25 February 2022


Traffic management measures help to avoid air pollution episodes

An investigation of the potential role of temporary urban access control as a means of controlling poor air quality is just one of the topics covered in a recently published report entitled “Assessment of Traffic Management During High Pollution Episodes”. Aimed at a wide audience in the air quality and traffic management communities, the document considers a number of options for avoiding or mitigating periods of very high air pollution levels.

The report details the practical, administrative and cost implications of introducing a number of different traffic management approaches, ranging from voluntary, information-based techniques right through to more draconian temporary zonal access control. Additionally, the requirements of these techniques for short and long-term information dissemination is set out in detail. Most importantly, an assessment of the effects of the measures on emissions and air quality has been carried out, using traffic modelling and air quality modelling techniques based around two English local authorities. The report also draws on work undertaken in the two high-profile examples of Paris and Rome where pollution-responsive measures have been implemented.

The report marks the culmination of a project which is one of a number commissioned under the Department for Transport, Local Government and the Regions’ TRAMAQ (Traffic Management and Air Quality) Programme.

The project provides local authorities in the UK with information and advice which will enable them to select the most appropriate traffic management systems for reducing vehicle movements before and during high pollution episodes, either through enforced or voluntary restrictions. The project team, comprising Transport & Travel Research Ltd (TTR) and TRL Ltd, has previously examined the systems, including infrastructure, funding mechanisms and technologies, which are in operation in other countries and assess which of these can best be adapted for the UK context.

The report is available now from TTR’s Bristol office Tel: 0117 907 6520, email: [email protected] Prices are £20 for hard copy and £10 for an electronic version supplied in PDF format on CD-ROM, including postage. Executive summaries are also available.

The literature review carried out in the project, and detailing overseas experience, is available from TRL as Report No. TRL459. Email [email protected] or visit www.trl.co.uk

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For more information, please contact:


Guy Hitchcock / Paul Davison at TTR

tel: 0117 907 6520



1.        TRL Ltd is an independent, internationally recognised centre of excellence in surface transport issues. For more than 60 years TRL has worked closely with customers in the public, private and independent sectors of the UK and worldwide. The organisation provides research based technical help, which enables customers to obtain improved value for money, generate competitive advantage and a better understanding of transport problems.

2.        TRAMAQ is a six year programme of research commissioned by the Charging and Local Transport (CLT) division of the Department for Transport, Local Government and the Regions (DTLR) to research the effects of traffic management schemes on air quality and/or vehicle emissions. It began in 1998 and currently is due to be completed by 2004/5. The intention is to provide local authorities with technical advice and guidance so that they can better assess the effects of traffic management on air quality in urban areas.