How the DfT report enables Local Authorities to implement Wide Area 20mph Limits

Jesse Norman MP, the Minister for Transport has written to Councils saying the “WS Atkins report confirms public support for 20mph”.  Many Local Authorities are now reviewing 20mph policies and re-interpreting DfT guidance.

Jesse Norman’s letter[1] on the 20mph Limit Evaluation[2] of 22 November 2018 confirmed public support for 20mph and shows how Local Authorities can implement 20mph schemes successfully.

“Early engagement and buy-in from other stakeholders, including cross-party support from local councillors; clear articulation of the scheme’s rationale, objectives and outcomes; and tailoring of schemes to local circumstances were crucial to [delivering] a scheme to the anticipated quality, programme and cost”.

Mr Noman’s letter emphasises certain aspects of the DfT evaluation:

  1. 20mph is extremely popular: 70%+ support 20mph speed limits.
  2. Benefits of 20mph: quality of life and community benefits; encouraging healthier and sustainable transport modes such as walking and cycling.
  3. Confirms existing guidance (from 2013) on setting local speed limits.
  4. Around 1mph reduction in median speeds and a greater reduction from faster drivers.
  5. Insufficient evidence to draw conclusions about casualty reduction, except Brighton city centre, where casualties reduced significantly. 20’s Plenty for Us notes that casualties have reduced by 20%+ in many places[3] and the dataset used by the DfT could have been anticipated to be too small.
  6. Cycling and walking levels are significantly up in 20mph areas.


Mr Norman’s letter contained some errors and omissions:

  1. Where the letter states that the authors found insufficient evidence, the evaluation actually shows that the case studies areas chosen had insufficient casualties to be able to show whether or not the evidence was statistically significant.  See our critique at
  2. The letter omitted to say that speeds in the area surveyed were already low and the authors acknowledged that lower speeds were not expected.
  3. The letter did not say that the median speed from TomTom data is very suspect – biased by only capturing an estimated 3% of traffic with a disproportionate sample of men, non-local and business users in high end vehicles. Using the median dampens down the effect of slower moving vehicles.
  4. There was no reference to enforcement, when the report confirms non-enforcement as a large factor in low compliance.

The problem

DfT guidance encourages Local Authorities to implement 20mph in residential streets and town/village centres. Councils that interpret the 2013 guidance narrowly often insist on physical calming on faster roads, but then reject the scheme due to the expense.  This means missing the opportunity to agree popular schemes which would lower speeds and danger overall, despite the DfT report showing that speeds reduce most on the faster roads.  Many Local Authorities now include roads in excess of 24mph with limited physical calming for consistency of limit and to cut the number and severity of casualties. Note that Parish and District councils have no statutory responsibility or duty for setting speed limits. That rests with Traffic Authorities. Equally Traffic Authorities do not have the power to devolve that responsibility to lower level elected representatives.

We can choose to make streets better places

From a ‘can do’ mindset of wanting built up area streets to become increasingly vibrant and liveable, the report leads us to these conclusions:

  • A 20mph limit should be the default for urban and village streets with exceptions only where justified.
  • 20mph limits should be subject to robust and routine enforcement.
  • Intelligent Speed Adaptation (ISA) should be mandatory on all works vehicles, such as London Buses.

Possible solutions also include

  • Widening interpretation of DfT guidance to include roads with pre-speeds of 25mph+ with limited physical traffic calming and psychological calming to change mindsets, eg repainting to suggest narrowing and clear marketing of the benefits of 20mph speeds to drivers.
  • Embedding 20mph as the default for residential streets and town/village centres and new developments, in Council Active Travel Strategies and enable bids for sustainable transport funds for 20mph schemes.
  • Lobby for 20mph as a duty of care that all citizens should be able to enjoy; already in place for 25% of the UK population and now being discussed nationally, with cross party support, for Scotland (Safer Streets Bill) and Wales.

Wide-area 20mph schemes are popular AND cost effective - £3-5 per head invested in 20mph pays back in fewer casualties in about six months! It’s a great use of tax payer’s money for a policy with high levels of public support.


[1] Jesse Norman letter reference




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  • Jamie Wood
    commented 2019-10-03 10:12:50 +0100
    Do you need me to repeat my post? The Norman letter is based entirely on the Atkins report. The Atkins report says a a small, but statistically significant, increase (5%/2%) of people self-reported walking/cycling more. Your misquote of this info is being propagated.

    I am not against 20 per see, but you must use a proper evidence base, or you create problems for others.
  • Rod King
    commented 2019-10-03 09:35:34 +0100

    Both Atkins report and the Norman letter say that there was a “significant” increase in cycling and walking.

    The reference you gave is an abstract only. Being dated 2010 I doubt whether it has taken into account wide-area 20mph limits as implemented over the last decade.

    We are all in favour of comprehensive measures to increase active travel. So are you. But please don’t blame our success at gaining widespread adoption of 20mph limits as per recommendations by WHO, ETSC, OECD, iRAP, Global Network of Road Safety Legislators, ADPH, RCPCH, Sustrans, BRAKE, RoadPeace, Living Streets, UK Cycling, etc as a reason for your own failure to to persuade local authorities to adopt other measures as fast as you would like.

