Stop Press Rod King of ’20 is Plenty for Us’ popped in to join in the debate below. Scroll down to ‘Postscript’ to check it out. We reproduce all his comments verbatim along with our replies. (He obviously knows us well … he thought he was talking to a place called Adcocks Green … )
Birmingham City Council have just run a Consultation: ’20 MPH is Plenty’. (Results not yet in.) Do you want 20 MPH speed limit signs on most Brum roads?
Sounds cool? Have a good look at these pictures.
One well known, and slightly confused, Brummie social media pundit recently asked in surprise on Twitter ‘Don’t you support the 20 mile thing then?’ Do you know the difference between a 20 MPH speed limit and a 20 MPH zone?Does it really matter? It’s all an, um, ‘thing’ really? A ‘thing’ which is a ‘good thing’ (or a bad one depending on your point of view.)
An apple and an onion are both sort of spherical sort of food ‘things’ too. So only a real fusspot would bother about whether they were biting into a raw apple or a raw onion? Who cares? It’s all food? Of course that’s nonsense. Eating one of these raw will probably make you cry. It might turn out to be a bit the same with zones and limits as well.
What is the difference then between a zone and a limit?
The Royal Society for Prevention of Accidents site is very helpful here:
There are two distinct types of 20mph areas possible:
20mph zones, are designed to be “self-enforcing” due to traffic calming measures which are introduced along with the change in the speed limit. Speed humps, chicanes, road narrowing, planting and other measures are typically used to both physically and visually reinforce the shared nature of the road.
20mph limits, which consist of just a speed limit change but no physical measures to reduce vehicle speeds within the areas. Drivers are alerted to the speed limit with 20mph speed limit repeater signs.
Now have a look at this little look now at this set of stats.
What do you notice? That’s right – Traffic calming (zones) lowered speeds by an average of 9.3 mph and static signs by just 2.2 mph.
But that’s a long time ago, perhaps … ? Yes it is a long time ago. Let’s have a look at how things have been shaping up since. Have they changed? Both the National ‘Twenty is Plenty Campaign and Birmingham City Council is quite fond of quoting the findings of Portsmouth City Council, which installed across the board 20 MPH speed Limits in their city in 2007-8. This finally resulted in an overall lowered speed of just 1.3 MPH and according to one report (Atkins consultancy 2010) whilst casualty rates fell by 22% this did little more than reflect a national average fall in accidents at the time. The Department for Transport agree. In DFT Circular 2013: Setting Local Speed Limits they note:
Research into signed-only speed limits shows that they generally only lead to small reductions in traffic speeds […] 20 MPH speed limits without traffic calming reduce mean speeds by about 1 MPH on average. (p. 24, Paras 95-6.)
On the other hand, a forward-looking ‘zone‘ scheme in Hull set-up in 2003, concentrating on selected areas, shows a 56% decrease in accidents. (Birmingham City Council September 2013 Briefing Sheet)
Ah but zones are so expensive? You can get a far bigger area covered if you just put up signs?
Zones don’t have to cost a lot. Two of the most effective modern types of zone do not use humps or road narrowing at all, but still very effectively use physical and psychological measures to slow down traffic. In Broad Street in Birmingham wide centre strips called median strips help to slow traffic down by causing it to mainly stay in a confined area, although this can perfectly safely be crossed; simple but effective. Here is a median strip.
This one is especially for Rod King of ”Twenty is Plenty for Us’. Patriotic Rod was upset that our last picture was not British. So, here you are Rod – a median strip that is British to its very core – Walworth Road, London. It comes fromManual for Streets 2(2010) – p. 105. This a work we have been very impressed with. Author Phil Jones gave Phil Jones gave us a very interesting presentation on MfS2 in 2010
Take a look at this video of Park Lane, Poynton. This traffic calming piece of road saves by not using a controlled pedestrian crossing which costs around Â£100,000 to install. Nothing much happens for twelve minutes; that’s the point. Wait until the camera pulls back at the end to show you the road design.
Next point: do we really need limits everywhere? Is everywhere equally dangerous? Of course it is not. Just about everyone knows this is rubbish. So why not concentrate designed traffic calming where it is really needed, rather than take the money that was being used for this to scattergun the whole city with signs? Ask the people of Sampson Road, Sparkbrook what they think about this idea. Sampson Road has recently suffered two road fatalities. They already have a prominent ‘slow’ sign on the road which is obviously doing nothing. They have asked for a ‘zone’. They are told they can only have a sign, because that is now City-wide policy. How confident and happy would you feel about that, and feel about knowing that the money that could have gone to pay for your safe zone is paying for signs in 90% of Brum instead?
Now, what’s the most dangerous part of Acocks Green? Where do most accidents happen on the Warwick Road? Take a little looksie at this screenshot of an accident map for the years 2005-12 from www.crashmap.co.uk (Which is used by Birmingham City Council.) Notice the Warwick Road: the bit between roughly Dudley Park Road and Oxford Road. That’s our shopping area – where we were promised a Zone, before the promise was withdrawn. That’s our most accident prone area.
Acocks Green was told it was going to have a zone in Acocks Green village on the Warwick Road in July: safer, more attractive, more pedestrian friendly and good for increasing footfall and getting people to use local shops. We were going to be a model village for Birmingham – a showcase village. Then in November we found out that we were not going to get a zone after all – just a Limit, because the Council is not ‘doing’ Zones anymore. Just picture how excited we were when we found at that we were getting a Limit not a Zone. (Or maybe don’t try that at home … ) No parties to celebrate that the average drop in speed on the Warwick Road through Acocks Green village is likely to be around 2.2 mph (on the optimistic side – Portsmouth 1.3) as opposed to 9.3 mph?
