20mph zones and the Radyr chain

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This topic contains 10 replies, has 9 voices, and was last updated by  onllwyn 2 months, 3 weeks ago.

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    I’m a little bit surprised to see the community council somewhat undermine the benefits of 20mph zones in this months Radyr chain. As far as I can see they have not taken a balanced approach in forming an opinion and references seem dated (do they even call themselves “the automobile association” anymore?).

    I would urge people to do their own research on this matter if interested. I don’t need to direct you because I have 100% confidence that any research path taken will lead to the same conclusion. Almost every local authority In the UK and thousands of others around the world have a policy to implement 20mph (or 30kph) zones in urban areas. They did not arrive at that conclusion by accident… particularly when you consider that air pollution legislation is currently evolving faster than almost any other area of legislation. There is a lot at stake.

    Of course Cardiff council already has a policy to implement 20 zones and is currently doing so… so it matters very little what the community council’s ‘opinion’ is. I’m just confused as to why they appear to be forming a stance. Do they not want residents to benefit from the same improvements to their road environment that Riverside, Canton, Tongwnlais etc already has?

    We all need to be together on this. Either you are on the side of the 650+ signatories of a recent petition who want to see traffic calmed and a safer village for residents and the hundreds of school children walking out pavements each day… or you are on the side of the developers who want to turn our village into little more than a high speed access to the a470/m4 for 7000 houses. Personally I would like to see my community council stick their flag in the ground firmly to display who’s side they are on!



    Heol Isaf is generous to admit to only being ‘a little bit surprised’ at the statement from the Community Council.

    Let me remind us of the actual wording in the Community Council’s article. ‘it is interesting to note that recent reports have indicated that these 20mph [sic] have been been associated with increases in the number of accidents due primarily to impatient drivers overtaking other cars’.

    Parents of young children at our two primary schools will be greatly reassured that the Community Council finds it ‘interesting’ that, apparently, their children are at greater risk now than before the 20mph zones around the schools were introduced earlier this year. And this from a Council that was happy to take the credit for having had the two zones introduced.

    I personally do not find the potential injury or even death of a child because of 20mph zones ‘interesting’.

    What is ‘interesting’ is mention of the ‘Automobile Association’ and its recommendations. The AA is, amongst other things, part of the MOTORING LOBBY! In the case of the proposed introduction of 20mph limited roads in DublIn, for example, the only objectors were the AA. I wonder why! For the sake of precision, it should be pointed out that the AA (AA.plc) is no longer called the Automobile Association. It’s wise to check one’s facts before publication!

    On that note, I would second heolisaf in urging all interested parties to do their own research on this issue. There is considerable academic research out there, evidence-based research, which is central to the issue. I am happy to forward copies of research papers to those that would like to read them. One starting point would be the paper by Public Health Wales ‘Background Paper – Public Health Wales believes that lowering the default speed limit to 20mph in Wales could have substantial public health benefits’. This position paper has been very usefully and appropriately posted on the Radyr and Morganstown Hub Facebook page (https://www.facebook.com/RadyrAndMorganstownHub) by councillor Kieran Webster.



    I agree entirely with the comment from Heol Isaf.

    The road through our village, past our schools, from our homes to the shops, surgery, care homes and tennis clubs should be safe for pedestrians to walk along-it should not be allowed to become a through road into Cardiff or out from the new developments to the A470/M4. I have looked through the research and see only robust evidence that SUPPORTS 20mph zones in residential areas both in terms of reduced accidents (BMJ) and in reduced emissions (PHW) I have found nothing robust that makes the same conclusions that are published in the chain and would be very interested to see links to those articles. I can’t see why a community council would want to do anything but increase road safety, reduce traffic speed and encourage walking/cycling.



    It is disappointing that 650 signatories have been ignored. Not to mention non evidenced arguments that contradict the World Health Organisation, NICE, Public Health Wales and that is just the tip of the iceberg. Our village is a residential area, people live here and our future generations will be left with one very unpleasant legacy if we do not do something to make our community safer and healthier for all.

    Imagine you are 8 and have to walk to school along any of our roads as they are at present?



    This 2017 Factsheet produced by the Royal Society for the Prevention of Accidents is a worthwhile read in the context of 20mph speed limits.


    I’m sure Forum readers would also welcome research findings supporting the views of those that oppose 25mph limits.



    The professor’s comments fail to take in to account a number of important factors:

    1. Majority of traffic on Heol Isaf is travelling well in excess of 30mph. The recent Traffic surveys indicate high 30s mph is average speed. Therefore better comparison would be 38mph compared to 20;

    2. The intention of various road calming measures is to reduce traffic volumes on Heol Isaf. Fewer vehicles will mean less emissions in total;

    3. Safety: Slower speeds reduce number of accidents and the impact of the accident.

    I would be very disappointed if the Professor’s comments were taken in some way to encourage drivers to go faster as it’s “healthier”.