    Maybe if you were to concentrate on campaigning for what you want rather than campaigning against other fellow active travel activists then you would be more successful.
  • Jamie Wood
    commented 2019-10-03 08:59:30 +0100
    So what you are saying is that no, you cannot find evidence, or even defend yourself against my deduction, to support the emboldened 10 word bullet point in this article.

    You misunderstand my point about status quo — government is looking for easy ways to take action. We need to find measures to facilitate true modal shift. If organisations are pushing that 20mph zones create modal shift, when there is no evidence that they do, then that is a problem.
  • Rod King
    commented 2019-10-02 21:51:58 +0100

    There were 731 words in our briefing. In 10 of those words we commented on cycling and walking levels changing.

    I would be pleased to view the particular Pucher report from 2010. Perhaps you could give a reference.

    I will forgive your ire, but if you want to find an evidence base to challenge local authorities in improving cycling measures then please do so. Having campaigned for 20mph limits for some 15 years I can assure you that it is has never been “the status quo”. But we have been very successful in shifting authorities away from a “putting the car first mentality”. 20mph limits are not a “silver bullet for cycling” and we have never portrayed them as such. They bring benefits to a very wide range of people and transport modes. They have been successful in catalysing serious debates and interventions for active travel. Often this results in authorities being sensitised to those needs and implementing many complementary initiatives to encourage and grow cycling. These can include training, segregated facilities, cycle boxes and cycle hire.

    This is borne out by cycling representatives across the country and indeed world, calling for default 20mph or 30km/h limits in urban areas.

    I am not aware of local authorities implementing 20mph limits and then saying “job done” as far as cycling is concerned, any more than I hear of authorities implementing 20mph limits and deciding pedestrians no longer need crossings or pavements. That is not my experience of being involved in implementations around the country.

    May I wish you success in your campaigning for better cycle initiatives that can complement the developing public consensus that 20 is plenty where people are, whether they are on foot, on bicycle or simply standing at the side of the road.
  • Jamie Wood
    commented 2019-10-02 17:04:46 +0100
    I am familiar with the term, but you don’t answer my question about why the findings were misrepresented on this page, or why the important qualifications, “small”, “statistical”, “self-” were omitted. Most importantly this was self reporting, not measured increase. The maligned Atkins report is very clear on this, but that part you seem happy to lift and distort.

    The problem is that the Atkins report is not out of line with other reports, at least for cycling (that is the bit I object too). Pucher et al. (2010) gives a clear breakdown of measures for improving cycling and finds there is no statistically significant increase in cycling in 20mph zone.

    Forgive my ire, but I wish to find an evidence base to challenge local authorities in improve cycling measures. The misrepresentations on this page are proving a hindrance and a device for permitting the status quo (“business as usual”) by just banging up 20mph road signs that have little to no impact.
  • Rod King
    commented 2019-10-02 15:13:46 +0100

    The use of the word “significant” is used in a statistical context.

    Of course modal shift is also affected by complementary active travel measures. Unfortunately the case studies chosen in the Atkins report are very small and no attempts were made to understand the effect of other factors such as enforcement, engagement, cross-party support, public health involvement, active travel promotion, etc.

    We were also pretty unimpressed with the rigour of the Atkins report. Many questions are left unanswered. See
  • Jamie Wood
    commented 2019-10-02 09:25:40 +0100
    This is appalling misrepresentation:

    In Atkins: Self reporting does in indeed show a 2% increase, but there was no counts to verify this and the dominant response was “Nearly all residents said that they are walking (95%) and cycling (97%) ‘about the same’ amount as before the 20mph limit was introduced.”

    In Norman: The self was dropped, so we now have “Overall, there was a small but statistically significant improvement in reported levels of cycling and walking.”

    Here: “Cycling and walking levels are significantly up in 20mph areas.”

    Please explain.
  • Andrew Saffrey
    commented 2018-12-13 16:54:36 +0000
    Do you mean by “Using the median dampens down the effect of slower moving vehicles” that the mean speed should be used instead.
  • Rod King
    commented 2018-12-12 15:00:21 +0000
    Actually, compliance isn’t so low. The DfT report says that in 20mph limits most people (70% residential, 85% city) travel at speed less than the enforcement threshold of 25mph. And that using TomTom data which is very biased. But like any speed limit enforcement is a key factor in compliance. So why not make it better.

    And, of course, the whole idea of a speed limit decided by the community is that it sets a community led maximum speed rather than an individual deciding what are “the right places at the relevant times”. And the report shows that wherever 20mph limits are implemented then support increases.
  • Peter Cook
    commented 2018-12-12 12:55:30 +0000
    If “20mph is extremely popular: 70%+ support 20mph speed limits.” then why is compliance with 20mph speed limits so low?
    Originally we were told that 20mph limits would be self enforcing as everyone wanted them, yet now there are many articles on this very site talking about the need for enforcement of 20mph limits / calling for vehicles to be fitted with automatic speed limiting devices.

    Dont get me wrong – in the right places and at relevant times I totally support 20mph zones / limits, but in my opinion they have been vastly overdeployed with a corresponding loss of public support.
  • Rod King
    published this page in Press Releases 2018-12-11 19:23:07 +0000