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.htmI 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