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Measuring Accessibility as Experienced by Different Socially Disadvantaged Groups
Contact: Dr. Sarah Wixey
This 2.5 year research project, funded by the Engineering and Physical Sciences Research Council (EPSRC) (Jan 03 - April 05), set out to develop and apply more refined measures of accessibility that are sensitive to the varying perceptions and needs of different social groups. The study sought to capture the ways in which different social groups perceive and use their local environment, covering both strategic-level accessibility (e.g. access to employment opportunities) and micro-level accessibility (e.g. access to local bus stops).
Project partners included Bradford Metropolitan District Council, METRO, the London Borough of Tower Hamlets and Transport for London. The project team have examined local perceptions of accessibility to key services; travel behaviour of different groups compared with national average figures; people's willingness to travel to access services; modes of travel used, barriers to accessibility and people's observations on the utility of existing accessibility model outputs (CAPITAL used by TfL and the Public Transport Accessibility Mapper (PTAM) used by METRO), within two case study areas: parts of the London Borough of Tower Hamlets and Keighley (West Yorkshire).
The research was divided into seven phases, starting with literature reviews of user needs and current accessibility planning concepts and tools, through data collection (both of public attitudes / behaviour and local bus stop / street conditions) to parameter specification and application, and validation of the two enhanced tools among user groups.
The study focused on seven socially disadvantaged groups: young people (16-24), older people (60+), Black and Minority Ethnic (BME) people, disabled people (physically disabled and people with mental health illness), people travelling with young children (aged 11 or under), unemployed people and shift workers.
The results of the initial studies showed, perhaps surprisingly, that very similar concerns were shared across the different age and social groups, despite differences in level of independence, income levels, eligibility for travel concessions and degree of personal mobility. The participants' travel horizons were fairly limited and many people, for whatever reason, tended not to travel outside their local area very often. The boundaries of the area that these individuals are willing to travel within is determined by a combination of their existing experiences, their perceptions, their knowledge, their confidence and the ease with which the journey can be made.
The initial survey work highlighted the need to look in much greater detail at conditions associated with walk access to bus stops and railway stations than had been done in any of the existing accessibility planning tools. A new, free-standing tool was developed by TSG researchers to reflect perceived walk access conditions, called 'WALC' (Weighted Access for Local Catchments). Barriers associated with walk access were found to include: (i) the local terrain (e.g. steep hills); (ii) the lack of provision of seating and a shelter at bus stops; (iii) difficulties in crossing busy roads, due to speeding traffic, heavy traffic volumes, lack of safe crossing points, and barriers (e.g. guard railing) preventing crossing at convenient points; and (iv) low levels of street lighting. Further user surveys were carried out to identify the weights different groups attach to each of these features, and to collect complementary data on physical conditions through street audits in the case study areas.
After discussions with the project partners it was agreed that several enhancements would be made to the existing accessibility tools (CAPITAL and PTAM) including:
The new and modified tools were then presented to respondents in the two case study areas, in focus groups comprising representatives of selected social groups, using examples of outputs relevant to their particular activity and travel needs. To validate the results of the tools, groups were asked about their comprehension of the maps, and to compare the strategic and WALC tool outputs with their own perceptions of accessibility to/from and within their local area.
Participants across all groups showed a clear understanding of the purpose and content of all the accessibility maps, and found them to be comprehendible, relevant and useful. The groups supported the WALC tool's assumption of an unweighted 5 minutes walk time to a bus stop, 8 minutes to a DLR station, or 10 minutes to an underground station, and the approach that had been used for calculating weighted accessibility by type of barrier. Questions were raised about walk speeds (i.e. young people regarded the assumption that they would walk at 4mph as being too high), and about the failure to take full account of the impacts of service reliability (including the ability to board the first vehicle) and some bus connecting times at interchanges, on the realism of some of the outputs - suggesting the need to adjust some parameter values. The validation process has also provided the local authorities with a rich source of data about the concerns of local people living in the area.
SAMP Project Working Papers