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University of Westminster

Transport Studies Group

TSG Research

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:

CAPITAL: re-programming of core tool to enable input of population group specific input values (e.g. maximum walk times, walk speeds), separate estimation of accessibility by different combinations of public transport modes (all modes, all buses, one bus), to reflect different cost constraints and the inability of some groups of people to make certain types of interchange (due to physical or mental limitations); improvements to the presentation of accessibility plots.

PTAM: addition of rail services to the existing bus network data; finer examination of public transport accessibility at specific times of day; addition of bus/bus and bus/rail interchange analysis; cap on waiting times; improved presentation of accessibility plots.

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

WP1: User needs literature review (Acrobat format 1,284k)
WP2: Social groups user needs - survey findings (Acrobat format 2,584k)
WP3: Accessibility analysis literature review (Acrobat format 890k)
WP4: Bus user walk access barriers (Keighley) (Acrobat format 2,411k)
WP5: Bus, DLR/underground walk access barriers (Tower Hamlets) (Acrobat format 3,870k)

WP5 appendix 1: Questionnaire (Acrobat format 1,380k)
WP5 appendix 2: Questionnaire (Acrobat format 1,369k)
WP5 appendix 3: Questionnaire (Acrobat format 1,370k)
WP6: Developing accessibility planning tools (Acrobat format 2,485k)
WP7: Feedback on new/enhanced tools from social groups (Acrobat format 1,182k)
WP7 appendix 1: TH: FG topic guide (Acrobat format 101k)
WP7 appendix 2: TH: Spider map (Acrobat format 271k)
WP7 appendix 3a: TH: CAPITAL map (Acrobat format 178k)
WP7 appendix 3b: TH: CAPITAL map (Acrobat format 202k)
WP7 appendix 3c: TH: CAPITAL map (Acrobat format 195k)
WP7 appendix 3d: TH: CAPITAL map (Acrobat format 132k)
WP7 appendix 4a: TH: Boundary map (Acrobat format 367k)
WP7 appendix 4b: TH: Street Audit map (Acrobat format 366k)
WP7 appendix 4c: TH: Street Audit map (Acrobat format 366k)
WP7 appendix 4d: TH: Street Audit map (Acrobat format 381k)
WP7 appendix 5a: TH: DLR accessibility map: all (Acrobat format 302k)
WP7 appendix 5b: TH: DLR accessibility map: young (Acrobat format 310k)
WP7 appendix 5c: TH: DLR accessibility map: older (Acrobat format 314k)
WP7 appendix 5d: TH: Tube accessibility map: all (Acrobat format 309k)
WP7 appendix 5e: TH: Tube accessibility map: young (Acrobat format 308k)
WP7 appendix 5f: TH: Tube accessibility map: older (Acrobat format 316k)
WP7 appendix 5g: TH: Bus accessibility map: all (Acrobat format 315k)
WP7 appendix 5h: TH: Bus accessibility map: young (Acrobat format 308k)
WP7 appendix 5i: TH: Bus accessibility map: older (Acrobat format 310k)
WP7 appendix 6: K: FG topic guide (Acrobat format 111k)
WP7 appendix 7: K: Bus zone map (Acrobat format 761k)
WP7 appendix 8a: K: PTAM map (Acrobat format 137k)
WP7 appendix 8b: K: PTAM map (Acrobat format 132k)
WP7 appendix 8c: K: PTAM map (Acrobat format 127k)
WP7 appendix 8d: K: PTAM map (Acrobat format 129k)
WP7 appendix 8e: K: PTAM map (Acrobat format 121k)
WP7 appendix 8f: K: PTAM map (Acrobat format 120k)
WP7 appendix 9a: K: Boundary map (Acrobat format 220k)
WP7 appendix 9b: K: Street Audit map (Acrobat format 276k)
WP7 appendix 9c: K: Street Audit map (Acrobat format 278k)
WP7 appendix 9d: K: Street Audit map (Acrobat format 284k)
WP7 appendix 9e: K: Street Audit map (Acrobat format 210k)
WP7 appendix 9f: K: Street Audit map (Acrobat format 211k)
WP7 appendix 9g: K: Street Audit map (Acrobat format 210k)
WP7 appendix 9h: K: Street Audit map (Acrobat format 211k)
WP7 appendix 9i: K: Street Audit map (Acrobat format 271k)
WP7 appendix 10a: B: Accessibility map: all (Acrobat format 264k)
WP7 appendix 10b: B: Accessibility map: young (Acrobat format 275k)
WP7 appendix 10c: B: Accessibility map: older (Acrobat format 278k)
WP7 appendix 10d: B: Accessibility map: female (Acrobat format 266k)
WP7 appendix 10e: B: Accessibility map: male (Acrobat format 266k)
WP7 appendix 10f: B: Accessibility map: restricted mobility (Acrobat format 278k)
WP7 appendix 10g: B: Accessibility map: unrestricted mobility (Acrobat format 267k)
WP7 appendix 10h: R: Accessibility map: all (Acrobat format 259k)
WP7 appendix 10i: R: Accessibility map: young (Acrobat format 251k)
WP7 appendix 10j: R: Accessibility map: older (Acrobat format 275k)
WP7 appendix 10k: R: Accessibility map: female (Acrobat format 272k)
WP7 appendix 10l: R: Accessibility map: male (Acrobat format 271k)
WP7 appendix 10m: R: Accessibility map: restricted mobility (Acrobat format 270k)
WP7 appendix 10n: R: Accessibility map: unrestricted mobility (Acrobat format 272k)
WP8: End of Project Summary Report (Acrobat format 1,742k)


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