    The professor’s specialism is only relevant to uptake of pollutants in the body. As an academic, it is somewhat unusual to boldly cite qualifications and then comment on an area outside your field (i.e. vehicle emissions under different road environment conditions), without ensuring your opinion is evidence based.

    If anyone wants to review the ‘tests’ the professor refers to then go to the table on page 6 of the following:


    As you will see, overall, emissions are clearly reduced for dropping to 20mph. Based on this, the professor is completely wrong to say “as a generalisation this pollution is increased at 20mph”. Also, note that these emissions tests are done on rollers and do not account for the much larger emissions spikes that occur under acceleration which are obviously more common/prominent in 30 zones. You can literally see this in diesel cars as they accelerate. I’m surprised this massive confounding factor went without mention in the professor’s letter. Steady flows with as little acceleration/braking as possible are the key to emissions reduction.

    Speaking of diesel’s, as you will note from the table…. they are where the biggest emissions savings are made in dropping from 30 to 20mph. I would think this a massively important factor for a village which sees hundreds of archaic diesel busses, vans and illegal HGVs on a daily basis. I’m afraid the final comment made about luxury 4x4s and porches highlights nothing but ignorance regarding the true villains of road emissions.


    In some ways, it has to be positive that Radyr and Morganstown have a community where democratic discussion and community conversation occurs.

    Then, again: no other community in Cardiff has had to demand, in public, the road improvements – traffic calming, speed limits, safer crossings and the like – that are a right and are needed for the safety of our vulnerable residents.

    The evidence from the University of West England is that over time, there is clear, consistent support, in every regional adult population in Great Britain for 20mph limits – Radyr and Morganstown will not be any different.

    When 20mph were implemented in Local Authorities in England, such as Bristol and Calderdale, they found that scepticism increased as the scheme began to be a reality. Here, focus groups were important to deal with local concerns and the myths perpetuated by our beloved Daily Mail.

    But, the reality is that the University of West England social research, with YouGov, over 5 years, shows that where a 20mph limit has been installed, support for it subsequently rises.

    My own, personal, response to John Harwood’s points on emissions are:

    it is important to be aware of how motor vehicles perform in factory testing conditions, as John Harwood states. It is not that it is not important to consider this factor and there is continual improvements to car emissions out of the factory.

    However, all of the research and meta research I have read on environmental health impacts measure pollution, affecting air quality, in the real world conditions of performance and output on the road: so, there is congestion-induced NOx emissions (which governed most studies until a few years ago) and that is different to 20mph speed limit NOx emissions, where the research is beginning to show improvements in air quality; there is the impact of breaking and accelerating, with 20mph producing smoother flows of traffic and more alternative non-NOx/PM emitting travel.

    Public Health Wales and researchers are clear that there is no conclusive evidence that every emission improves, although the rapid change of technology means researchers are always ‘catching up’ in their measurement strategies; but that, there is emerging evidence of improvements in some emissions, even in NOx emissions, in established 20mph areas; and, overall, there is a net improvement in air quality and this could have an overall positive economic and disease-outcome contribution to the overwhelming public health benefit of 20mph limits.

    John Harwood also raises some good points about the importance of ensuring compliance, improving consumer choice and delivering integrated and inexpensive public transport.

    My response to Ralph Vaughan, Chair of the Community Council, on accident rates is:

    The BMJ discourse shows that what is happening is that 20mph areas are increasing, so there are more raw accidents in 20mph areas. However, the data from Europe and Local Authorities in England is that where there are wide area 20mph limits the number of incidents reduces and the number of incidents of life-endangering impact.

    In addition, as most people already know, the rate of fatalities or life-impacting injuries is much reduced at 20mph, as compared to 30mph. This is due to the physics of impacts between pedestrians and vehicles and their weights, shapes, and predominantly their speed.

    As has been mentioned on this thread, there are a whole host of other public health benefits to reducing average speeds to the low twenties mph mentioned on this thread: from increased physical activity and active travel to increased local commercial activity and social interaction.

    The University of Bristol has found that for every 1% reduction in average speed there is a 6% reduction in fatalities.

    The international research, and Cardiff’s own figures through their 20mph schemes, show that 30kmh (20kmh) limits lead to an average reduction of speed at the 85th percentile and the 50th percentile.

    The only real counter-evidence has come form the Department of Transport, whose study seemed to show that speeds go up after 20mph limits are introduced. However, after a freedom of information request was able to scrutinise the study and its method, it was evident that all 8 of the roads, chosen by the DoT were completely free-flowing through roads, such as industrial estates.

    The University of West England research concludes that most people want 20mph and are looking for the Police to enforce it, so that it works. As John and Ralph state, compliance is an issue – I agree that there is no point doing something if it has no effect … however, the evidence shows that it does have an effect on average speeds, casualty numbers, air quality and healthy living.

