Measuring spatial proportionality between service availability,accessibility and mobility: Empirical evidence using spatial equity approach in Iran

Spatial proportionality plays an important role in recognizing inequities, the quality of actions to reduce them, and halting complicated and unclear cycle of inequities and even reversing their increasing trend. The aim of this study is to measure spatial equity based on spatial proportionalities (SESP), taking into account three-fold factors including service availability, accessibility and mobility. The SESP identifies proportionality between the quality of service distribution and allocating opportunities and the quality of getting access to locations and people's selections according to status quo. Thus, it examines the balance between supply and demand, optimization of distance and the number of choices people make out of total services and the role of move ability to use in compensating for shortages either in terms of service capacity or the level of human deprivation and reduction of effects of distance from services and etc. Gorgan as an old and intermediate city in northern Iran was selected as the case study. The results indicated that the study area does not enjoy suitable proportionality, revealing that the central and northern districts have much more enjoyment than the southern, eastern and western districts. Thus, there is disproportionality between supply and demand, high difference in provided choices and disproportionality between less enjoyed areas and their move ability to use services and inability to create walking travel pattern in Gorgan. Understanding of spatial proportionality can help the planners and policy makers to change their passive role into active in order to reduce inequities, adding to their knowledge on the underlying factors of inequity as well as the factors that hinder and reverse the cycle of inequity.     

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.     

Transit-based job accessibility and urban spatial structure

Job accessibility is a measure of people, opportunities, and transportation system that are fundamental elements of urban spatial structure. Therefore, job accessibility can be used as a tool to understand urban spatial structure. Studying transit-based job accessibility can provide more insight into inner cities. To study transit-based job accessibility, a person-based approach is needed in order to take full consideration of the elements. However, person-based approaches are substantially restricted by the availability of individual trip data. This paper takes a simulation approach to study transit-based job accessibility. First, transit-dependent worker agents are generated using a population synthesis. Then the agents are enabled with job search and commuting capabilities. Once the agents are deployed in a commuting simulation, individual commuting trips are recorded. An individual job accessibility index is developed based on simulated commuting trips. The index is normalized with an expected value of 1.0 and a measurable uncertainty level, which makes it easy to interpret and suitable for cross-regional studies. A case study is conducted in Tucson, Arizona, where about 10,000 transit-dependent worker agents produce more than 600,000 individual commuting trips during morning and afternoon peak hours. Census block, group-level job accessibility shows a random spatial pattern that coincides with a dispersed urban spatial structure of the case study area.     

Measuring accessibility to health care services for older bus passengers: A finer spatial resolution

Health care accessibility is a vital indicator for evaluating areas where there are medical shortages. However, due to the lack of population data with a satisfactory spatial resolution, efforts to accurately measure health care accessibility among older individuals have been hampered to some extent. To address this issue, we attempt to measure accessibility to health care services for older bus passengers in Nanjing, China, using a finer spatial resolution. More specifically, based on one month's worth of bus smart card data, a framework for identifying the home stations (i.e., a passenger's preferred station near their residence) of older passengers is developed to measure the aggregate demand at the bus stop scale. On this basis, a measurement that integrates the Gaussian two-step floating catchment area (2SFCA) and the adjusted 2SFCA methods (referred to as the adjusted Gaussian 2SFCA method) is proposed to measure accessibility to health care services for older people. The results show that: (1) almost all home stations experience inflated demand, especially those located in the suburbs; (2) despite abundant health care resources, home stations in urban districts are rarely identified as high accessibility stations, due to high demand densities among the older population; and (3) more attention should be paid to two types of home stations – those with a medical institution and those with bed shortages, respectively. The first type is predominantly distributed in the periphery of the city, in the suburbs where the travel time required to access the nearest health care service by bus is longer. The second type is mostly located in the outskirts of urban districts and in the central area of one suburb. These findings could help policy makers to implement more appropriate measures to design and reallocate health care resources.     

