How to assess accessibility? : Subjective accounts, objective measurements, or both?
(2018) European Transport Conference- Abstract
- Since the 1990s, researchers have presented compelling links between reduced accessibility, transport disadvantage and social exclusion. This evidence has seen the transport equity policy agenda gain momentum in both the transport research and policy discourses. In tandem with this trend has come an increasing focus on accessibility to out-of-home activities as opposed to realised mobility in terms of observed travel behaviour. Large disparities in accessibility among population groups is a major issue for policymakers concerned with transport equity. As such, transport equity analyses seek to examine the extent to which different population groups can reach and partake in activities considered fundamental for social... (More)
- Since the 1990s, researchers have presented compelling links between reduced accessibility, transport disadvantage and social exclusion. This evidence has seen the transport equity policy agenda gain momentum in both the transport research and policy discourses. In tandem with this trend has come an increasing focus on accessibility to out-of-home activities as opposed to realised mobility in terms of observed travel behaviour. Large disparities in accessibility among population groups is a major issue for policymakers concerned with transport equity. As such, transport equity analyses seek to examine the extent to which different population groups can reach and partake in activities considered fundamental for social inclusion.
However, there is no consensus as to how accessibility as a concept should be defined, nor for how it should be measured. Calculated levels of accessibility using data on land use and the transport system (often referred to as “objective”) require the imposition of the researcher’s values and assumptions which may not necessarily reflect the reality experienced by individuals. Whereas, accessibility analyses based only on people’s accounts (often termed “subjective”) can be problematic in that they can be directly linked to dependence paths and potential self-selection processes. This makes it difficult to analyse the distribution of circumstances across population groups. A combination and comparison of the two kinds of accounts could provide a more reliable picture of accessibility.
This study encompasses a focus on both a subjective and objective measurement of accessibility; the former comprising individuals’ own perceptions of their capability to access valuable out-of-home activities, and the latter, a composite measure of individual activity-based accessibility. The aim of this study is three-fold: (1) To more accurately represent individual accessibility by combining both objective and subjective accounts; (2) To examine the distribution of these two accounts; and (3) To analyse whether and how these two accounts differ. And, if they do differ, are there systematic mechanisms behind these differences?
The individuals’ perceptions of their circumstances were obtained through a quantitative telephone survey comprising 1,149 computer-assisted telephone interviews (CATI) with a random sample of people aged 65-79 and living in Sweden’s large metropolitan regions: Stockholm, Gothenburg and Malmö. The objective measurement was then developed using a composite measure of accessibility to key activities. This was developed using impedance measurements (the shortest distance and travel-time by several modes and combinations of modes) to a typology of key activities. This typology comprises two kinds of activities, termed “necessary” and “desired”. The geo-locations of such activities were obtained using land use data from Open Street Maps, official databases provided by Statistics Sweden, a national database of supermarkets and grocery stores and three regional databases of health centre geo-locations. Travel-times were calculated using multimodal transport modelling with OpenTripPlanner,
ETC 2018 Abstract Submission
Young Researchers and Practitioners Forum
road network data from OpenStreetMap and public transport data organised in General Transit Feed Specification (GTFS) format provided by Trafiklab in Sweden.
Spatial regression models will be used to analyse how these two accounts differ: what is overlooked by just focusing on either objective or subjective accessibility? What do we gain by taking both into account? Four groups of respondents can be identified: (1) those with both reported and observed accessibility to activities; (2) those with neither; (3) those with reported accessibility but not observed; and (4) those with observed accessibility but not reported. These groups will be analysed using factor analysis techniques and a multivariate multinomial logistic regression model.
The results of this study will allow us to gain a greater insight into the ways in which the two accounts can complement one another and the distribution of both “subjective” and “objective” accessibility among this group. Exploring the differences between the two accounts will help us to uncover potential reasons as to why subjective and objective measurements can differ and how such methodological difficulties can be overcome. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/9869e2d2-21ed-4e71-9a29-608870bf6659
- author
- Ryan, Jean LU and Pereira, Rafael H. M.
