20 mph Zones

[rodk]

HI everybody

In my last post I think I said thank you for your interest and engagement. I have purposely refrained from responding to the more personal attacks from certain people.

Thank you Chrisl for your request. I think that I agree with your comment. Its about shifting not only the justification of the exceptions (ie to over 20 rather than under 30) but also endorsing a social norm which is already prevailing.

But I will try and clarify what is being suggested. First let me add some context. The 30mph limit was set in 1934 (and implemented in 1935) as being better than not having any limit. The figure was a compromise being higher than the 20mph limit applying up till 1930 and up to 1957 for heavy goods vehicles. Then there were 1.5m vehicles on the roads, now there are over 30m. They may have become smarter, faster, better braking and safer for the occupants, but we humans are just as fragile, as flawed and prone to make mistakes as we have ever been.

In the 1990's it was recognised that there was a benefit from setting a lower limit on some roads. These were duly done with heavy physical calming and termed zones. 20mph limits without physical were also used but only in isolation on short stretches of roads such as schools. Zones were deployed quite extensively in some London Boroughs and in some cities. Whilst they were very effective at forcing drivers to reduce speed because of the discomfort there were some problems :-

1) They were very expensive (about 50 times more than just signs)
2) They endorsed the idea that 30 was OK elsewhere and that only in these special places were lower speeds appropriate.
3) Neither drivers or residents liked them. The latter due to damage to houses and noise.

In 2006 the guidance was relaxed to suggest 20mph limits in areas where mean speeds were less than 24mph (previously it had been 85%ile speeds)

A number of authorities used this change to implement wide-area 20mph limits on most roads with arterials being left at 30mph. The first ones were Portsmouth, Oxford, Islington and Warrington. There began to be a recognition that a community-wide discussion about prevailing and allowed traffic speeds on primarily residential roads transferred the ownership from traffic engineer to community. An important consideration if the community was to change its behaviour. Speeds and casualties were found to reduce and across large areas which would not have been affordable with physical calming.

At the same time local and central government began to realise that the extent that vehicle usage and speeds were having a detrimental effect on quality of life, modal shift options, air quality and noise. Whilst casualty redution was a benefit there were actually far wider gains if traffic could be slowed and benefits gained. Plus a realisation that our roads were so congested that journey times from A to B were not dictated by your speed between them but the time stopped at congestion points, junctions and other constrictions.

Was there a way that we could take some of the "pace" out of our urban and village streets and make them better for all.

The 20's Plenty movement grew in parallel to this. It both made the case for lower speeds not as anti-driver but pro-community. Indeed, there are arguments that, just like on managed motorways, a slower and steadier speed can actually increase throughput and reduce journey times. In some cities there was a recognition that population and business growth could not be provided for by simply ramping up either car use or road space. Modal shift to walking, cycling and public transport was an economic as well as livability necessity.

It made this case successfully even though millions were being spent on car advertisements which praised the freedom and status of vehicle speed. And it was successful because it recognised what communities know whenever they are on the street. And it became successful because of the very wide benefits of bringing prevailing speeds down even by 1-6mph. And there is evidence that on streets with higher prevailing speed before a limit reduction then the reduction in average speed is greater. Of course you set many roads at 20 where speeds with a 30 limit were already low. You do this for consistency. But this dilutes the reduction on faster roads so overall you tend to get a 1-2mph reduction.

And now 15m people ( a quarter of the population) live in places where a 20mph limit is being set for most residential streets. In most of these arterial roads are left at 30mph. Arterial roads are usual exceptions but this will all depend on local factors such as casualty history, road usage, shops, schools, road characteristics, etc. In London TfL have developed a grid of "movement" v "place" to assist identifying whether the accent should be on vehicle throughput or liveable street streetscapes. A good rule of thumb in any high street is to look at any time for the number of pedestrians you see moving compared to moving vehicles. On most you will find whilst the presence of the vehicles are most noticeable the actual people moving in cars is less than those moving outside of cars. And of course no-one doubts that on such roads there will be a range of opinions.

This is all conditioned by central government which has progressively increased its support for lower speeds and limits based on many of the above considerations. In fact changes to guidance and signage regulations were made in 2006, 2009, 2011 and 2013. all of these increase flexibility and reduce costs in implementing 20mph limits.

So what we call for is the adoption of a 20mph default setting of limits for restricted roads. Exceptions have always been accepted as appropriate and necessary by ourselves. But these should be considered and reasoned rather than formulaic. That matches a developing consensus that throughout communities we should change that reference or norm to be 20mph and only go faster where conditions, including the limit, are special and appropriate for higher speeds.

