Assessing equity in transport accessibility to work and study: The Bogotá region

This research was aimed at exploring levels of equity in accessibility to employment and education in the city-region of Bogotá, Colombia's capital city. Building on consolidated methodologies for the assessment of potential accessibility, we estimate accessibility indicators at the zone level, evaluate how potential accessibility varies among income groups, and present evidence related to transport mode, in order to analyze social and spatial inequalities produced by the distribution of accessibility to employment and education activities. The research incorporates a method to evaluate how accessibility varies among zones according to average income and mode of transport in order to produce evidence-based arguments that can inform transport policy in the city-region of Bogotá, and other similar contexts in the Global South. Our results show strong distributional effects of the socio-spatial and economic structure of the city-region, its transport infrastructure and services, and the effect of current transport and land-use policies for citizens of different income groups. The tools and empirical evidence in this research seek to contribute to informed policy development in Latin America and other developing contexts, and feeding current debates on the role of accessibility in addressing social and spatial inequalities stemming from urban mobility.     

Accessibility modelling: predicting the impact of planned transport infrastructure on accessibility patterns in Edinburgh,UK

The achievement of good spatial accessibility and equity in the distribution of urban services is one of the supreme goals for urban planners. With Scottish Government backing, the City of Edinburgh Council (CEC) has started to construct a tram network to cater for the future needs of Scotland’s capital city by providing an integrated transport solution using trams and buses. Spatial Network Analysis of Public Transport Accessibility (SNAPTA) which is a GIS-based accessibility model has been developed to measure the accessibility by public transport to different urban services and activities. The model responds to several limitations in other existing accessibility models in planning practice. It offers an alternative and practical tool to help planners and decision makers in examining the strengths and weaknesses of land use – transport integration. SNAPTA has been applied to a pilot study in Edinburgh city to identify the contribution of the infrastructure improvements of the tram system and Edinburgh South Suburban Railway (ESSR) to improved accessibility by public transport to six types of activity opportunities. This paper outlines the concept and methodology of the SNAPTA model, and presents the findings related to this pilot study with a focus on changes in potential accessibility to jobs between four different public transport network scenarios. The accessibility values so obtained help to identify the gaps in the coverage of the public transport network and the efficiency in the spatial distribution of urban services and activities. The findings focus on whether the planned transport infrastructures for Edinburgh will lead to better accessibility and reduced inequity (in terms of accessibility) across the city.     

Perceived accessibility: What it is and why it differs from calculated accessibility measures based on spatial data

Accessibility is usually evaluated using indicators calculated from spatial data. However, perceived accessibility, defined as the perceived potential to participate in spatially dispersed opportunities, is often poorly reflected by these calculated measures. This paper sets out to explain the mechanisms that lead to these mismatches. A conceptual model is constructed to establish what factors shape perceived accessibility. A schematic framework shows that mismatches between a calculated indicator and perceptions can stem from inaccuracies in awareness as well as from inaccuracies in the measure if the measure fails to take account of the subjective evaluations of accessibility components. When evaluating the performance of land-use and transport system configurations, calculated measures based on spatial and transport data only serve as proxies for how accessibility is actually experienced. This paper argues that bringing perceived accessibility to the fore of accessibility-based planning, by acknowledging and evaluating potential mismatches with calculated accessibility indicators, will advance the evolution from mobility-based to accessibility-based planning.     

Public transport accessibility accounting for level of service and competition for urban opportunities: An equity analysis for education in Santiago de Chile

Several cities around the world have changed their transportation planning paradigm, understanding that the prime goal is to provide access to opportunities for everyone. To address this goal, public transport plays a fundamental role and, therefore, it is key for developing a sustainable and equitable city.This paper proposes a methodology to analyze access to opportunities through public transport incorporating the user's valuation of attributes that impact the level of service on his/her trip and the competitiveness for urban opportunities. Using data from Santiago, Chile, we applied the proposed methodology to analyze accessibility to higher-quality public primary schools. We compare total travel time (TTT) with a proposed measure of total generalized travel time (TGTT) using simple potential and competitive accessibility indicators, accounting for the subjective valuation of walking time, travel time, waiting time, comfort and transfers, and translating them into in-vehicle time units.We find that the inclusion of competition has a more substantial impact than including the subjective valuation of the level of service in the accessibility to educational opportunities. Using competitive measures with TGTT, we found that around 20% of the zones in Santiago have at least a 50% deficit of higher-quality public education, and 71% of them are in peripheral areas. Furthermore, these zones, where medium and low-income population usually lives, can experience, on average, 1–2 transfers, 4–5 passengers per square meter, and 15-min waiting. We conclude that the proposed methodology provides a more comprehensive way to understand accessibility by incorporating the traveling experience, allowing to determine how and where to intervene to effectively improve accessibility, with a focus on urban equity.     

