Monitoring the Social Impacts of the Central London Congestion Charge

Monitoring the Social Impacts of the Central London Congestion Charge


A Cairns, Transport for London, UK


This paper will describe the Congestion Charging Social Impacts Monitoring programme, look at how it was developed, the methodology adopted, outline some key results and conclude with a brief look at lessons learnt and the ongoing programme.


The Central London Congestion Charging scheme became operational on 17 February 2003. Changes were forecast to congestion levels and public transport and a range of established methods were used to measure the actual impacts. However, the potential impacts on the day-to-day lives of Londoners were less clear.

Social impacts, positive and negative, would arise from the scheme as a whole, not simply as a result of payment of the charge. Impacts might relate to changes in: local environment; accessibility to services; travel behaviour; mobility; time; finance; and through indirect knock-on effects from other members within households. An early decision was made not to assume what the impacts would be and who they would affect, but rather to discover what they were.

As with all five key areas of the Monitoring Programme the social impacts programme was required to monitor the situation before and after the introduction of the scheme. TfL developed the main programme of research with two academic advisors who specialise in the field of social and transport research and appointed contractors. A range of methodologies were adopted which when considered together provide a comprehensive picture of the impacts.

The most substantial part of the programme involved face to face surveys of respondents in households from a selection of neighbourhoods inside the zone and in inner London and also telephone surveys of individuals living in Outer London and beyond the M25. A panel of these respondents were interviewed both before and after the introduction of the charge.

The data generated by the main surveys allow for a range of analyses, from general comparisons across all respondents by topics, or, pertinent to the methodology, comparisons across geographical areas or by more detail (for example by income, gender, ethnicity, etc.). The format of the ?Before? survey allowed particularly interesting comparison between respondents? expectations of impacts and their experiences of the scheme after charging was introduced.

A key finding was that people were not affected to the extent and magnitude that they had expected to be. Generally more respondents experienced no change and where there was an impact it tended to be more positive than expected, particularly so in Inner and Outer London. The main negative impacts tended to be in relation to changes in social gatherings with friends and family and difficulties in local parking. The main positive experiences tended to relate to reduction in congestion and improved public transport.

There were some results that could have been predicted, for example charging zone residents were most positive about changes to their journeys and their local area, and residents in Inner London made more changes to their journeys into the zone. However, one notable feature of these results was that where there were differences between groups of respondents they were often very variable, not necessarily consistent nor as may have been predicted, for example low income respondents did not find it any more difficult to pay the full charge than other respondents, respondents were less positive generally about their travel experiences than when asked about a specific journey, and there were few differences in overall responses from men and women (usually a common theme in transport studies).

In addition to this a range of other surveys were completed, including focus groups and diary studies to look in detail at certain groups and a number of on-street surveys in selected areas to monitor any changes in the people frequenting those areas, their uses and opinions of it. A general theme within the focus groups was that the charge had worked much better than expected. However, over the longer term they felt that traffic levels had reverted back to their pre-charging conditions and that traffic was worse at the boundary, views not supported by traffic counts. Results of the on-street surveys generally showed no significant change in people using the area, some change in why people were using the area and within the charging zone there was a positive change in people?s perception of that environment, particularly in relation to traffic, noise and air pollution.

By early 2005 these elements of the social monitoring programme were complete, providing the opportunity to further combine analyses and take stock of lessons learnt before planning new programmes. Views on the limitations of the programme varied depending on different requirements and expectations of the data, and tended to relate to the analysis of the data, timescales in producing results, sampling methodology and the inability on occasion to disaggregate the impact of the charge from other background factors. However, there were definite strengths of the programme. There is a new wealth of data, both quantitative and qualitative, on how residents respond to such a traffic scheme and revealing pictures of how households respond to changes that may only directly affect one member. Although perhaps most excitingly there is the opportunity for establishing a large and varied panel over the longer term to allow unprecedented understanding of how impacts might vary over time.


Association for European Transport