One issue is that signage regulations insist on regular repeater signs and this is very much based on the 1990's model of 20mph limits being isolated and not the norm. But with increasing adoption then it becomes sensible to drop the requirement for such repeater signage and simply maintain the boundary signs. We have even suggested a change so that it is 30mph limited roads which should have the repeater signs.

I respect every one of you for your aspiration and achievement in becoming as good a driver as possible. This is not a criticism of those skills. But it is a recognition that this issue is about taking a bigger look at the bigger picture of our urban realm and how we can all best share those public spaces between building that we call streets. With so many demands for better health, liveable spaces, independent and active mobility, social mobility, lower social exclusion we must as a society "sweat" those assets that are our public spaces as well as we can. And that entails all of us contemplating the way we use our vehicles and not only our individual effect on our communities but also the cumulative effect of what we do. And in those places the maintenance of higher peak vehicle speeds simply does not add up as a societal benefit that compares to its dis-benefits.

20's Plenty is not and never has been suggested to be a panacea. Its not blanket and it should be applied with nuance, intelligence and consideration. And what is noticeable that the current implementation all include substantial engagement and education in why limits are being set at 20. It is also being deployed alongside many other complementary initiatives.

You can have a further look at our 50+ briefing sheets on so many aspects at http://www.20splentyforus.org.uk/briefings.htm

I trust that you don't mind me putting a tome of a post together. Somehow it seems more respectful than just a serious of one liners refuting some of the more negative posts. It allows me to explain rather than simply respond.

My best wishes

Rod

[WhoseGeneration]

Is a major reason that as a group we are strongly opposed to blanket 20's the fact that we generally show more respect for speed limits than the majority of drivers.?

Probably true, whilst often, internally, wondering why whatever limit.
I used to think such when, many years ago we regularly set off, on a bright August morning at about 6 to travel from Norfolk to Portsmouth for a ferry to France. Mainly dual As and Ms, little other traffic, me alert, car capable of cruising at 100 but no, think of the licence.

[RobC]

Hi Rod

Thanks for some of the most readable and informed posts I have seen on this forum. As a professional driver trainer I don't have a problem with 20mph limits, there will always be some inappropriate limits whatever the speed limit however if a single life is saved then the limits are worthwhile.
I have however been surprised at some of the negative responses from advanced drivers given the official stance from the advanced driving membership organisations.

My own driving style is basically Eco-safe where obviously safety comes before economy, however there does seem to be a divergence of opinion regarding emissions and economy. In 2000, the then Department of Environment, Transport and the Regions argued against reducing the 30 mph limit for fear of increasing emissions.

You say

20mph limits improve air quality
http://www.20splentyforus.org.uk/BriefingSheets/pollutionbriefing.pdf

The AA’s report, Fuel For Thought (Jan 2008) “accepts that targeted 20 mph speed limits in residential areas are popular and improve safety. Along shorter roads with junctions and roundabouts, limiting acceleration to up to 20 mph reduces fuel consumption"

This is what the AA published in Jan 2008

20mph limits can increase fuel consumption and emmisions
http://www.theaa.com/public_affairs/news/20mph-roads-emissions.html

Its not surprised that were confused!

Regards Rob

[rodk]

Hi Rob

Thanks for your comment.

Yes we are aware of the AA report which was written in 2008 and was commenting on 20mph zones which featured regular speed bumps.

In response to it in 2008 we issued our own press release :-

http://www.20splentyforus.org.uk/Press_Releases/AA%20spreads%20mis-information%20on%2020%20mph%20speed%20limits.pdf


It was the constant acceleration and braking that these induced which pushed up emissions. In fact if you look at the steady speed fuel comparison between 20 and 30 then the difference is just 10%. Later tests by Peter de Nayer on a range of cars found that there was a similar difference of up to 10% but this could be plus or minus depending on the gear ratios of the particular car. It found that a Ciroen C4 returned 99mpg at a steady 20mph.

Of course in practice the acceleration and braking plays a large part in fuel used and emissions. And with it requiring 2.25 times the energy to get to 30mph compared to 20mph then removing any 20-30 cycling (I mean acceleration and braking) has a beneficial effect on overall emissions.

Further and more recent tests have shown that lower limits show a generally positive result as far as emissions are concerned, especially for diesel particulates. See :-

https://www.cityoflondon.gov.uk/business/environmental-health/environmental-protection/air-quality/Documents/speed-restriction-air-quality-report-2013-for-web.pdf

Of course brake dust is also an issue and so reducing repetitive braking can be beneficial.

