Examining circuity of urban transit networks from an equity perspective

Circuity of transit networks, defined as the ratio of network to Euclidean distance traveled from origin to destination stop, has been known to influence travel behavior. In addition to the longer time spent in travel, for networks where fare is based on distance traveled, higher circuity also means higher fare for the same Euclidean distance. This makes circuity relevant from an equity perspective. Using a case study of the urban transit network of Amsterdam in the Netherlands, this study explores the role of transit circuity on the disparity in distance traveled by travelers' income profile and its implications on travel times and costs for networks with distance-based fares. The analysis is based on travel patterns from smart card data for bus, tram, and metro modes, combined with neighborhood level income data. Results reveal that in Amsterdam, the higher the share of high income people living in proximity to a transit stop, the lower the circuity of journeys from the stop, when controlled for the Euclidean distance covered and spatial auto-correlation. The uneven distribution of circuity exacerbates the disparity in distance traveled, and hence fare paid between the income groups. However, the travel time per Euclidean distance favors the low income group, possibly due to the circuitous routes serving these areas being compensated by higher travel speeds. This study highlights the role of transit network design in determining its equity outcomes and emphasizes the importance of considering equity during route and fare planning. The process followed can be adapted to examine equity for other urban networks.     

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.     

Immigrant settlement patterns,transit accessibility,and transit use

Public transit is immensely important among recent immigrants for enabling daily travel and activity participation. The objectives of this study are to examine whether immigrants settle in areas of high or low transit accessibility and how this affects transit mode share. This is analyzed via a novel comparison of two gateway cities: Sydney, Australia and Toronto, Canada. We find that in both cities, recent immigrants have greater levels of public transit accessibility to jobs, on average, than the overall population, but the geography of immigrant settlement is more suburbanized and less clustered around commuter rail in Toronto than in Sydney. Using logistic regression models with spatial filters, we find significant positive relationships between immigrant settlement patterns and transit mode share for commuting trips, after controlling for transit accessibility and other socio-economic factors, indicating an increased reliance on public transit by recent immigrants. Importantly, via a sensitivity analysis, we find that these effects are greatest in peripheral suburbs and rural areas, indicating that recent immigrants in these areas have more risks of transport-related social exclusion due to reliance on insufficient transit service.     

The ecological implications of visitor transportation in parks and protected areas: Examples from research in US National Parks

The demand for recreation and nature-based tourism experiences in parks and protected areas continues to grow in many locations worldwide and in response, many parks are employing transit services designed to improve visitor access. Transit services (e.g., public bus service) are a component of the overall park transportation system and are very desirable in park settings as they yield many advantages over personal auto access including reduced congestion in parking areas, a reduced carbon footprint, and an enhanced visitor experience. However, a growing body of research also suggests that the delivery of visitors via transit to destinations within a park or protected area may have unique ecological disturbance implications resulting from increased visitor use, density, and altered spatial and temporal use patterns. In this paper, we examine the relevant literature and present examples from recent research that illustrates the potential range of ecologic impacts from visitor deliveries via park transportation systems. We conclude while transit systems remain very desirable in park settings, depending on a range of situational factors, conventional, demand-driven planning and management approaches may result in unintended impacts to ecological conditions. Overall, this discussion provides a framework for improved management of the potential ecological impacts of protected area transportation systems.     

Daily fluctuations in transit and job availability: A comparative assessment of time-sensitive accessibility measures

Accessibility to jobs by transit is increasingly incorporated into transportation and land-use planning objectives, as it is proven to be a relevant indicator for assessing land-use and transport performance. With a rise in time-sensitive accessibility measures, choosing the appropriate measure is increasingly challenging for engineers, planners and policy-makers. This research presents a comparative analysis of three accessibility measures, two of which are time-sensitive. Relative accessibility measures are generated for five time periods based on a) constant transit service and number of jobs (constant); b) variable transit service and constant number of jobs (static) and c) variable transit service and variable number of jobs available (dynamic). The measures are first assessed by incorporating them into a transit mode share model. Interestingly, findings show that all three measures behaved similarly in the three regression models. Furthermore, all accessibility measures are found to be highly correlated. The study suggests that the most commonly used accessibility measure (constant measure at 8 am) is representative of the relative accessibility (static or dynamic) over the course of the day and is thus appropriate and meaningful to be used by policy-makers, engineers and planners.     

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 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.     

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.     

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.     

Walk-to-transit demand estimation methods applied at the parcel level to improve pedestrian infrastructure investment

Public transportation is a critical component of cities' transportation system that can be supported by a safe, complete, and connected pedestrian infrastructure. Agencies spend millions of dollars each year to improve transit ridership, yet many of the transit destinations do not have adequate pedestrian infrastructure to connect to the transit stops creating a substantial barrier to growing demand. This is particularly true in suburban areas. This paper presents a replicable methodology for estimating relative parcel-level transit demand such that analysts can conduct fine-grained evaluation and prioritization of the pedestrian network enhancements as they relate to public transit system. To this end, pedestrian infrastructure can boost transit ridership and enhance riders' safety. We rely on spatial data available in most cities coupled with land use and socioeconomic data to generate potential relative number of walk-to-transit trips for each parcel and weight the occupied road segments based on the results from mode choice and gravity models. Using this GIS-based tool, we identify road segments that have a higher potential in serving as a walking path to transit stops and prioritize gaps in existing sidewalk infrastructure. This result eliminates arbitrary sidewalk investment scoring programs and the reliance on transit walksheds to direct investment. We apply this method to a case study of the city of Knoxville and discuss the challenges and possible solutions. This approach can help city planners and engineers in data-oriented investment strategic management of sidewalk enhancement programs that support transit.     

