20mph and its role in London's Vision Zero Plans

London is developing its Vision Zero Plan to reduce casualties on London roads. Here is our view on how 20mph limits fit into those plans.

20’s Plenty for Us Blog: 20mph and Its Role in Vision Zero (in London)

Jeremy Leach London Campaign Co-ordinator 20’s Plenty for Us

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Although the number of those killed and seriously injured on London’s roads has fallen significantly in the past decade, it remains the case that in 2015, there were more than 30,000 casualties (of any severity) and, of those, 136 people were killed and almost 2,000 were seriously injured in the capital.

The policies that Transport for London (TfL) has developed to address casualties have evolved markedly in recent years and their most recent strategy embodies a Safe Systems approach for London’s roads and a reduction in the danger that people face in their daily lives. A major problem in London, as in many urban areas, is that over time risk has increasingly shifted towards those who walk and cycle, those often termed “the vulnerable road users”. Improvements in road safety have disproportionately benefited those already protected inside motor vehicles rather than those who are outside. In 2005, for example, 27% of those killed or seriously injured on London’s roads were car occupants; by 2015, this figure had fallen to 15%. By contrast, pedestrians made up 33% of those killed or seriously injured in 2005 and 34% in 2015 while those travelling by bicycle rose from 10% of those killed or seriously injured in 2005 to 19% in 2015. Clearly the task of reducing risk and danger amongst those walking or cycling is more difficult than it is amongst those inside motor vehicles.

In December 2015 the debate about Vision Zero in London began to be move forward when Val Shawcross (then a GLA Assembly Member) proposed a motion in the Assembly to adopt a Vision Zero approach to road danger. This was agreed unanimously with the aim in the longer term that “death and injury on our roads can be avoided if a serious effort is made to tackle the causes of the problem”. With Val Shawcross now the Deputy Mayor for Transport in Sadiq Khan’s Mayoral administration, there is a widespread belief that the ambition for road safety in London will move towards a Vision Zero approach (which in the longer term aims for no serious and fatal casualties on the roads). There were particular mentions in the Vision Zero motion that the Assembly adopted of the need to increase protection for those who are walking and cycling owing to the inherent dangers they face.

Many places across the world now claim to be adopting a Vision Zero approach to road casualties. Vision Zero originated in Sweden and in October 1997 legislation was approved in the Swedish Parliament that mandated the government “to manage and design the nation’s streets and roads with the ultimate goal of preventing fatalities and serious injuries”. Since that time it is more often urban areas that have taken the lead in embracing Vision Zero policies with cities in the United States such as Chicago, San Francisco, Boston and New York in the vanguard.

Both cities and countries have been swift to develop glamorous brochures of their goals of reducing casualty levels through Vision Zero policies but few have been clear about the policies that they will actually implement to achieve this.

Encouraged by the likely adoption of a Vision Zero approach in London, 20’s Plenty for Us and Living Streets have worked together to find the evidence for what really works in reducing casualty levels in built up areas. We have created a detailed report on the interventions that research has shown can be a springboard to rapid declines in casualty numbers. This can be downloaded here.

From this research it is clear that vehicle speeds are a significant contributor to road danger. For Vision Zero to be effective and to set casualties on a trajectory towards zero in the longer term, policies need to focus in no small part on speed and include:

  • Lower Speed Limits and 20mph. Research has shown that where speeds are reduced to a maximum of 20mph, casualties fall by more than two-fifths[1]. 20mph speed limits are becoming the norm across London and the task we face is to increase levels of compliance by drivers so that the full casualty benefits of lower vehicle speeds can be realised as well as creating an environment where more people feel safe enough to walk, cycle and take public transport. Overall it is now estimated that in Inner London (13 out of the 33 boroughs) two-thirds (64%) of the population lives on 20mph streets and roads and across the whole of London almost two-fifths (39%) of all Londoners now live on roads and streets with a 20mph speed limit. Many of the policies proposed to support Vision Zero are specifically aimed at increasing compliance with speed limits and 20mph limits in particular.


20mph speed limits at the IMAX roundabout in Waterloo

  • The Design of our Streets and Roads to embed lower speeds in road design and to have an especially focus on crossings and junctions where many casualties occur. For far too long in the UK the focus has been on moving (private) vehicles as swiftly and efficiently as possible. Little consideration has been given to the importance to the life of our streets of those on foot, those who cycle and people generally. Designing for people and for lower speeds makes a difference to casualty levels. In New York on Ninth Avenue in Manhattan, the introduction of a protected bike lane, pedestrian islands, and split-phase signals installed saw injuries to all street users fall by 58%. There are signs that priorities maybe starting to change in the UK. The launch of Healthy Streets in London[2] puts active travel at the heart of transport policy whilst at the same time as embracing Vision Zero. It is important that designing out danger is coupled with policies that promote active travel.