The note about the government advising that lower limits reduce emissions was taken from their 2013 guidance which states :-

83.Important benefits of 20 mph schemes include quality of life and community benefits, and encouragement of healthier and more sustainable transport modes such as walking and cycling (Kirkby, 2002). There may also be environmental benefits as, generally, driving more slowly at a steady pace will save fuel and reduce pollution, unless an unnecessarily low gear is used. Walking and cycling can make a very positive contribution to improving health and tackling obesity, improving accessibility and tackling congestion, and reducing carbon emissions and improving the local environment.

Once again, thank you all for taking the time and trouble to consider and debate this important issue.

Rod

[RobC]

Hi Rod

As far as emissions are concerned I run a diesel car and was given the government incentive of zero road fund licence based on emissions.
Now we are being told that pollution is so high in the capital, and emissions from diesel fumes so damaging that experts believe Boris Johnson will follow Paris' lead and ban the diesel cars from London's roads within the decade.

Whilst I don't have a problem with 20 mph limits especially from a road safety point of view, It seems to me that politicians can produce figures to support any argument!



Regards Rob

[chrisl]

Hi Rod,

Thank you very much for your informative response and the additional background detail.

Kind regards,

Chris

[trashbat]

As I suggested earlier, I can understand and appreciate the non-safety benefits of certain traffic restrictions. Traffic is disruptive and intrusive upon homes and residents, and the community deserves a stake in that, because the flow of traffic and freedom for road users doesn't automatically override that. Really I would like to see the decision and ownership devolved to those communities, but it is what it is. We could also get into the legitimacy of simply discouraging any vehicular traffic at all, which someone was taking umbrage at but personally suits me just fine. There are social benefits to this too, and it's not mutually exclusive to an interest in driving to say so.

The main issue I have with county-wide blanket limits (which, for clarity, does not mean every road, usually not arterial or rural ones) is that it's a blunt instrument.

Should this really be a 20? IMO the only justification could be to divert through traffic (it's a secondary route, neither arterial nor a rat run really) to another route. Because there is such a disparity between limit and reasonable speed, the zone has a poor degree of compliance with no enforcement, seriously harms the relationship between authority and driver, and leaves even the wilfully compliant driver as an outlier, potentially changing their behaviour for the worse. After enough of this, it's hard to have any respect for Lancashire's implementation of the scheme.

In the town centre there is no such complaint because this is very obviously a complex hazard environment appropriate for a 20mph limit, or indeed even less.

The secondary problem I have with stuff like 20's Plenty is actually its lack of ambition. Speed limits are not an intelligent mechanism - they are not just an authoritarian stick but a lazy one that doesn't dare to look outside the conservative constraints of how we already operate. There are much better things to be achieved in pursuit of the same objectives - Europe is scattered with such implementations. These are things like engineering road environments where the perceived appropriate speed is reduced without anyone telling you so, or where pedestrians are given much greater import, or where drivers are encouraged to make their own decisions through lack of signage, or where the general concessions to vehicular traffic are reduced. Putting a number on a stick and being satisfied with that falls a long way short of what could be done to make our communities more appealing.

[jont]

however if a single life is saved then the limits are worthwhile.

How will you ever know? And what about the lives lost? Time stolen from people travelling slower? Emergency services delayed? Child run over because if the car was going faster it would have been past before they stepped into the road.

It's phrases like this that really make me worried in this sort of discussion.

[RobC]

however if a single life is saved then the limits are worthwhile.

How will you ever know? And what about the lives lost? Time stolen from people travelling slower? Emergency services delayed? Child run over because if the car was going faster it would have been past before they stepped into the road.

It's phrases like this that really make me worried in this sort of discussion.

I'm also really worried in this sort of discussion in view of the figures I quoted earlier with significant reductions in KSI percentages.

A Transport for London review 16 of over one hundred 20 mph zones in London also found that they were very effective in reducing road injuries to children. In the zones, speeds were reduced by 9 mph and traffic flows by about 15%. Road casualties in the zones were reduced by 45% and fatal or seriously injured casualties by 57%. Again, significant protection was provided to the most vulnerable road users:
• Pedestrian casualties down by 40%, and pedestrians killed or seriously injured (KSI) down by 50%
• Child pedestrian casualties down by 48% and child pedestrians KSI down by 61%
• Cyclist casualties down by 33% and cyclist KSI down by 50%
• Child cyclist casualties down by 59% and child cyclists KSI down by 60%
• Car occupant casualties down by 57% car occupant KSI down by 77%
• Child car occupant casualties down by 51% child KSI down by 47%

Child run over because if the car was going faster it would have been past before they stepped into the road.

and

And what about the lives lost? Time stolen from people travelling slower?