Analysing transport corridor policies: An integrative approach to spatial and social disparities in India

Although strategies to create transport corridor are prevalent in the global South, there is a lack of empirical research to evaluate these initiatives, in particular whether they have realised their general goal of reducing regional disparities. The current paper describes a multi-method approach involving spatial and non-spatial analysis to investigate spatial disparity along a proposed corridor and examine its integration within the existing settlement structure. The analytical framework is tested on India’s Delhi-Mumbai Industrial Corridor. A rationale is developed to enable a critical view of corridor policies as strategies for development in the global South.One important finding regarding policies on transport corridors is the risk that future growth will remain concentrated in districts directly linked to a proposed corridor, leaving peripheral areas marginalised. An integrative analysis of current spatial and social disparities in India shows growth to be high in areas with good accessibility between urban and rural areas. Specifically, growth in rural areas is fostered by the availability of good road network, and polytechnic and vocational institutions, whereas in urban areas, growth is positively associated with the provision of secondary schools. In order to prevent or even reduce disparities, this research recommends that spatial strategies be developed with mechanisms to enable their implementation by lower tiers of governments, that spatial plans and infrastructure outlays be reformed to improve accessibility between proposed corridors and peripheral areas, and that accessibility indicators be included in the design and implementation of transport development policies.     

E-shoppers and multimodal accessibility to in-store retail: An analysis of spatial and social effects

Amidst the growing interest in enhancing the academic understanding of the relationships between e-shopping and transport, a key element remains underexplored – the impact of e-shopping on spatial accessibility to in-store retail. The paper studies variations in multimodal accessibility to in-store retail between e-shopper groups and the associated spatial effects. The research is based on a face-to-face questionnaire, administered in the city of Alcalá de Henares (Madrid Metropolitan Area, Spain), which provides data on socio-economic characteristics, e-shopping habits, and travel time preferences to reach in-store retail. Clustering techniques serve to identify three e-shopper groups: occasional e-shoppers with a car, infrequent e-shoppers with a car, and frequent e-shoppers without a car. A comparison of e-shopper distance-decay functions to reach in-store retail is made, revealing significant differences between the three e-shopper groups for car and public transport for any time interval. However, for walking such differences are limited to time intervals between 10 and 40 min. Distance-decay functions are processed through a gravity-based model, identifying five categories of multimodal accessibility places that provide information on how in-store retail locations may be affected by e-shopping habits. The paper closes with concluding remarks on policy-making and a few pathways for future research.     

Spatio-temporal evolution of cities and regional economic development in Nepal: Does transport infrastructure matter?

The literature on the New Economic Geography (NEG) suggests that transport cost is a major driving factor for the emergence of core–periphery patterns within a country. However, very few studies have tested this theoretical explanation in the context of transport infrastructure networks in developing countries. This paper takes a closer look at Nepal and tests four expectations that are drawn from the NEG, which highlight different aspects of the formation of core–periphery dynamic as determined by infrastructure quality. The expectations are tested by relating spatial-temporal patterns of road development to the growth and distribution of cities and examining the transport infrastructure contribution to shaping the patterns of regional economic development. We used intercity travel time estimates, based on the design speed of roads, length of sections and pavement type (from 1961 onwards in 10-year segments) as an indicator for the quality of infrastructure (transportation cost). Next, we computed hubness and accessibility indices of cities, defined by means of a gravity model and as a function of transportation cost, to undertake a cross-city comparison. We applied GIS mapping, multiple regression and mediation analysis techniques to relate these transport and accessibility characteristics to spatio-temporal patterns in city size and GDP per capita. Our study broadly confirms the core expectation derived from the NEG that transport improvements facilitate urbanization and that higher urbanization leads to higher regional GDP per capita. Two independent effects were identified in qualification of these overall patterns – the impact of market potential on city primacy and the impact of highly localized, immobile resources on GDP.     

