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.     

Accessibility and Transit-Oriented Development in European metropolitan areas

This study investigates how urban form is related to accessibility. In particular, it explores the relationship between Transit-Oriented Development (TOD) and rail-based accessibility in a metropolitan area. The following overarching questions are addressed: Does a TOD-informed urban spatial structure correlate with high rail based accessibility? Which features of TOD are correlated to rail-based accessibility? These questions are answered through a comparative analysis of six metropolitan areas in Europe. The “TOD degree”, operationalized as the extent to which urban development is concentrated along rail corridors and stations, is correlated with a cumulative opportunity measure of rail-based accessibility to jobs and inhabitants.The comparison demonstrates that rail-based accessibility is higher in urban areas where inhabitants and jobs are more concentrated around the railway network and in lesser measure in urban areas with higher values of network connectivity. No correlation is found between rail-based accessibility and average densities of inhabitants and jobs.     

Accessibility across transport modes and residential developments in Nairobi

A key goal of urban transportation planning is to provide people with access to a greater number of opportunities for interaction with people and places. Measures of accessibility are gaining attention globally for use in planning, yet few studies measure accessibility in cities in low-income countries, and even fewer incorporate semi-formal bus systems, also called paratransit. Drawing on rich datasets available for Nairobi, Kenya this analysis quantifies place-based accessibility for walking, paratransit, and driving using three different measures: a mobility measure quantifying how many other locations in Nairobi can be reached in 60 min, a contour measure quantifying the number of health facilities that can be reached in 60 min, and a gravity measure quantifying the number of health facilities weighted by a time-decay function. Health facilities are used because they are an essential service that people need physical access to and as a representation of the spatial distribution of activities more broadly. The findings show that place-based accessibility is highest for driving, then paratransit, then walking, and that there are high levels of access to health facilities near the Central Business District (CBD) for all modes. Additionally, paratransit accessibility is comparatively better in the contour and gravity measures, which may mean that paratransit is efficiently providing access based on the spatial distribution of services. The contour measure results are also compared across different residential levels, which are grouped based on neighborhood characteristics and ordered by income. Counterintuitively, the wealthiest areas have very low levels of place-based accessibility for all modes, while poor areas have comparatively better walking access to health facilities. Interestingly, the medium low residential level, characterized in part by tenement apartment buildings, has significantly higher accessibility than other residential types. One way to reduce inequality in access across income groups is to increase spatial accessibility for the modes used by low- and middle-income households, for example with policies that prioritize public transport and non-motorized travel, integrate paratransit with land use development, and provide safe, efficient, and affordable options.     

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.     

Measuring and visualizing place-based space-time job accessibility

Place-based accessibility measures, such as the gravity-based model, are widely applied to study the spatial accessibility of workers to job opportunities in cities. However, gravity-based measures often suffer from three main limitations: (1) they are sensitive to the spatial configuration and scale of the units of analysis, which are not specifically designed for capturing job accessibility patterns and are often too coarse; (2) they omit the temporal dynamics of job opportunities and workers in the calculation, instead assuming that they remain stable over time; and (3) they do not lend themselves to dynamic geovisualization techniques. In this paper, a new methodological framework for measuring and visualizing place-based job accessibility in space and time is presented that overcomes these three limitations. First, discretization and dasymetric mapping approaches are used to disaggregate counts of jobs and workers over specific time intervals to a fine-scale grid. Second, Shen's (1998) gravity-based accessibility measure is modified to account for temporal fluctuations in the spatial distributions of the supply of jobs and the demand of workers and is used to estimate hourly job accessibility at each cell. Third, a four-dimensional volumetric rendering approach is employed to integrate the hourly job access estimates into a space-time cube environment, which enables the users to interactively visualize the space-time job accessibility patterns. The integrated framework is demonstrated in the context of a case study of the Tampa Bay region of Florida. The findings demonstrate the value of the proposed methodology in job accessibility analysis and the policy-making process.     

