Are we keeping up? Accessibility,equity and air quality in regional planning

Many US metropolitan areas have undergone dramatic shifts in socioeconomic organization.. As urban areas gentrify, many low-income residents and communities of color have transitioned towards the exurban periphery. These suburban neighborhoods tend to have fewer employment opportunities and are fairly disconnected from public transportation networks serving the urban core. Using regional transportation plans (RTPs) for three California MPOs, we show that the transportation accessibility and environmental health issues affecting these exurban communities are unique and inadequately captured by the MPOs' current equity metrics. MPOs performance evaluation is regional and achieving equity within the urban core communities will not address emerging equity, accessibility and air quality concerns for exurban communities. With a brief history and a focused case study of RTPs for the San Francisco Bay Area, San Diego, and Fresno, we examine how air pollution, equity, and transportation interact in three different types of 21st century cities. We find that when allocating limited transportation funds, California metropolitan planning organizations (MPOs) prioritize the improvement of existing public transportation in urban core areas over expansion of transit networks towards disconnected exurbs. This approach is an effective way to reduce vehicle miles traveled (and thus, air pollution) at the regional level due to high population concentrations in urban cores. However, this approach also concentrates the air quality benefits of VMT reduction in these same urban core areas. Exurban residents' on-road and near-road exposure to Traffic-Related Air Pollution (TRAP) will not be reduced by improving public transit within the urban core. We argue that although these suburban and exurban communities are a small percentage of the regional population, they have a right to share in the benefits of transportation investments, particularly given the historical and ongoing patterns of displacement and economic exclusion from urban core areas.     

Job accessibility through public transport and unemployment in Latin America: The case of Montevideo (Uruguay)

Accessibility to job opportunities is one of the factors that explains labor outcomes. For developing countries, public transport plays a key role in providing the population with access to employment opportunities. This paper aims to quantify accessibility by public transport to employment in Montevideo, Uruguay and to explore how accessibility to job opportunities via public transport relates to unemployment. To do so, we calculate a cumulative measure of accessibility to job opportunities for 1063 small zones—approximately 4–6 blocks each—within Montevideo. This measure yields accurate data on accessibility and can be assigned to individual households. Accessibility in Montevideo is unevenly distributed among social strata and is concentrated within the central (and wealthier) areas of the city. In addition, a multilevel logistic regression analysis indicates that greater accessibility to jobs via public transport is associated with a lower probability of being unemployed. This finding suggests that improving accessibility to job opportunities via public transit may enhance individual labor outcomes.     

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.     

A random utility maximization (RUM) based measure of accessibility to transit: Accurate capturing of the first-mile issue in urban transit

The paper presents a random utility-based measure of accessibility to explain the first-mile issue in urban transit. A discrete access stop/station location choice model is used to calculate the expected maximum utility of transit access choices as the measure of the proposed access to transit measurement approach. It captures the effects of changes in various personal, sociodemographic, transportation and land-use variables on access to urban transit that are overlooked by conventional approaches of accessibility measurements (count-based cumulative opportunities measures and gravity-based measures). The proposed accessibility to transit measurement approach is empirically measured for the Greater Toronto Area and is integrated into an operational tool programmed in a GIS-based traffic assignment software, TransCAD 7.0. This allows comparing it to the conventional measures, and the results reveal that the conventional measures tend to over-estimate access to transit.     

Investigating socio-spatial differences between solo ridehailing and pooled rides in diverse communities