You cannot be serious With comments like that the forum is fast loosing credibility

[jont]

I'm also really worried in this sort of discussion in view of the figures I quoted earlier with significant reductions in KSI percentages.

A Transport for London review 16 of over one hundred 20 mph zones in London also found that they were very effective in reducing road injuries to children. In the zones, speeds were reduced by 9 mph and traffic flows by about 15%.

16 of 100? What about the other 84 zones? And that suggests they're just moving traffic to other places

And of course stats over time don't take account of all the improvements in automotive technology that help too. Next thing is autonomous emergency braking.

Don't get me wrong - I'd like to see some traffic travelling slower in busy residential streets, but I don't think vast swathes of 20mph limits are a good thing.

[akirk]

I'm also really worried in this sort of discussion in view of the figures I quoted earlier with significant reductions in KSI percentages.

A Transport for London review 16 of over one hundred 20 mph zones in London also found that they were very effective in reducing road injuries to children. In the zones, speeds were reduced by 9 mph and traffic flows by about 15%.

16 of 100? What about the other 84 zones? And that suggests they're just moving traffic to other places

And of course stats over time don't take account of all the improvements in automotive technology that help too. Next thing is autonomous emergency braking.

Don't get me wrong - I'd like to see some traffic travelling slower in busy residential streets, but I don't think vast swathes of 20mph limits are a good thing.

It is easy for it to be misleading with stats...
was that:

- they only surveyed / studied 16 out of 100 zones and 100% had declined in casualties
- they surveyed 100 and in 16 the casualities had declined...

if the former, then it looks great... but unlikely to only survey 16 of 100 and find all result the same, and if that strong a link they would surely have checked the other 84 and published that it was 100% successful...

I suspect the latter in which case statistically it is a) a failure and b) probably other issues at play which had reduced the stats in those places, not the 20mph zone... it is very difficult to do proper testing as you can't control the other variables, but if moving to a 20mph zone was significant I would have expected better results...

Alasdair

[jcochrane]

Don't get me wrong - I'd like to see some traffic travelling slower in busy residential streets, but I don't think vast swathes of 20mph limits are a good thing.

This sums up how many of us feel. We have heard many times and read on this thread the arguments as to why a 20 limit is a good thing, where appropriate, on somes roads and who woul disagree?. But to then take that argument to justify a blanket 20 limit on all roads in a town, even where clearly not appropriate, is where many of us would disagree with campaigns we have heard from.

I agree with you Alasdair caution is required regarding these surveys and statistics there is usually more to them than meets the eye.You need to know, amongst other things, the basis on which the company undertaking the research was commissioned or what was the motivation if produced by a Government department.

[martine]

...As a professional driver trainer I don't have a problem with 20mph limits...

As a professional driver trainer, I do.

...if a single life is saved then the limits are worthwhile.

Really? So we'd best ban all vehicles then - that would probably save hundreds...sorry to be flippant but you get my point. Any road safety intervention is likely to be a balance and your statement above is too simplistic.

There is also the problem of distraction...at 20 there will be a bigger temptation for pedestrians to walk out without paying proper attention to their safety and ditto car drivers tempted to send that text whilst on the move. 2 wrongs don't make a right but I'm just trying to illustrate possible unintended consequences of imposing a low limit.

[RobC]

Hi Alasdair

As I said earlier politicians can produce figures which support any argument. No survey or vote is representative of 100% of the population you either accept Rospa's figures or you don't.

What is IAMs stance on 20mph limits? I understand that the IAM commissioned a survey, but only the views of 1001 people of our total population of 60 million were represented.

http://www.iam.org.uk/images/stories/policy-research/iam%2020mph%20survey.pdf

Rob

[martine]

What is IAMs stance on 20mph limits?

http://iam.org.uk/20mphlimits

...I understand that the IAM commissioned a survey, but only the views of 1001 people of our total population of 60 million were represented.

http://www.iam.org.uk/images/stories/policy-research/iam%2020mph%20survey.pdf

A sample of 1001 can be statistically significant (if done properly) - it's common to use such a size in government and commercial surveys.