Evaluating the equity implications of ridehailing through a multi-modal accessibility framework

In rapidly-growing metropolitan regions, it is crucial that transportation-related policies and infrastructure are designed to ensure that everyone can participate equitably in economic, social, and civil opportunities. Ridehailing services are touted to improve mobility options, but there is scant research that incorporates this mode within an accessibility framework. This paper employs a generalized cost measure in a multi-modal accessibility framework, namely Access Profile Analysis, to assess the role of ridehailing in providing job access to historically under-resourced parts of Toronto, Canada, referred to by the city as Neighborhood Improvement Areas (NIAs). Ridehailing is analyzed both as a mode of commute and as a feeder to the transit network (a first-mile solution). The results indicate that there are two main determinants of the extent to which ridehailing provides additional accessibility over transit: the transit level of service at the origin zone and the zone's proximity to employment opportunities. The ridehailing mode is shown to increase accessibility especially to closer destinations (jobs), with the highest improvement seen in the city's inner suburbs. On the other hand, integrating ridehailing with public transit does little to improve access to jobs. Compared to the rest of the city, NIAs experience a higher accessibility improvement from ridehailing alone, but not from its integration with transit. Nonetheless, job accessibility remains lower in NIAs than in other areas – even after the introduction of ridehailing.     

Public transport accessibility in metropolitan areas: A new approach incorporating population density

Improving public transport accessibility can be considered an effective way of reducing the external costs and negative side effects of motorized commuting. Although there have been many studies conducted that have measured access levels to public transport stops/stations, there has been limited research on measuring accessibility that integrates population density within geographical areas. This study develops a new measure that considers public transport service frequency and population density as an important distributional indicator. A public transport accessibility index (PTAI) is formulated for quantifying accessibility within local areas in metropolitan Melbourne, Australia. A public transport network model is applied to identify the service coverage of public transport modes using a Geographical Information System (GIS). A consistent method is introduced for evaluating public transport accessibility for different levels of analysis, from single elements, including public mode stops to network analysis. The Victorian Integrated Survey of Travel and Activity (VISTA) is used to evaluate the index and examine the association between commuting trips undertaken by public transport and the level of accessibility within the Melbourne metropolitan region. Furthermore, the new index is compared with two existing approaches using the VISTA dataset. Key findings indicate that the PTAI had a stronger association whilst showing more use of public transport in areas with higher values of the PTAI.     

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.     

Catchment if you can: The effect of station entrance and exit locations on accessibility

The success of passenger railway systems depends on their ridership and thus the population they serve. A mechanism to increase ridership is to expose the existing system to more people by reconfiguring the station itself, for instance by adding extra entrance and exit gates to shorten the walking distance from a trip's origin or its final destination. Gates are key nodes giving pedestrians access from street network to boarding/alighting facilities and vice versa. Stations and platforms are places not points, passengers may spend up to 6 min a trip walking between platforms and the end of the station nearest their origin or destination. This study systematically evaluates the accessibility of train stations and the effect of constructing an additional ‘far-side’ gate at stations with a single ‘near-side’ entrance. A three-step approach is defined to generate an isochrone as the catchment area for any transport node. Results indicate that stations with a single gate along their platforms (usually on one end of them) have the potential to increase the accessibility to jobs and population by around 10% on average. Due to the walking network and land use characteristics, some stations will benefit more significantly by retrofitting a new gate. Also, four linear regression models are developed to illustrate the effect of expanded accessibility on the number of entries and exits at each station for two peak periods. Then, stations are ranked based on their added ridership, which can help authorities to prioritize the development and allocating resources.     

Accessibility and the journey to work through the lens of equity

Inequality in transport provision is an area of growing concern among transport professionals, as it results in low-income individuals travelling at lower speeds while covering smaller distances. Accessibility, the ease of reaching destinations, may hold the key in correcting these inequalities through providing a means to evaluate land use and transport interventions. This article examines the relationship between accessibility and commute duration for low-income individuals compared to the higher-income, in three major Canadian metropolitan regions, Toronto, Montreal, and Vancouver using separate multilevel mixed effects statistical models for car and public transport commuters. Accessibility measures are generated for jobs and workers both at the origin (home) and the destination (place of work) to account for the impact of competing labor and firms. Our models show that the impacts of accessibility on commute duration are present and in many cases stronger for low-income individuals than for higher income groups. The results suggest that low-income individuals have more to gain (in terms of reduced commute time) from increased accessibility to low-income jobs at the origin and to workers at the destination. Similarly, they also have more to lose from increased accessibility to low-income workers at the origin and to low-income jobs at the destination, which are proxies for increased competition. Policies targeting improvements in accessibility to jobs, especially low-income ones, by car and public transport while managing the presence of competition can serve to bridge the inequality gap that exists in commuting behavior.     