Transformative mobility services present both considerable opportunities and challenges for urban mobility systems. Increasing attention is being paid to ridehailing platforms and connections between demand and continuous innovation in service features; one of these features is dynamic ride-pooling. To disentangle how ridehailing impacts existing transportation networks and its ability to support economic vitality and community livability it is essential to consider the distribution of demand across diverse communities. In this paper we expand the literature on ridehailing demand by exploring community variation and spatial dependence in ridehailing use. Specifically, we investigate the diffusion and role of solo requests versus ride-pooling to shed light on how different mobility services, with different environmental and accessibility implications, are used by diverse communities. This paper employs a Social Disadvantage Index, Transit Access Analysis, and a Spatial Durbin Model to investigate the influence of both local and spatial spillover effects on the demand for shared and solo ridehailing. The analysis of 127 million ridehailing rides, of which 15% are pooled, confirms the presence of spatial effects. Results indicate that density and vibrancy variables have analogue effects, both direct and indirect, on demand for solo vs pooled rides. Instead, our analysis reveals significant contrasting effects for socio-economic disadvantage, which is positively correlated with ride-pooling and negatively with solo rides. Additionally, we find that higher rail transit access is associated with higher demand for both solo and pooled ridehailing along with substantial spatial spillovers. We discuss implications for policy, operations and research related to the novel insight on how pooled ridesourcing relate to geography, living conditions, and transit interactions.     

A PTAL approach to measuring changes in bus service accessibility

Accessible transport systems are essential to ensure equal opportunities for all people in society. The need for information about transport disadvantage is now a key policy requirement and previous studies have highlighted the need for tools to assess the impact of interventions on the bus network and the accessibility of the system. Geographical Information System (GIS) and ACCMAP enable the analysis of transport disadvantage and accessibility. This paper provides an analysis of the Citybus Network in Northern Ireland and assesses the spatial impact of a hypothetical network change on populations residing within the Citybus network area.     

An innovative transit system and its impact on low income users: the case of the Metrocable in Medellín

The Metrocable in Medellín, Colombia, is an innovative system to improve access to deprived areas located in hilly zones. The idea to use cable cars as feeders to the metro was integrated into an ambitious urban project that, to date, has improved accessibility dramatically for some low-income residents. Using data before and after the project’s implementation, we evaluate the impact on social equity for the population in the zone of influence, considering changes in accessibility to employment and in housing-related costs. The access provided by the project to the main high-employment centres has doubled the number of opportunities that can be reached by the “target population,” even though travel-time savings and costs have seen only small changes. In fact, prior access to the CBD was poor and expensive, but time and costs were reduced with the Metrocable, although this reduction was not equal for all locations in the metropolitan area. In general, we argue that the main benefits, in terms of accessibility that differentiates the areas analysed from those used for comparison, are related to a localised ease of access to specific centres of activity according to the centralised development of the city’s job market along the mass transit lines. In terms of housing costs, we developed a set of difference-in-difference models that considered rent, transport, and public utilities costs; however, none of them have allowed us to conclude that there was a statistically valid relationship between the Metrocable and the changes in costs between the two analysed populations.     

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.     

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.     

A multilevel approach of non-motorised accessibility in disused railway systems: The case-study of the Vasco-Navarro railway

The twentieth century witnessed the closure of many kilometres of railway lines that once came to structure their surrounding territory. Although nowadays many of them are converted in greenways, this paper supports that disused railway lines could also operate as non-motorised transport axes related to daily activities, organising their surrounding territory. In this regard, it is necessary to measure the potential of the line, studying the relations created between the disused line and its surrounding environment by means of non-motorised accessibility analyses. The presented methodology analyses accessibility around a linear system with a multilevel approach: regional, interurban and urban. Each approach provides results of different scales, but in turn provides results of the whole line areas, enabling the comprehension of the potentiality of the infrastructure as a non-motorised axis and the connection with its urban and rural environment. The proposed methodology has been applied in a case study, demonstrating the capability of non-motorised routes to structure the territory and attend several activities, giving rise to more sustainable transport.     

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.     

A flexible framework for measuring accessibility with destination bundling

A transit system's usefulness is governed by the freedom it provides to those who use it. This freedom, typically quantified as accessibility, is proportional to the amount and variety of destinations available to a potential transit user. Often, transit systems are designed with the commuter in mind; employment is a typical stand-in measure for all destinations when measuring accessibility in a city. This paper proposes a framework to “bundle” destination types into a more comprehensive profile of accessibility. The framework is flexible enough to adapt to local conditions and data availability, and provides a potential planner with the ability to tell a more nuanced story of transit accessibility in a city. Using population, employment, and crowd-sourced destination data in Calgary, Canada, we perform a comparison of destination bundling approach to find that the relative level of access to destinations varies greatly with the bundle of destinations used. We also analyze correlations between quality of access to destinations, suggesting that certain destinations can act as substitutes for others, and that using destinations with low correlations in their quality of access increases the results' sensitivity to the transit network. As this approach uses open data sources available in most jurisdictions, it can be easily applied to different urban areas, destination sets, and accessibility measures to tell a more comprehensive story of transit accessibility in cities.     

