidence that such interventions are potentially cost-effective”.
and
It suggests that “whilst there was no direct evidence on the effects of (20mph) interventions on health inequalities, targeting such interventions in deprived areas may be beneficial”.

So clearly "convincing evidence on benefiting public health" but "no direct evidence of reducing health inequalities".

I presume that you do appreciate the difference between public health and public health inequalities or does it need further explanation?
Rod King, 20's Plenty for Us

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+5

Well, which is it? 'Convincing evidence' or 'no direct evidence'? Can't be both can it?
Duncan MacKillop, Stratford on Avon

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+2

There is nothing new here - it's a review of existing reviews.

Who funded it, I wonder? and why?

The review found "says that in two of the studies there were improved 'perceptions of safety'", by which they presumably mean pedestrians and cyclists said they felt safer. No reason to suppose public health academics would realise that feeling safer leads to lowered guard and actually BEING less safe (especially when traffic speeds barely change when 20mph is introduced and some increase!

It's hardly surprising that the wheels are starting to come off the unaffordable 20's plenty bandwagon

http://www.romseyadvertiser.co.uk/news/winchester/11509057.Winchester_s_transport_chief_labels_new_20mph_speed_limit__not_legally_enforceable_/
Eric Bridgstock, Independent Road Safety Research, St Albans

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