Equity in job accessibility and environmental quality in a segmented housing market: The case of Greater London

Job accessibility and environmental quality are rarely equally distributed in spatial and/or social dimensions within metropolitan regions. Availability of these affects the quality of residential locations, and can be expected to be capitalised into house prices. For prospective house owners, their options will be limited to sub housing markets within certain price bands depending on their available housing budgets. Availability and marginal prices of job accessibility and environmental quality, as well as trade-offs between them, might be different between these submarkets. Using Greater London as the case metropolitan region, this study explored such differences, to shed light on the role of housing market in equity and/or inequity in job accessibility, environmental quality and their interactions. Results of this study show that lower-price submarkets have advantages in job accessibility in terms of marginal price, but are disadvantaged in terms of availability. Differences are more mixed in marginal price and availability between the submarkets for environmental quality. When balancing job accessibility and environmental quality within constrained housing budgets, households in lower-price submarkets would find it relatively easier to gain job accessibility with less sacrifice on environmental quality as compared to those searching in higher-price submarkets, but hard to reach the higher levels of job accessibility that are mainly reserved for the higher-price submarkets.     

Modeling job accessibility using online map data: An extended two-step floating catchment area method with multiple travel modes

Current quantitative measures of job accessibility rarely consider the interaction between job opportunities and labor force, and the effects of dynamic travel mode choice. Drawing upon multiple open-source datasets, we develop a job accessibility index by extending the two-step floating catchment area method (2SFCA). The job accessibility indices are calculated for different commuting scenarios concerning distance, time, and travel modes. The results suggest that job accessibility is very sensitive to travel modes, and using a single travel mode would contribute to a biased job accessibility index. The job accessibility indices with combined travel modes are more geographically balanced than using a single travel mode. Furthermore, the new index is employed to examine the spatial pattern of job accessibility and explore the relationship between job accessibility, housing, and population in the Pudong district, Shanghai. The new job accessibility indices manifest the impacts of ring roads on the spatial distribution of job accessibility. A comparative analysis shows that the floating population has poor driving-based job accessibility but can access job opportunities using public transit. Also, poor job accessibility leads to low rent prices but has little impact on medium-high rent. Both transit-based and drive-based job accessibility indices are positively related to housing prices. Our study highlights the importance of considering dynamic travel mode choice in job accessibility research. The research outcomes also contribute to the literature on spatial mismatch by revealing the unique relationship between job accessibility, housing, and population in urban China.     

Is traffic congestion overrated? Examining the highly variable effects of congestion on travel and accessibility

Congestion is universally unpopular, but is it always a problem? Are some places more “congestion-adapted” than others? Using data for Los Angeles, we examine whether the geographies of congestion and accessibility are distinct by mapping and describing them across neighborhoods. We then estimate a series of regression models of trip-making to test the net effects of traffic delays on behavior. We find that there are places where people make many trips and engage in many activities despite lots of congestion, which tend to be more central, built-up areas that host many short trips; in other places, high congestion and low activity coincide. Why the variance? While congestion can constrain mobility and reduce accessibility, traffic is also associated with agglomerations of activity and is thus a byproduct of proximity-based accessibility. Whether agglomeration and congestion have net positive or negative impacts on activity participation thus varies substantially over space. Controlling for factors such as income and working at home, we find that the effects of congestion on access depend on whether congestion-adaptive travel choices (such as walking and making shorter trips to nearby destinations) are viable. Because “congestion-adapted” places tend to host more trip-making, planners may be justified in creating more such places in order to increase accessibility, even if doing so makes absolute levels of congestion worse in the process.     

Road accessibility and articulation of metropolitan spatial structures: the case of Madrid (Spain)

In the last few decades, rapid growth in mobility has facilitated the inclusion of distant places in metropolitan processes and the modification of traditional metropolitan areas into Polycentric Urban Regions. This paper aims to understand the articulation of metropolitan urban regions through a diachronic road network accessibility analysis with a focus on the Madrid Metropolitan Region (Spain) over a period of general increase in accessibility. The findings reveal that the metropolitan core has been reinforced and that its influence area has expanded. However, the main contribution of this work is the proposal of a methodological approach to identify city-profiles among the sub-centres organising the emerging polycentric urban structures.     

Access to jobs and apartment rents

This study empirically explores the relationship between access to jobs and apartment rents. Specifically, the research examines the following three hypotheses: job accessibility positively influences apartment rents, the effect of job accessibility on apartment rents varies by transportation mode, and the effect of job accessibility on apartment rents varies by rent level. To examine these hypotheses, this study applies gravity-type job accessibility indexes based on a study sample of 7077 observations in the Taipei Metropolitan Area, Taiwan, from the year 2009. The sample data are analyzed using linear and quantile regressions. The empirical evidence confirms the positive effect of job accessibility on apartment rents, and its variability depending on the transportation mode and rental level. The effect of job accessibility on apartment rent is significantly positive in the median or lower-rent-level sub-markets, but insignificantly negative in higher-rent-level sub-markets. Job accessibility by motorcycle and public transit has a higher positive influence on rent than accessibility by car. These findings provide new knowledge on the role of access to jobs in explaining apartment rents, and reveal a fresh policy direction on rental subsidy programs for lower-income workers living in cities.     