Measuring access to urban centres in rural Northeast Brazil: A spatial accessibility poverty index

This study proposes two innovative methods to measure transport-related exclusion in rural areas caused by the lack of access to basic opportunities (e.g. healthcare, education, jobs, etc). The Spatial Accessibility Poverty (SAP) indices, that are developed, are tailored for rural areas of the Global South and particularly illustrated in a case study in Northeast Brazil, where spatial data is most scarce. Gravity-based models are proposed based on travel impedance methods derived from i) Friction surface datasets, and ii) Kernel density maps. The spatial information is then aggregated at a municipality level creating indices that conjugate factors of severity and extent of SAP. The findings show that factors like deprivation of housing facilities (electricity and sanitation) and low population density are associated with critical SAP levels. The results also point out to higher prevalence of SAP in inner areas than the coastal areas of Northeast Brazil. The sensitivity analysis shows how data-poor contexts present a particularly complex environment to develop robust SAP measures. The findings emphasise the importance of considering sensitivity analysis and complementary factor analysis when applying SAP indicators for planning transport and for action prioritisation purposes. Since access to services and opportunities has been claimed to be a key difference between those who have escaped chronic poverty those still trapped in it, SAP indicators tailored to areas where poverty is most spread are of primary importance to promote a new standard of transport development strongly committed to eradicating poverty.     

Evaluating spatial accessibility to healthcare services under travel time uncertainty: A reliability-based floating catchment area approach

Most existing healthcare accessibility studies ignore the travel time uncertainty that are commonly encountered in road networks. This study aims to examine the impacts of travel time uncertainty on healthcare accessibility. A reliability-based two-step floating catchment area (2SFCA) method is proposed to evaluate healthcare accessibility under travel time uncertainty. The proposed measure generalizes the conventional 2SFCA measure by explicitly considering individuals' reliability constraints when scheduling visits to healthcare facilities in the face of travel time uncertainty. The proposed measure is further used to investigate travel time uncertainty impacts in a comprehensive case study. A big dataset of taxi trajectories is collected in the case study to extract dynamic information on travel time distributions. The results of the case study highlight the significant but heterogeneous impacts of travel time uncertainty on healthcare accessibility for various parts of the city at different times of the day. They also have several methodological implications for the evaluation of healthcare accessibility under travel time uncertainty.     

Measuring accessibility to grocery stores using radiation model and survival analysis

Measuring spatial accessibility to grocery stores and identifying food deserts have been of interest to planners and policy makers. However, measuring and quantifying accessibility in a way that relates to actual travel behaviors and preferences are challenging. This study aims to promote an existing radiation model by incorporating different transportation modes and time use diaries to provide a more realistic estimation of accessibility. We proposed a survival analysis method, such as the Cox proportional hazard model, as a novel approach to develop a cost decay function based on time use diaries. A multinomial logit model was applied to estimate the portion of people walking, traveling by car, and traveling by bus. A case study of grocery stores in Travis County, Texas, is used to illustrate the approach. The results indicate that for walking accessibility to grocery stores, the majority of zip codes fall into the very low, low, and moderate accessibility classes. Moreover, in most western zip codes transit accessibility to grocery stores is found to be very low. However, the spatial accessibility for some of such zip codes has been enhanced because of the presence of cars.     

Relevance of airport accessibility and airport competition

Airport accessibility is an important criterion for airport competition. The relevance of airport accessibility and airport competition was studied in this paper based on the panel data collected from nine large airports in Jiangsu province, China from 2005 to 2014. The results showed that the cost of expense, time and fatigue for the arrival at the airport are proposed to quantify levels of fastness, economy and amenity for the passengers to arrive at airport. The airport accessibility is significantly affected by airport passenger traffic and airline frequency. The passenger traffic can be increased by 2% with 1% increase of airport accessibility based on the analysis results of the nine large airports in Jiangsu province.     

Public transit accessibility approach to understand the equity for public healthcare services: A case study of Greater Mumbai

Urban public health is one of the most critical yet neglected aspects of urban planning in developing countries such as India. Inequity in access to government healthcare facilities affects the overall urban population and can substantially negatively impact the vulnerable population, who mostly rely on government healthcare services. In this paper, the accessibility measure for healthcare services by public transport is developed using travel time and the number of transit stops (accounting for transit connectivity) for Greater Mumbai. We also identified socially vulnerable wards (administrative units) using a Social Vulnerability Index (SVI), developed based on 16 indicators using Principal Component Analysis (PCA). Developed regression models showed that the proposed accessibility measure explains the coverage and usage of healthcare services better than the traditional accessibility measure, which is based on only aggregate level travel time impedances. South Mumbai has relatively better accessibility for public hospitals and dispensaries, whereas, lower level of accessibility is observed in the eastern part for public healthcare services. Assessment for the spatial inequity based on the Gini index, bivariate Moran's I, and mean access value reveals a higher degree of spatial inequity for accessing government hospitals for the slum population. The study developed a decision framework to suggest effective policy measures, which can be prioritised based on SVI to reduce the disparity in the spatial distribution of accessibility to government healthcare systems for vulnerable groups. Our findings can aid transportation and urban planners, health researchers, and policymakers to improve accessibility in under-served areas and give special attention to the needs of the vulnerable population.     