- organization
- publishing date
- 2018-10-12
- type
- Contribution to conference
- publication status
- published
- subject
- conference name
- European Transport Conference
- conference location
- Dublin, Ireland
- conference dates
- 2018-10-10 - 2018-10-12
- language
- English
- LU publication?
- yes
- id
- 9869e2d2-21ed-4e71-9a29-608870bf6659
- date added to LUP
- 2019-06-18 10:40:17
- date last changed
- 2019-06-27 14:54:13
@misc{9869e2d2-21ed-4e71-9a29-608870bf6659,
abstract = {{Since the 1990s, researchers have presented compelling links between reduced accessibility, transport disadvantage and social exclusion. This evidence has seen the transport equity policy agenda gain momentum in both the transport research and policy discourses. In tandem with this trend has come an increasing focus on accessibility to out-of-home activities as opposed to realised mobility in terms of observed travel behaviour. Large disparities in accessibility among population groups is a major issue for policymakers concerned with transport equity. As such, transport equity analyses seek to examine the extent to which different population groups can reach and partake in activities considered fundamental for social inclusion.<br/>However, there is no consensus as to how accessibility as a concept should be defined, nor for how it should be measured. Calculated levels of accessibility using data on land use and the transport system (often referred to as “objective”) require the imposition of the researcher’s values and assumptions which may not necessarily reflect the reality experienced by individuals. Whereas, accessibility analyses based only on people’s accounts (often termed “subjective”) can be problematic in that they can be directly linked to dependence paths and potential self-selection processes. This makes it difficult to analyse the distribution of circumstances across population groups. A combination and comparison of the two kinds of accounts could provide a more reliable picture of accessibility.<br/>This study encompasses a focus on both a subjective and objective measurement of accessibility; the former comprising individuals’ own perceptions of their capability to access valuable out-of-home activities, and the latter, a composite measure of individual activity-based accessibility. The aim of this study is three-fold: (1) To more accurately represent individual accessibility by combining both objective and subjective accounts; (2) To examine the distribution of these two accounts; and (3) To analyse whether and how these two accounts differ. And, if they do differ, are there systematic mechanisms behind these differences?<br/>The individuals’ perceptions of their circumstances were obtained through a quantitative telephone survey comprising 1,149 computer-assisted telephone interviews (CATI) with a random sample of people aged 65-79 and living in Sweden’s large metropolitan regions: Stockholm, Gothenburg and Malmö. The objective measurement was then developed using a composite measure of accessibility to key activities. This was developed using impedance measurements (the shortest distance and travel-time by several modes and combinations of modes) to a typology of key activities. This typology comprises two kinds of activities, termed “necessary” and “desired”. The geo-locations of such activities were obtained using land use data from Open Street Maps, official databases provided by Statistics Sweden, a national database of supermarkets and grocery stores and three regional databases of health centre geo-locations. Travel-times were calculated using multimodal transport modelling with OpenTripPlanner,<br/>ETC 2018 Abstract Submission<br/>Young Researchers and Practitioners Forum<br/>road network data from OpenStreetMap and public transport data organised in General Transit Feed Specification (GTFS) format provided by Trafiklab in Sweden.<br/>Spatial regression models will be used to analyse how these two accounts differ: what is overlooked by just focusing on either objective or subjective accessibility? What do we gain by taking both into account? Four groups of respondents can be identified: (1) those with both reported and observed accessibility to activities; (2) those with neither; (3) those with reported accessibility but not observed; and (4) those with observed accessibility but not reported. These groups will be analysed using factor analysis techniques and a multivariate multinomial logistic regression model.<br/>The results of this study will allow us to gain a greater insight into the ways in which the two accounts can complement one another and the distribution of both “subjective” and “objective” accessibility among this group. Exploring the differences between the two accounts will help us to uncover potential reasons as to why subjective and objective measurements can differ and how such methodological difficulties can be overcome.}},
author = {{Ryan, Jean and Pereira, Rafael H. M.}},
language = {{eng}},
month = {{10}},
title = {{How to assess accessibility? : Subjective accounts, objective measurements, or both?}},
year = {{2018}},
}