Making the connections between transport disadvantage and the social exclusion of low income populations in the Tshwane Region of South Africa

To date, the majority of studies which consider transport from a social exclusion perspective have been conducted in the context of the developed world where both income poverty and lack of transport are relative rather absolute states. In a unique departure from these previous studies, this paper explores the relationship between transport and social disadvantage in the development context, the key difference being that income poverty is absolute and where there is much lower access to both private and public transportation generally. Thus, it seeks to explore whether the concept of social exclusion remains valid, when it is the majority of the population that is experiencing transport and income poverty compared with the minority who do so in advanced economies.The paper is based on a scoping study for the Republic of South Africa Department of Transport (RSA DOT), which primarily involved focus group discussions with a range of socially deprived urban and peri-urban population groups living in the Tshwane region of South Africa. In a second departure from previous studies which consider transport and social disadvantage in the development context, the study takes a primarily urban focus. The rationale for this is that theoretically low income urban settlements do not suffer from the lack of transport infrastructure and motorised transport services in the way that more remote rural areas do. The policy issue is therefore less a question of addressing a deficit in supply and more one of addressing particular aspects of public transit service failure, which are more readily amenable to relatively low cost, manageable, small-scale national and local policy interventions.A primary aim for the study was to reinvigorate cross-government debate of these issues in the hope of breaking South African government’s long-standing and persistent policy inertia in the delivery of equitable and socially sustainable urban transport systems.     

Measuring the accessibility and spatial equity of urban services under competition using the cumulative opportunities measure

As accessibility becomes an increasingly relevant concept in the analysis of sustainable transport and urban development, the accuracy of accessibility measures becomes increasingly vital. While more complex measures are gradually gaining popularity with increasing data and computational resources, policy makers and planners are still prone to opt for less complex methods that are easy to use and interpret. The cumulative opportunities measure is the most widely applied accessibility measure in planning practice, but it is also among the least accurate due to its lack of consideration of the impact of competition for those opportunities. This study seeks to highlight the impact of addressing competition for different urban services in the cumulative opportunities measure. A competition component is added to the measure, which is applied to a case study of three types of urban services in the Perth metropolitan area; jobs, primary/secondary education and shopping. The results show that considering competition changes the spatial patterns of accessibility and its equity. Since this approach reveals demand-supply imbalances, it can more accurately determine spatial inequalities in accessibility, and hence increases the utility of the cumulative opportunities measure. We also find that the three services had varying levels and spatial patterns of accessibility and spatial equity, thus relying on any single one of them for assessing spatial structural performance can be misleading.     

Understanding the travel behaviors and activity patterns of the vulnerable population using smart card data: An activity space-based approach

Understanding the travel behaviors and activity patterns of vulnerable people is important for addressing social equity in urban and transportation planning. With the increasing availability of large-scale individual tracking data, new opportunities have emerged for studying people's travel behaviors and activity patterns. However, the data has not been fully exploited to examine the travel characteristics of vulnerable people and their implications for understanding transport-related disadvantage. This study proposes a methodological framework based on the concept of activity space that enables a comprehensive examination of vulnerable people's spatiotemporal travel characteristics and an investigation of the geographies of transport disadvantage. Using the proposed framework, a case study that investigates the bus activities of the vulnerable population using four-month smart card data is carried out in the city of Wuhu, China. The case study suggests that vulnerable people possess distinct travel behaviors that differ considerably from the mainstream population and that the implications of transport disadvantage, as revealed by the participation in bus activities, vary across different demographic groups and across different spatial contexts. Some of the empirical insights obtained from this study also differ from conclusions drawn from previous studies and will enrich our understandings of vulnerable people's activities. Overall, the paper makes two major contributions. Methodologically, the proposed framework can overcome some of the deficiencies of activity space-based approaches for understanding transport disadvantage and contribute broadly to the studies of travel behaviors and activities patterns using individual-level tracking data. Empirically, the study identifies varying spatial and temporal implications of transport disadvantage associated with different vulnerable groups, which could further shed light on public transit planning and service design.     