Blackfriars Road: Segregated cycle lanes reducing road capacity and lowering vehicle speeds.  

  • Speed Limit Compliance. There are encouraging signs that new vehicle technology can help drivers comply with the speed limit. TfL conducted a trial in 2015 where mandatory speed limiters or Intelligent Speed Assistance (ISA) was fitted to buses on two London routes. The trial found that “all buses fitted with ISA remained within the speed limit 97-99% of the time” and that “the trials were particularly effective when travelling through 20mph zones”. As a result of the success of this trial, TfL is providing funding for the roll-out of ISA on all buses from 2017 onwards. This has enormous potential for compliance in London where so many streets are now subject to 20mph limits and drivers often find themselves following buses. As the digital speed map of London shows, the majority of streets and roads in Inner London are now subject to 20mph speed limits and many parts of Outer London are also adopting 20mph limits. Over time, as ISA is rolled out across the bus fleet (which is renewed roughly every seven years), this policy will have a real impact on compliance with 20mph limits across the capital.



London Digital Speed Map from Transport for London – June 2016. 20mph streets and roads in green; 30mph in blue.



  • Enforcement. The 20’s Plenty for Us campaign has always been about everyone in society enjoying the benefits of lower vehicle speeds. Those on foot or those who are cycling feel the benefits of reduced intimidation and danger from vehicles while drivers themselves contribute to life in their communities by driving more slowly. But as 20’s Plenty for Us colleague Anna Semlyen recently argued in a blog post, supporting 20mph limits with camera enforcement can help deliver high levels of compliance with speed limits. There is strong evidence of the impact of both safety cameras and average speed cameras at encouraging compliance with speed limits and driving down casualties. In New York City at locations where they have been installed, Red Light Cameras (equivalent to our Gatso cameras) have seen a 20% decline in all injuries, a 31% decrease in pedestrian injuries, and a 25% decrease in serious injuries in the three years after installation. As for average speed cameras, the latest results for the A9 in Scotland between Dunblane and Inverness found that the installation of average speed cameras has led to the total number of casualties falling by 45% (with the number of fatalities down 43% and serious injuries by almost 63%). To date in London, TfL has only trialed average speed cameras on multi-lane arterial roads such as the A40, A406, A316 and the A20. It is surely time to understand how effective they can be in locations with 30mph and 20mph speed limits.


  • Other forms of enforcement such as the recently introduced Community Roadwatch[3] (CRW) collaboration between the Metropolitan Police and TfL also work to increase compliance and empower communities to play a part in reducing road danger. CRW is being rolled out across all London boroughs with local people encouraged to identify problem locations for speeding and then conduct sessions in collaboration with PCSOs.



Community Roadwatch with Simon Taylor – Herne Hill, Southwark

Overall then there does appear to be a shift towards a more people focused approach to transport in our cities and London appears to be in the vanguard of this in the UK. Vehicle speed plays such an important role as a source of road danger that Vision Zero policies must embrace an environment where 20mph rather than 30mph is the default limit and where all measures possible are taken to ensure that vehicles comply with those limits. This means that a whole range of policies need to be viewed together to deliver lower speeds and these will encompass designing roads and streets for a maximum speed of 20mph, the use of technology that helps drivers stick to those limits, enforcement of the limits and of course behavioural campaigns that back these actions up and emphasise the benefits of a transport system where the need for movement of vehicles is balanced with encouragement for people to walk and cycle and lead active and happy lives.

If you would like to read more about how we think that Vision Zero can be made effective, please see our report Delivering Vision Zero in London which has been produced in collaboration with Living Streets. Download here.

[1] http://www.bmj.com/content/339/bmj.b4469

[2] http://content.tfl.gov.uk/healthy-streets-for-london.pdf

[3] https://tfl.gov.uk/corporate/safety-and-security/road-safety/community-roadwatch

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  • Datere
    commented 2017-06-16 03:49:35 +0100
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  • Chris Paul
    commented 2017-03-01 21:52:24 +0000
    Well done. Let’s hope Manchester and Greater Manchester get started on this in the very near future. We – many and varied walking and cycling ‘healthy streets’ stakeholders – have been discussing this with the Labour mayoral candidate for GM, Andy Burnham. and his team. There has been a good reception and promise of commitments.