The potential for more 20mph limits in London in order to reduce road casualties should be fully explored through a borough-led pilot programme, according to a new report published the same week as the Government announced proposals to reduce speed limits on residential roads.
The report by the London Assembly Transport Committee – ‘Braking point: 20mph speed limits in London’1 – found that in areas of London where 20mph zones have been introduced by boroughs and Transport for London (TfL), there has been a 42 per cent reduction in casualties.
Some evidence suggests that the 400 existing 20mph zones (2) which cover 11 per cent of London’s road network – have also contributed to benefits beyond road safety, including improving traffic flow, reducing emissions and encouraging walking and cycling, although further research is needed.
The report concludes that implementing a borough-wide default 20mph limit all at once may prevent more casualties and prove more cost-effective than the current piecemeal approach of introducing individual zones.
In order to thoroughly test the case for borough-wide limits, the report calls on the Mayor to examine diverting some Transport for London’s £63 million road safety budget to support a borough-led pilot programme from 2010/11.
The pilot would involve two boroughs implementing default 20mph limits on residential roads but deploying different enforcement methods to assess which is most successful at reducing casualties as well as the most cost-effective.
Jenny Jones AM, who led the investigation on behalf of the Transport Committee, said that the report’s findings make a strong case for further work on the introduction of 20mph limits.
"We are talking about saving lives and improving Londoners’ living environment; surely this is justification enough for investing in a comparative pilot to test the best approach.
"Some boroughs are keen to expand on the successful zones they already have in place and I hope the Mayor and Transport for London will put in the necessary funding and effort to support this.
"The benefits of 20mph limits have not gone unnoticed by London’s boroughs. Eight (3), including Hackney and Southwark, intend to go beyond the use of zones and implement borough-wide default 20mph limits.
"The London Borough of Islington will have a borough-wide 20mph limit on all its residential roads by March 2010; the other six are developing the plans on a piecemeal basis by extending zones over a number of years.
"The comparative study of different enforcement methods recommended in the report should also monitor the impact of Islington’s borough-wide limit, which will feature a minimal enforcement approach using signage alone in many parts of the borough. A variety of enforcement methods can be used in 20mph zones, with average speed cameras a promising new option that should be explored."The report calls on the Mayor to investigate funding and pilot proposals with TfL and report back to the Committee by October 2009.
The relationship between traffic speed and a pedestrian’s chances of survival is clear:
* Hit at 40mph, 90 per cent of pedestrians will be killed;
* hit at 30mph, 20 per cent of pedestrians will be killed;
* hit at 20mph, 3 per cent of pedestrians will be killed.
Notes for editors:
1. Braking point: ’20mph speed limits in London’ is available at: http://www.london.gov.uk/assembly/reports/transport.jsp#braking-point
2. See map showing 20mph zones in London on page 14 of the report.
3. Islington, Hackney, Southwark, Brent, Kingston upon Thames, Lambeth, Tower Hamlets, Merton.
4. The report received cross-party support from Transport Committee Members <http://www.london.gov.uk/assembly/transport/memberstermsreference.jsp> at a meeting on 22 April 2009.
5. Jenny Jones AM, who led the investigation on behalf of the Transport Committee, is available for interview. See contact details below.
6. As well as investigating issues that matter to Londoners, the London Assembly acts as a check and a balance on the Mayor.