Analysis of rural activity spaces and transport disadvantage using a multi-method approach

Current knowledge about the relationship between transport disadvantage and activity space size is limited to urban areas, and as a result, very little is known about this link in a rural context. In addition, although research has identified transport disadvantaged groups based on their size of activity space, these studies have, however, not empirically explained such differences and the result is often a poor identification of the problems facing disadvantaged groups. Research has shown that transport disadvantage varies over time. The static nature of analysis using the activity space concept in previous research studies has lacked the ability to identify transport disadvantage in time. Activity space is a dynamic concept; and therefore possesses a great potential in capturing temporal variations in behaviour and access opportunities. This research derives measures of the size and fullness of activity spaces for 157 individuals for weekdays, weekends, and for a week using weekly activity-travel diary data from three case study areas located in rural Northern Ireland. Four focus groups were also conducted in order to triangulate quantitative findings and to explain the differences between different socio-spatial groups. The findings of this research show that despite having a smaller sized activity space, individuals were not disadvantaged because they were able to access their required activities locally. Car-ownership was found to be an important life line in rural areas. Temporal disaggregation of the data reveals that this is true only on weekends due to a lack of public transport services. In addition, despite activity spaces being at a similar size, the fullness of activity spaces of low-income individuals was found to be significantly lower compared to their high-income counterparts. Focus group data shows that financial constraint, poor connections both between public transport services and between transport routes and opportunities forced individuals to participate in activities located along the main transport corridors.     

Informality and accessibility to jobs by public transit: Evidence from the São Paulo Metropolitan Region

Access to opportunities through public transport can have different impacts on individual's life especially in developing countries where opportunities are limited, job informality rates are high, and socioeconomic characteristics gaps are big. The aim of this paper is to explore the relationship between job informality and accessibility to employment by public transport in São Paulo Metropolitan Region (SPMR), Brazil. To do so, we calculate a cumulative-opportunity measure of accessibility to jobs for 633 areas within the SPMR. We use a multilevel mixed-effects logistic regression model to estimate the effect of job accessibility on the likelihood of being informally employed, controlling for individual and other area characteristics. To account for informal sector heterogeneity, two regression models are generated: one for the workers earning below minimum wage and one for the workers earning above minimum wage. The results show that accessibility to jobs is unevenly distributed across the region, largely concentrated in the core of the region, and especially in the high-income areas. The regression results show that for workers earning less than the minimum wage, a higher level of accessibility to jobs by public transport is associated with a lower likelihood of being a worker in the informal job sector. For informal workers earning more than the minimum wage, car ownership seem to be more relevant than transit accessibility in determining the likelihood of being part of the informal job sector. In light of these findings, increasing accessibility by public transport through either expanding transit services to areas with high informality rates to have a better access to formal jobs or supporting the decentralization of formal jobs may be a way to achieve reductions in informality rates, especially among those earning less than the minimum wage.     

基于空间成本分配的北京城市轨道交通票价方案选择评价

成本的空间分配是公共交通公平的重要内容,受不同票价方案影响。为了比较不同票价方案下的空间成本分配差异,运用可达性方法,采用北京地铁及其计程票制数据在城市轨道交通站点间票价的基础上计算区域站均票价,分析不同票价方案下北京区县空间成本分布格局差异,给出区县票价方案择优结果,并对2014年北京城市轨道交通票价听证会选择的票价方案进行评价。结果显示,北京各区县并不适合一种票价方案,各区域有最佳的票价方案选择,选择一种票价方案会导致区域间不公平,为城市轨道交通票价调整政策提供一定的参考。     

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.     

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.