Fair accessibility – Operationalizing the distributional effects of policy interventions

A fair distribution of public transport benefits is a commonly stated goal of agencies and operators of public transport. However, it is less complicated and costly to provide accessibility in some parts of cities and their surroundings than in other parts. Densely populated areas, and areas situated closer to the city center therefore often have higher public transport accessibility than remote or sparsely populated areas. Neglecting these realities results with an unrealistic assessment of equity in service provision and hampers their consideration when setting policy goals. In this study, we propose a framework for investigating equity in the distribution of accessibility, where the suggested goal is to provide residents with equal accessibility for equally dense and central areas. For the Stockholm County, we show that accessibility may seem to be distributed horizontally inequitable and vertically regressive. However, once controlling for how dense and close to the city center residents live, while still being horizontally inequitable the distribution of accessibility in Stockholm County is found progressive, i.e., benefiting those with lower incomes. We demonstrate the proposed method for the case of skip-stop train operations and find that it shifts our constructed accessibility measure toward a more horizontally inequitable and vertically progressive state. We conclude that our proposed method can be a potent way for public transport agencies to measure and concretize equity goals and evaluate policy changes.     

Grocery store accessibility: Different metrics – Different modal disparity results and spatial patterns

Most accessibility studies focus on within transport mode travel performance variations. However, modal accessibility disparity analysis adds value to the single-mode analysis by assessing the interaction between different transport modes and land use. A review of modal disparity studies shows that different accessibility metrics lead to different results, and so it is unclear how this impacts modal accessibility disparity variation. Moreover, the correspondence of the disparity spatial pattern between the different metrics is unclear. This research examines how three typical accessibility metrics (closest facility, cumulative opportunity, space-time constrained) impact modal disparity of grocery store accessibility in Warsaw, Poland. Further, local indicators of spatial association are used to identify areas of similarity and difference between the metrics. This study finds that cumulative opportunities during non-rush hours indicate the best car advantage for all travel times but indicate the best transit advantage during rush hours for 15 min. Generally, the space-time metric indicates better transit accessibility than the closest facility metric which in turn shows better transit accessibility than cumulative opportunities. The city center has significant spatial similarity while peripheral, especially dense, areas have significant spatial difference. Similarity areas have higher transit stop and population densities, while difference areas have average-to-low stop, population, road and store densities.     

Extending public transit accessibility models to recognise transfer location

A longstanding issue for public transit agencies has been how to assess the performance of transit service including spatial service coverage to meet the transport needs of the community. The conventional approach quantifies accessibility using door-to-door travel time in such a way that accessibility declines as the travel time to the opportunity increases. A new approach to modelling transit accessibility is proposed by incorporating the potential effect of transfer location. It builds on the premise that transit users may have a preference for a transfer location best located relative to the trip origin and destination points. The model is tested in Brisbane's bus network which has a radial form, where inner-city suburbs have relatively higher accessibility than outer-city suburbs, if only travel time is counted. Incorporating the transfer location refines the accessibility modelling so that some outer-city suburbs located along the major bus corridors have a relatively higher accessibility level. The new model also suggests that inner-city suburbs do not necessarily have better accessibility. Suburbs close to the city centre may have shorter transit travel time to reach other suburbs, but they do not have a well-connected transit network to other suburbs through service transfers.     

A GIS-based spatial statistical approach to modeling job accessibility by transportation mode: case study of Columbus,Ohio

Improving job accessibility based on transport connectivity helps to address equity issues. Spatial autocorrelation (SA) is also a focus of interest in transportation planning, but has been neglected in analyzing job accessibility in metropolitan areas. In this study, GIS-based job accessibilities by walking, transit, and car are computed for the metropolitan area of Columbus, Ohio, and three transport-based spatial autoregressive (SAR) models are estimated to account for the SA of job accessibility among neighboring block groups, while controlling for built-environment and socioeconomic factors. SA intensities and extents are compared in order to better understand local spatial clusters of job accessibility across the region. Direct and indirect spillover effects due to an investment change in transportation facilities are estimated and provide important transportation planning information. The results also show that walking-accessed jobs are primarily related to physical settings (e.g., land uses) at the local level. Locations with a higher share of zero-vehicle housing units have better job accessibility by transit. There is a spatial mismatch between Asian population clusters and transit-accessed jobs, possibly because of the car-oriented residential clusters around Honda of America Manufacturing in suburban areas. More importantly, locations with a higher share of single-parent households are at a disadvantage in overall job accessibility. Due to its complex transportation needs, a society friendly to single parents should spatially integrate accessible jobs with other needed activities via land-use and transportation planning. Alternatively, car-ownership programs and non-spatial social supports also might be effective to help secure job opportunities and perform daily life activities.     