    There has recently been a reaction in the Print Media (Daily Mail / Telegraph etc.) that supports the ‘need for speed’ lobby; picking up on the odd misinterpretation of statistic; but, the actual evidence is that the weight, globally, is with a 30kmh default speed limit where people live, work, learn and play.

    The reality is that, within the next 10 years, we will either persuade Cardiff County Council to invest in a proper road improvement scheme, with demand restriction, traffic calming and safer crossings – the evidence is that Morganstown and Radyr has 600 metres between crossings and incredibly high, illegal speeds – or it will happen through Welsh Assembly Legislation.

    My own view is that I prefer the sooner option.

    There may be those who argue that individuals should have the liberty to drive at the physical limits of the road or historic speed limits. These may be hot-hatch boy-racers or alpha men and women of the middle classes.

    However, I am happy to say that, after 30 years experience and considering the evidence, I am in favour of demand restriction, traffic calming, safer crossings and a 20mph limit, throughout Radyr and Morganstown, as soon as possible.



    Like others, I was more than a little surprised to see the articles in The Chain.

    Having been through all of the evidence in great detail, but also having studied basic physics, I find the perpetuation of the notion that crashes increase in 20mph zones flabberghasting. 20 reduces both the risk of crashing and the risk of serious injury should a crash occur.

    And yes, while the evidence around air quality is less clear cut, there is no evidence of substantial increases in air pollution. The as yet un-published results of a study currently underway in the UK also suggest improvements in air quality for all pollutants.

    But, what I find fascinating about the evidence in relation to 20 is the lack of evidence of harms. We are all aware of the “side effects” of medicines that we are prescribed. In public health terms, the benefits of 20 are huge and the side effects are non-existant.



    I have to say, I am not surprised one bit by the attitude displayed by the chair of the community council. There is a reason we do not have the correct safety measures in place in R&M and it is because of individuals and attitudes like this.

    In my opinion it is at best misinformation. Why on earth anyone would not want to make roads safer for our residents god only knows, and these people are suppose to represent us…well they certainly don’t represent me and given we have just put in the largest petition for road safety measures (I believe) Cardiff has ever seen, I would also suggest it does not represent our community.

    The article was a disgrace and should be retracted, and there should be a full blown apology for using his office to provide a personal unsubstantiated opinion.

    I am also disappointed by the Radyr chain for allowing such a one sided opinion.



    Here is a link to Radyr and Morganstown Community Council’s response to Cardiff Council’s draft scheme layout for highway improvements:


    In summary, the response states that Radyr and Morganstown Community Council:

    welcomes the proposed works
    wants to work with Cardiff Council to agree a comprehensive scheme that will make our community a better and safer place to live.
    wants to agree with Cardiff Council a timetable for delivery of the scheme within as short a time as possible.
    believes strongly that providing a limited number of improvements, making some parts of the road safe whilst leaving other parts in a dangerous condition, should not be thought of as ‘enough for now’.
    believes that the work should begin with new tabled zebra crossings at Morganstown, Min-y-Coed and Radyr Health Center – along with additional provision by Radyr Comprehensive School.
    agrees that existing zebra crossings should be tabled
    wants to work with Cardiff Council to ensure successful delivery of a 20mph zone, as an integral part of the scheme
    would like to see all crossings catering for cyclists, if possible.
    agrees that the crossing near Station Road should be upgraded to a tabled Puffin Crossing
    would support the introduction of a 20mph limit, based on best practice
    requests a tabled Pegasus Crossing near Radyr Farm Lane, to enable pedestrians, cyclists and horse-riders to cross safely
    requests that thought be given to providing safe passage for motorists living east and west of Heol Isaf and Ty Nant Road, as they seek to turn left and right onto those roads
    believes that a safe-cycling strategy should be developed for Radyr and Morganstown
    requests that the risks associated with the junction of De Clare Drive with King’s Road should be addressed,
    requests that a pavement should be installed along the short length of Windsor Road which does not have one at present
    requests that various options should be considered with regard to the future use of Golf Club lane
    asks that signs be erected to discourage fly tipping on Golf Club Lane.
    supports changing train ticket pricing to remove the incentive to catch trains fom Radyr rather than Taffs Well
    requests that the safety of pedestrians crossing the lower end of Drysgol Road should be considered
    requests that Cardiff Council considers measures to ensure that the propsed works do not result in drivers using other routes through Radyr and Morganstown, thus transferring risk to other sections of road.

    The response has been sent to Councillor Caro Wild (Cardiff Council’s Cabinet Member for Strategic Planning & Transport); Paul Carter (Head of Transport at Cardiff Council); Mark Drakeford AM; Kevin Brennan MP and the Welsh Government.

    Cllr Huw Onllwyn Jones

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