Does high-speed rail accessibility influence residential property prices? Hedonic estimates from southern Taiwan

A new high-speed railway line (HSR) connects seven metropolitan areas in Taiwan. From Tainan, it is possible to reach Kaohsiung, Chiayi and Taichung in less than one hour, implying an enlarged spatial range of feasible commuting opportunities. The implicit price of HSR accessibility is estimated using hedonic price functions for the residential property market. The results of pre-specified and Box-Cox hedonic price functions are compared. The estimated functions show that HSR accessibility has at most a minor effect on house prices. High ticket prices and entrenched residential location patterns prevent otherwise feasible daily commuting opportunities between Tainan and other cities.     

Proximity changes to what and for whom? Investigating sustainable accessibility change in the Gothenburg city region 1990–2014

This paper operationalizes the concept of sustainable accessibility by emphasizing the environmental and social dimensions of sustainability from a spatial perspective. In doing so, we develop a heuristic model that focuses on the crucial dimensions of who gets access to what by using sustainable means of movement. We apply our conceptual approach in an examination of trends in sustainable accessibility for different social groups living in Gothenburg, Sweden between 1990 and 2014. On the basis of welfare-related and time-geographical considerations, we investigate accessibility by proximity for low- and high-income earners, people with small children, and elderly people. We investigate to what extent proximity to fundamental facilities increases or decreases over time, indicating changing conditions for sustainability. The results show that opportunities for living a local life and achieving accessibility via proximity differ socially. Low-income earners and the elderly generally live closer to the facilities important for daily life than do high-income earners and parents of young children. We also show that the opportunities for various social groups to obtain access by proximity change over time. For example, we observe a trend in which over time older people face reduced opportunities to reach daily facilities in their local neighborhoods.     

The impacts of congestion on automobile accessibility. What happens in large European cities?

Every day, a significant part of the population in large cities suffers transport congestion. One effect of this is a change in the spatial distribution of accessibility, which may lead to people or businesses finding themselves temporally in areas where accessibility values are lower than either desired or required. This paper studies changes in automobile accessibility over the course of the day, as caused by congestion of the road network in eight metropolitan areas of the European Union: London, Paris, Madrid, Berlin, Barcelona, Rome, Hamburg and Milan. The study was carried out using millions of data points on real speeds on segments of the road networks gathered over the course of two years from TomTom® devices, which provided for the incorporation of a dynamic perspective of accessibility. In each of the areas studied, the different impacts of congestion on automobile accessibility can be observed from differences in the distribution of opportunities and the provision of infrastructures, as well as from differences in culture and customs. Despite these differences, all cities experience two peaks with a lower value during the morning and afternoon. However, results show differences in the intensity and form of the effects of congestion on accessibility in these metropolitan areas. London, Paris and Rome are the cities where congestion has the greatest impact on automobile accessibility, while the Spanish cities are hardly affected by it.     

Exploring the impacts of land use by service coverage and station-level accessibility on rail transit ridership

In this study, we employ spatial regression analysis to empirically investigate the impacts of land use, rail service coverage, and rail station accessibility on rail transit ridership in the city of Seoul and the surrounding metropolitan region. Our analyses suggest that a rail transit service coverage boundary of 500 m provides the best fit for estimating rail transit ridership levels. With regard to land use, our results confirm that density is positively related to rail transit ridership within a 750 m radius of each station. In contrast, land use diversity is not associated with rail transit ridership. We also found that station-level accessibility is as important as land use for explaining rail transit ridership levels. Finally, we conclude that development density and station-level accessibility measures such as the number of station entrances or exits and the number of bus routes at the station are the most important and consistent factors for promoting rail transit ridership.     

Qualifying accessibility to education to investigate spatial equity

Most accessibility studies are usually related to the number of potential reachable opportunities, disregarding attributes related to quality. Schools are usually distributed in the city, but does the quality of the service in these schools provide spatial equity to access the educational system? This study investigates accessibility to education considering different modes of transport and the quality of schools. It calculates and compares potential accessibility and revealed mobility in a highly unequal context, focusing on elementary schools in São Paulo, the largest city in Latin America. The empirical research reveals disparities between public and private schools regarding the quality and transport mode, unfolding spatial inequity. We hope that these findings provide further insights into better planning our cities for young people to move, study and live.