The impact of the great recession on Irish air travel: An intermodal accessibility analysis

This paper quantifies the changes in accessibility at small area scale arising from the combined effects of dramatic air traffic declines and a greatly expanded motorway network in Ireland during the period of the great recession. The subsequent policy decisions by government are assessed in light of the intermodal accessibility changes identified. The Irish Government engaged in an extensive motorway construction programme throughout the 2000s, greatly increasing the overall length of the inter-urban motorway network. The essential air transport services programme put in place in the 1990s to guarantee a minimum level of air access to disadvantaged regions was significantly reduced at the end of the 2008–2011 period, with only two of the six regional airports continuing to have any form of subsidised public service obligation for the period 2011–2014. In this study, small area datasets are used to measure the net impact of these changes on air transport accessibility in Ireland and the potential spatial inequalities that arise as a result of these changes. An inter-modal accessibility approach is used where the physical characteristics of the road transport network to airports and the network structure characteristics of the air transport system are taken into account to evaluate the levels of air transport accessibility at the small-area district level. Results from the analysis show that the improved surface access to the larger Irish airports (Dublin and Belfast) has enhanced the range of European and global locations directly accessible by air for many communities in Ireland. The net effect of these changes has been to concentrate air traffic at the largest Irish airports.     

Rebuilding women's livelihoods strategies at the city fringe: Agency,spatial practices,and access to transportation from Semmencherry,Chennai

Existing debates suggest that resettlement leads to exclusion of the urban poor from the city, linked to interrupted livelihoods and lack of accessibility to the city. This paper analyses the ways in which public transport mobility plays a role in the livelihood strategies of women living in a resettlement area at the fringe of Chennai, India. The main question addressed is how women exercise agency in embedding spatial practices within their livelihood strategies to reconnect to the city.The analysis is based on 4 months fieldwork in Semmencherry Resettlement Area in Chennai (India). It combines a qualitative analysis with a spatial exploration drawing on concepts from debates on the livelihoods approach, spatial practices, and accessibility and transport-related exclusion. Results show that the more agency women have to negotiate livelihoods strategies, the better they can take complex decisions on accessing resources over large distances and minimizing their adverse effects.We argue that combining a livelihood with a spatial analysis is important because it shows how spatial exclusion has to be assessed according to women's own priorities and decisions concerning spatial practices as part of livelihoods strategies. Accessibility and recreating relational spaces may both widen women's opportunities as well as overstretch their physical and financial resources.     

Population change and accessibility by road and rail networks: GIS and statistical approach to Finland 1970-2007

This study analyzes the relation of accessibility by road and railway network to population change between the years 1970-2007 in Finland. Accessibility is evaluated at built-up area unit and municipal levels by potential accessibility analysis and by measuring accessibility to network. Analyses are done in decadal periods by using geographical information systems (GIS) and data about road and railway networks involving digitized speed limits and geometry for each period. Accessibility variables and population change are related by generalized additive models (GAMs). The results indicate that the Finnish population has concentrated to areas with high road-based potential accessibility, especially since the opening in the Finnish economy in the 1990s. The accessibility of railway network was found to have affected the population change in the 1970s, when local level traffic reduced in the entire country, and in 2000-2007, following remarkable investments in long-haul transport.     

Access to the city: Mobility patterns,transport and accessibility in peripheral settlements of Dar es Salaam

This paper is concerned with access to the city for urban residents living in the periphery of Dar es Salaam, Tanzania. The paper presents an analysis of the mobility practices of residents and investigates the mobility constraints they experience in relation to the limited accessibility provided by the urban transport system. The paper draws upon qualitative interviews with residents in the periphery as well as recently collected travel speed data and offers a unique combination of testimony with GIS-based modelling of overall accessibility. A central finding is the overall importance of regular mobility and access to the city for residents in the periphery. Regular mobility is an ingrained part of residents' livelihood strategies. The majority of households rely on one or more members regularly travelling to central parts of the city in relation to their livelihood activities. The analysis reveals a widespread, near-to-universal, dependence on motorized transportation, with the vast majority depending on public transport. Raster-based modelling of overall accessibility provides an indication of the very high travel times endured by residents in the periphery. The analysis identifies and distinguishes between three overall mode types: 1) Private car, 2) public transport and 3) motorcycle/car combined with public transport. While private cars appear marginally faster, differences in travel times are actually limited. This suggests that travel times are less influenced by mode of transport than by road and traffic conditions and highlights how accessibility problems of peripheral settlements are not easily understood separately from the general dysfunctions of the overall mobility system of city.     