But signs everywhere will reinforce the idea that there is a rule, and everyone will go more slowly, so it’s still a good idea? Oh yeah? Remember Portsmouth – that magic area which introduced across the board limits signs … and achieved an overall 1.3 MPH drop in speed. Why so low? Many people don’t decrease their speed when they don’t have to. Whether they do it by more old fashioned physical methods or more modern psychological methods zones have a very good record in reducing speeds where we need speeds to be reduced. Sure they cost more than signs. That’s why they are not put everywhere, but where they are needed. Don’t ask Portsmouth. Ask Hull. Ask Sparkbrook. Ask Acocks Green.
Why not tell the Council that you are not taking signs for wonders? Tell them ‘Please don’t zap the zone. The consultation is now closed, but you could always drop a line toPeter.A.Bethell@birmingham.gov.uk
How flattering – our little blog page has upset Mr Rod King of the ubiquitous and well-funded ‘Twenty is Plenty for Us’ national movement. Let’s see what he has to say. Our responses in red.
I would be pleased for 20’s Plenty for Us to engage with this group and discuss the relative benefits of zones and limits. However, it must be noted that many of the assertions and information given above are actually incorrect. The 20mph limit sign shown is a US sign and is not legal in the UK. Yes – we were aware of that. We needed a picture of a sign to make a visual point, and could find no British ones. However, we do realise that we need to get these things right because foreign pictures could drastically alter the entire content of the argument. It is possible that the apple is Canadian – perhaps Mr King could be good enough to check that for us as well? The 20mph limits in Portsmouth did record a 22% reduction in casualties against a 14% over the same period on all UK roads. That’s a 50% greater reduction in casualties. In addition it must be remembered that national average was across all types of roads and is hardly comparable with Portsmouth which is the most densely populated city in Europe.A whole 8% reduction – blimey – it is almost the same as the reduction achieved by zones in Hull (56%) … or perhaps not? In Warrington the 20mph pilots in residential areas resulted in a drop in casualties that was 27% higher than the rest of the town over the same period.The British Medical Journal (2009) made a study of zones in which they found that the average reduction of accidents in zone areas was 41%
Poynton is effective but the cost was Â£3.5m. Hardly replicable. What is more, just 200m away in residential roads motorists are encouraged to accelerate to 30mph. You are confusing the main Poynton scheme with Park Lane, which is a side road. Did you get around to watching the video? Did you really think that what has been done here could cost Â£3.5 million? We accept that physically calmed zones are more effective than limits, but when you take the 50x cost into account they are 7 times less cost effective in speed reduction. You have completely failed to grasp the cost arguments. Portsmouth appears to basing its somewhat dramatic comparisons upon humps. In Acocks Green (An area which initially – apology accepted – you turned into Adcocks Green demonstrating you are clearly unfamiliar with it ) the cost would be very considerably less because we would not require pedestrian controlled crossings (Â£100,000 per crossing) if we had the type of crossing shown in Park Lane Poynton. In fact isolated small 20mph physically calmed zones endorse travelling faster wherever there is not physical calming. Evidence? The comment about average speeds reducing by 1.5 mph does not take into account that the speed reduction is variable. In wide-area 20mph limits you always get the largest reduction on the faster roads. Many roads stay at the same speed because they are already low. But they reinforce the idea that 20 is plenty where people are. In Portsmouth the reduction on the faster 20mph roads was 6.7 mph. Still less than the reduction which can be achieved in a zone, but the real issue is clearly comparative numbers of accidents, We have had some nasty accidents and it is those we are concerned about. Whilst I can understand the concern that Adcocks Green may have lost its opportunity to get a highly effective small 20mph zone. But the realisation by Birmingham City Council that it wants an effective and economic methodfor speed reduction across the whole city should really be seen as an opportunity rather than a threat. Within its plans BCC has already accepted that there could be some physical calming at appropriate places. Hallo: Try telling that to Acocks Green or Sparkbrook – both have been told they cannot have a zone. Two recent fatalities in Sparkbrook apparently mean nothing. Have you tried the Birmingham September briefing on speed limits. It makes informative reading in this respect:
Based on experiences elsewhere, guidance and clear benefits it is recommended that on 90%+ of all adopted roads in Birmingham the default should be 20 mph introduced through a â€˜limitâ€™ rather than â€˜zonesâ€™. The following type of roads should be included as 20 mph limits: all residential roads those with a designated high street function â€“ defined as â€˜primary shopping frontagesâ€™; roads designated as â€˜secondary shopping frontagesâ€™; â€˜Bâ€™ and â€˜Aâ€™ roads with school entrances or schools;and roads with other local trip attracters such as parks/ leisure facilities, Health Centres and hospitals, and public transport hubs and interchanges;
(In other words pretty much everything.)
Hence Adcocks Green residents may do better by working with BCC for the wide-area adoption of 20mph limits rather than opposing plans. Wide-area 20mph limits are being adopted in most of our conurbations and this is an intervention that bodes well for the future liveability of the whole Birmingham community. In your opinion … some of us remain rather less than convinced and rather more worried. Rod King – 20’s Plenty for Us