Measuring the long-distance accessibility of Italian cities

Long-distance accessibility is a crucial element for economic development and for territorial cohesion. To be revealing, however, a measure of accessibility must not only consider the distance or travel time of a single mode, but should include the fares, the frequency and the interchanges of all available modes.The paper aims to address whether and where there is an accessibility problem between Italian regions, through a comprehensive measure of accessibility covering the entire Italian territory. The measure used in the paper is potential accessibility, with an exponential decay impedance function. Different from similar studies, this one gives a more in-depth definition of impedance parameters due to the availability of a transport model that includes the entire Italian long-distance supply (roads, coaches, long-distance rail services, air services, and ferries). The opportunities at destination are proxied by population, and private and public sector employees.The main outputs are detailed maps of accessibility that are significantly more realistic than using simple infrastructure indicators or single-mode measures. In addition, some policy conclusions are drawn in terms of past and future investment policies.     

The impacts of high-speed rail extensions on accessibility and spatial equity changes in South Korea from 2004 to 2018

The construction of South Korean High-Speed Rail (HSR) or Korea Train eXpress (KTX) has been evolving in phases since its first operation in 2004. This development raises concerns whether the benefits from the extended HSR network would again be limited to the initial HSR corridors and will deepen the inequalities in accessibility with the rising issue of uneven regional development of the country. This paper measures the accessibility of each stage of HSR network extension and evaluates its spatial distribution, variation, and changes using weighted averaged travel time and potential accessibility indicators. The results of this study find different accessibility impacts from each stage of HSR extension. Although travel-time reduction and increased attractions have been widened in more cities by each HSR extension, the spatial equity is degenerated by the extension in 2010/2011 as the improvement of accessibility has been concentrated in cities along the primary HSR corridor near the already-advantageous Seoul capital area. In contrast, the future HSR extension in 2018 will enhance equitable accessibility to the isolated regions such as the northeast and the southwest regions of the country. However, the relative degree of accessibility improvement will not be large enough for increasing the spatial equity of accessibility without more extended HSR networks between provinces.     

Spatial accessibility and equity analysis of Amazon parcel lockers facilities

The onset of the COVID-19 pandemic has accelerated the growth of e-commerce and home deliveries. Automated parcel lockers are a way to improve delivery efficiency, but despite their rapid growth, little is known about their accessibility and equity impacts. Among e-commerce players in the U.S., Amazon stands out by its large market share. This research studies the location of Amazon lockers in Portland, Oregon utilizing highway, land use, employment, and sociodemographic datasets. Geographical tools and cluster analysis are utilized to estimate accessibility and equity metrics. Lockers tend to be located in mixed-use areas and can be utilized by a large percentage of the population. However, the equity metrics indicate that the current distribution of lockers could be improved to reach traditionally underserved populations. Given the environmental and economic advantages of lockers, policymakers should encourage the expansion of this type of last mile solution to avoid market failures in areas that are currently underserved.     

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.     

Reducing the uncertainty induced by spatial aggregation in accessibility and spatial interaction applications

Analyses of spatial interaction are to some degree plagued by uncertainty regarding the impact of spatially dispersed interaction masses within zones on travel times. In this paper, interaction-weighted travel times are computed from a matrix between regularly distributed points at fine resolution, and used together with secondary data to improve estimates of interaction weighted travel time based on commonly applied methods. The paper proposes a method for computing intra-zonal, interaction weighted travel times that is considerably less sensitive to spatial aggregation than existing approaches, and demonstrates that population-weighted centroids are to be preferred over geographically-weighted centroids.     