Measuring relative non-motorized accessibility to retail activities

Accessibility planning is a crucial alternative to mobility planning for reaching sustainable outcomes. Although there is a vast literature on accessibility, less attention is paid to accessibility as a relative concept, i.e., its relationship with the socio-economic characteristic of the population. While accessibility is known to vary by location, it also changes as a consequence of differences in individual willingness to reach destinations by certain transport modes. Using the city of Zaragoza, Spain as a case study, this paper evaluates relative non-motorized accessibility (walking and cycling) to three types of retail activities: daily, weekly, and incidental. First, a clustering process is used to identify four population groups according to their socio-economic characteristics (the young employed; the young unemployed; seniors and adults). Second, distance-decay functions based on time-willingness to reach retail destinations by non-motorized modes are compared between the four clusters of population. Third, relative accessibility maps based on gravity-based models are elaborated, highlighting places that exhibit statistical differences between the population clusters. The results indicate that willingness to reach retail stores on foot by seniors (>65?years old) was significantly different from the rest of groups analyzed, providing additional insights on how relative accessibility measurements can anticipate potential social exclusion risks.     

Population growth,accessibility spillovers and persistent borders: Historical growth in West-European municipalities

Lack of cross-border transport supply has repeatedly been blamed for the fact that national borders limit spatial interaction and, consequently, the growth of border regions. This study applies an accessibility approach to investigate for most municipalities in ten countries in mainland West Europe if foreign transport supply is lagging behind, and if population growth in these municipalities has been affected by the limits that national borders have imposed on market access. To do so, data describing historical population changes and road networks between 1961 and 2011 have been used. The results show that in the study area, cross-border transport accessibility was not at a disadvantage in 1961 and has since then grown even more than domestic accessibility. However, municipal population growth has depended almost exclusively on domestic market access. Processes of economic international integration in the study area are found to coincide with the growth of cross-border accessibility, but do not have a clear coincidence with the effects of cross-border accessibility on population growth.     

Transit Deserts: Equity analysis of public transit accessibility

Areas, where disadvantaged and transit-dependent populations are provided with inadequate amounts of transit supply, can be labeled transit deserts. Exploring transit deserts may help transit agencies improve accessibility to services while improving transit distribution and equity. This study utilizes the concepts of transit demand and transit supply to identify transit deserts in the City of Dallas. The comprehensive public transit accessibility (CPTA) score is introduced to evaluate accessibility to transit and to provide a holistic view of transit supply. While previous studies have primarily used proximity or spatial indicators to describe accessibility, this study utilizes a comprehensive set of spatial and temporal measures (connectivity to the network, connectivity to destinations, service frequency, flexibility, and time efficiency) to estimate accessibility to transit. Overlapping areas of high demand (transit dependency) and low supply (as measured using the CPTA) are then characterized as transit deserts. The CPTA score and its application to the analysis of transit deserts provides a universal framework which can be broadly applied by transit agencies, city officials, and transit stakeholders. The contributions of this study are as follows: first, developing a comprehensive framework to estimate transit supply or accessibility; and second, introducing a methodology for identifying transit deserts.     

Understanding accessibility through public transport users' experiences: A mixed methods approach

The quantitative measurement of accessibility through public transport has become more complex and accurate over time. However, it lacks many of the deeper nuances of how people actually experience their travel environments. Our previous works have highlighted the importance of incorporating the lived travel experiences of passengers within accessibility indicators, considering the quality of the walking environment and different attributes of the public transport services.Building on these works, this mixed-method research seeks to further improve the characterization of accessibility according to users' travel experiences, as described by those attributes that inhibit or enhance access to opportunities within the city. We use content analysis of focus groups, data gathered in a brief survey and sociodemographic and public transport data for our analyses. Our main contributions are (i) to develop a conceptual framework to analyze qualitative data on how people relate and discuss their public transport accessibility experiences and (ii) to develop accessibility indicators differentiating user perceptions. We apply this novel conceptual framework and methods to the unique urban morphology of two municipalities of Santiago de Chile.We identified different ‘socially constructed’ narratives for buses and metro. The participants focused on barriers to accessibility, showing an important relationship between them, as well as substantial differences in their overarching positive perception of metro and negative for buses. However, when disaggregating the analysis by primary transport mode and location, we found ‘hidden’ values for buses, recognizing its capillarity and underlying connectivity with the metro system. Furthermore, we found a dissimilar perception of transport environments when disaggregating the analysis by gender, age and location, which translated into different accessibility profiles for the various public transport users. From these experiential qualitative perspectives, it was thus possible to determine some attributes that had been previously overlooked in more quantitative studies but which are important when analyzing public transport accessibility for different population groups.