Suspending M4 bus lane breached air pollution law

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The Rt. Hon. Justine Greening MP
Secretary of State for Transport
c/o Network Delivery & Development
Highways Agency
Floor 4C
Federated House
London Road
Surrey RH4 1SZ

By post and email: Mr C Cooper, Floor 4B [email protected]

15 May 2012

Objection to the suspension of the M4 Bus Lane.  Your reference HA/M4/41/10/15

Dear Secretary of State

Clean Air in London (CAL) welcomes the opportunity to respond to the consultation on the Department for Transport’s M4 motorway (London Borough of Hounslow) (Bus lane) Order 1998 Revocation Order 201.  Details can be seen at:

CAL is a company limited by guarantee which campaigns to achieve urgently and sustainably compliance with World Health Organisation guidelines for air quality throughout London.

CAL is independent of any government funding, has cross-party support and a large number of supporters, both individuals in London and organisations.  CAL provides a channel for both public concern and expert opinion on air pollution in London.  This document provides both general and expert comments in response to the consultation.

Traffic is a major cause of air pollution in London which in turn causes thousands of premature deaths per year, and many thousands more instances of illness, chronic illness and disability.  For this reason, traffic measures are also measures to deal with air quality.


The Bus Lane operated between junctions 3 and 2 of the eastbound M4. It was suspended on 26 November 2010 under an Experimental Order under the Road Traffic Regulation Act 1984.

The Secretary of State for Transport has given notice that she proposes to make a permanent Order under section 6(1) and (3) of, and Part IV of Schedule 9 to, the Road Traffic Regulation Act 1984 on the M4 Motorway in the London Borough of Hounslow.

The effect of the Order would be to revoke the Order authorising the operation of the Bus Lane on the eastbound carriageway of the M4 between Junctions 3 and 2, between a point 19 metres east of marker post 21.8 and a point 12 metres west of marker post 16.0, a total distance of approximately 5.78 kilometres.  This would supersede the Experimental Order that is currently in force.

The suspension will remain in place until June 2012 when it is intended the lane becomes part of the Olympic Route Network for the London 2012 Olympic and Paralympic Games.

Report: M4 Bus lane

The report titled ‘The Analysis of the Impact of the Suspension of the M4 Bus Lane’ dated 5 April 2012 (the ‘Report’) and published on 11 April 2012 states on page viii:

Air Quality Impact

Nitrogen dioxide (NO2) concentrations at receptors in close proximity to the M4 are modelled to be higher with the suspension of the M4 Bus Lane. It is considered that this is as a result of several factors.

a)      The M4 Bus Lane displaced a proportion of the HDVs (i.e. buses and coaches) away from the inside lane, to the outside lane (i.e. the M4 Bus Lane). Without the M4 Bus Lane, HDVs are restricted to the two innermost lanes, closer to sensitive receptors adjacent to the M4.

b)      The average speeds on the section of the M4 adjacent to the receptors are higher in 2011 after suspension of the M4 Bus Lane.

c)      Traffic levels in 2011 are higher than in 2010, which contributes to increased NO2 concentrations.

Further detail is provided in section 9.1 on pages 40 and 41 of the Report.  From this it can be seen that increases in NO2 concentrations are predicted at all six locations considered all of which are in residential areas.  In five out of six cases, levels that already exceed legally binding limit values would be made worse.

Please will you provide us with a copy of the Air Quality Study, (Report Number. 0001UA003263NHR04M4) by Hyder Halcrow referred to on page 40 and in the Bibliography on page 81.


You will be aware that limit values must not be exceeded having been attained or air pollution worsened where they are exceeded.

The consultation does not provide adequate information in relation to the air pollution impacts not least by failing to publish the Air Quality Study referred to above.  Further, the Report provides no assessment as to whether the proposal is likely to have an adverse impact on the promotion of equality of opportunity under the Equalities Act 2010.

The Highways Agency’s own modelling suggests that removal of the M4 Bus Lane would lead to an unlawful increase in air pollution inconsistent with EU law.

There has been no, or no adequate, consideration of the impact of the proposals on particularly vulnerable groups or minority ethnic groups.

On the basis of the information provided, removing the M4 Bus Lane would lead to:

  • Aggravated breaches of the nitrogen dioxide (NO2) annual mean limit value (i.e. exceedance of the limit value which had been attained in 2010 and/or 2011 and/or thereafter); and
  • An increase in harmful concentrations generally.

For the reasons outlined above, this would be unlawful and CAL objects to the proposal.

CAL therefore concludes that the Secretary of State should reject the proposal to remove the M4 Bus Lane and reinstate it in June 2012 on the expiry of the Experimental Order under the Road Traffic Regulation Act 1984.

There should be no other outcome without further information and modelling all of which should be subject to further consultation.  CAL encourages the Secretary of State to propose full mitigation measures if the Bus Lane is considered again for removal e.g. reserving the use of the Bus Lane for car sharing and/or very low emission vehicles.

Please contact me if you have any questions or would like more information on any of the points raised in this letter.

Yours sincerely



Simon Birkett
Founder and Director
Clean Air in London


Isabel Dedring, Deputy Mayor for Transport and Deputy Chair, Transport for London
Hugh Sumner, Olympic Delivery Authority
Michèle Dix, Transport for London
Caroline Pidgeon AM, Chair, London Assembly Transport Committee
Val Shawcross AM, Deputy Chair, London Assembly Transport Committee
Darren Johnson AM, Deputy Chair, London Assembly
Stephen Joseph, Campaign for Better Transport
Jenny Bates, Friends of the Earth

CAL 182 0001-UA003263-NHR-07-M4-Air-Quality-Study-Fv2_3 February 2012 version

CAL 181 M4 bus lane M25DBFO_RO1656HADO_-_The_Analysis_of_the_Impact_of_the_Suspension_of_the_M4_Bus_Lane_2012_04_05_

 CAL 182 B 9 M4 Bus Lane The Impact of the Suspension of the M4 Bus Lane Report Q&A

CAL 182 HA AQ Consultation September 2012

CAL 181 M4_Sensitive receptors ie people 201012