Measuring traveler involvement in urban public transport services: The case of Kaohsiung

The city of Kaohsiung has been urgently reducing its rates of ownership and usage of privately owned motor vehicles. The most important strategy undertaken thus far has been to build mass rapid transit systems. This study aims to apply the Involvement Theory to construct an inventory to measure level of travelers’ involvement in public transport services. The results indicate that the number of low involvement travelers is the critical factor that determines whether the new public transport system can effectively operate. They also provide authorities with precise marketing strategies targeting different groups in order to allow the new public transport systems to sufficiently meet public needs.     

A behavioral model of accessibility based on the number of available opportunities

The paper proposes a new behavioral definition of accessibility as the expected number of opportunities “available” for a subject to perform an activity, where “available” means that the opportunity i) is perceived as a potential alternative to satisfy one's needs, and ii) it can be reached given the spatiotemporal constraints of the individual's schedule. A new class of accessibility models is derived in accordance with the above definition, exploiting the strengths of both utility-based and opportunity-based models, and explicitly incorporating spatiotemporal constraints which may limit the availability of perceived opportunities. The proposed model is formulated for both active and passive accessibility, does not suffer from reflexivity issues, supports both trip-based and activity-based formulations, and scales up from individual to spatially aggregated opportunities, taking into account effectively the different ways of perceiving opportunities. Moreover, the resulting accessibility measure has a straightforward interpretation, being expressed in physical units, and is comparable across different locations. Performances of the proposed model in reproducing the active accessibility to cinemas in the Naples metropolitan area (Italy) are compared to those of a traditional isochrone-based measure and a distance–decay model. For this aim, measurements of individuals' perceived cinemas were gathered through a survey, and adopted for the calibration of both the accessibility models. Calibration results show that the proposed model outperforms both the traditional isochrone-based measure and a distance–decay model calibrated against the same dataset, better reproducing both the quantity and spatial distribution of perceived opportunities.     

Measuring the quality of port hinterland accessibility: The Ligurian case

Traditionally, distance was considered the parameter that could better reflect the economic influence of a seaport on land. Containerisation and intermodality progressively eroded such a paradigm and currently distance became only one of the factors across the overall “equation”. In this respect, a fundamental role is played by the effectiveness of inland connections. The better the connection of a port to the various inland markets, the bigger the potential to enlarge its overall captive area. Furthermore, the higher the “frictions” (bottlenecks, delays, etc.) for reaching the hinterland, the lower the inland traffic flows.The major purpose of the paper is to measure container traffic diversion from Ligurian ports (Genoa, La Spezia and Savona) to the main Italian and European competitors.The application of a gravity model will reveal the current role of distance in drawing hinterland market share among the selected ports. Moreover, for evaluating the unexploited potentialities of Ligurian ports, we compared real traffic flows with the outcomes of a spatial interaction model, reassigning inland container flows to the different sampled ports. The calculation of the traffic delta through a gap analysis, allowed measuring the “frictions” thwarting the connectivity between the Ligurian ports and the sampled hinterland regions. Finally, the paper discusses the nature and the reasons for the above traffic diversion.     

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.     

Evaluation of the spatial pattern of logistics facilities using urban logistics land-use and traffic simulator

Despite the growing research interests on the spatial restructuring of logistics facilities that occurred in many cities around the world, the relationship between the spatial pattern of logistics land use and the level of externalities is far from being elucidated. We use the Urban Logistics Land-use and Traffic Simulator (ULLTRA-SIM), developed for the Tokyo Metropolitan Area, to evaluate the level of externalities that accompany different spatial distribution patterns of logistics facilities. The ULLTRA-SIM takes a novel approach to analyze the urban freight impacts through the simulations of logistics facility locations, urban logistics chains, and truck flow. The results indicate that, while the moderate concentration and deconcentration of logistics facilities do not significantly affect the level of externalities, scarcity of logistics facilities in or near the high demand locations exacerbates negative externalities. Also, the results of the simulations underscore the need for rigorous analysis in order to reduce negative externalities through logistics land use policies.     

Measuring the structural determinants of urban travel demand

To be best prepared for tomorrow's cities we need to forecast urban travel demand. To this end, this study calibrates an urban travel demand model, which uses the principal structural variables that have been identified in the literature. It uses a robust econometric method, which has been little applied in the sphere of transportation. The results show that two variables stand out from the others: the user cost of transport – by private car and public transport – and urban density. It is surprising, but explicable with the available data, that the demand functions estimated for a given country are independent from the group of countries to which it belongs.