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.     

Airport location in multiple airport regions (MARs): The role of land and airside accessibility

This paper approaches the airport location problem as a function of accessibility considerations. First, a structural equation model is established to find the relationship between the size of an airport catchment area and its flight network scale. Landside and airside accessibilities are measured by the qualities and costs of surface transportation and flight networks. The two accessibilities are combined to form a regional air transportation accessibility profile, which can be used as a criterion to evaluate airport locations at a macro-planning level. Finally, the scenarios of airport locations in terms of small and large areas are analyzed using two regional case studies in China.     

Impacts of high-speed rail on the inequality of intercity accessibility: A case study of Liaoning Province,China

The rapid development of Chinese high-speed rail (HSR) not only improves the convenience of daily transportation, but also promotes the regional economy of cities along the HSR lines. Accessibility improvement and spatial inequality reduction caused by HSR would play a positive role in transportation development projects appraisal and help achieve the regional coordinated development. Our purpose is to assess how much improvement of economic potential accessibility can each city get from the HSR based on the existing highway and HSR networks, as well as the changes in spatial disparity and accessibility distribution patterns. Taking Liaoning Province as a case, this paper studies the spatial pattern and inequality of accessibility in two intercity transportation scenarios using a gravity-based model. The sensitivity analysis of the parameter and the test of different mass indicators are also conducted. The results show that cities in the central areas have better accessibility than peripheral areas. Cities in the peripheral areas and near the HSR lines tend to benefit more from HSR. The inequality of accessibility decreases a lot in cities with HSR access but only has a minor reduction on a whole scale.     

Evaluating sustainability and land use integration of BRT stations via extended node place model,an application on BRT stations of Tehran

Modern transportation planners and urban designers are looking for a practical solution toward sustainable, accessible, and cost-effective development of public transportation. Achieving a well-balanced transit-oriented development (TOD) requires a clear illustration of the existing public transportation, land use, and correlations between them. Bus rapid transit (BRT) is a well-known strategy toward developing high-quality transit networks and would be a reasonable transportation choice if allied with a suitable walkable design in surrounding areas. In this paper, the node-place model is developed and applied on BRT stations in Tehran to be analyzed and clustered using three extended TOD indicators. The design index, representing the accessibility and walking potential, is further improved by measuring spatial specifications and walkway density parameters. Furthermore, the place index, representing demand and land use specifications of the area, is investigated through the calculation of possible destination points (PDPs) in the vicinity of stations. The model is reapplied after correlation analyses on input data to find stations' behavior by using more effective parameters. The results indicate that appropriate access to the stations requires a tight network of walkways that offers multiple routes to the stations. Meanwhile, a dense and sophisticated pedestrian area needs to offer short routes with minimum turns required to reach the station. Moreover, in each station, some factors are found to be more dominating. Changes in these factors have more profound effects than other factors. This paper aims to identify these factors and help planners develop TOD areas sustainably.     

Measuring non-motorized accessibility: issues,alternatives, and execution

While the transportation planning literature contains many examples of the calculation of measures of accessibility for urban areas, these measures are largely restricted to motorized modes and to a handful of destination activities. This paper explores the issues related to the development of accessibility measures for non-motorized modes, namely bicycling and walking. We note that difficulties in calculating accessibility measures arise primarily from problems with data quality, the zonal structure of transportation planning models, and the adequacy of models and travel networks for describing and predicting travel by non-motorized modes. We present practical strategies for addressing these issues. The application of these methods is illustrated with the calculation of accessibility measures for a small study area in Minneapolis, MN (USA). The paper concludes with some direction for future development of non-motorized accessibility measures and ideas about their applicability to the practice of transportation planning.     

Streetcar projects as spatial planning: A shift in transport planning in the United States

Currently dozens of U.S. cities are in the midst of planning and building modern streetcar systems. Though seemingly mobility investments, the intended impacts of these streetcar projects reach beyond transportation and represent a strong turn toward strategic spatial planning through transportation infrastructure. Proponents of modern streetcars argue that they are tools of placemaking as much as if not more than improvements for transit services. Unlike transit investments of a century ago, when privately operated streetcars were a decentralizing force that helped disperse overcrowded central city cores and open new land for real estate development, current streetcar projects in the United States are expected to concentrate activity and economic development in select corridors. The majority of these new systems rely on transit technologies that are significantly improved over the carriages of old, with modern features, smooth rides and quiet operations. Yet for all the improvements to the vehicles and services, new streetcar investments no longer primarily improve transit accessibility. Rather, modern streetcars are part of strategic amenity packages cities use to achieve real estate and economic development goals. This use of transportation infrastructure as an amenity for a particular location is a shift away from traditional transportation planning processes, and the expected benefits, in particular, stand apart as being deliberately spatial. We use planning documents and data from ballot box initiatives to evaluate expected transportation benefits relative to indirect benefits through economic development. We find that approximately three-quarters of all expected benefits from streetcar projects accrue to property development with the remaining expected benefits assigned to transportation. However, we do not find sufficient empirical evidence in the literature to support such certain claims of positive effects on property values and the built environment. We argue that the increasing tendency of cities to leverage streetcar projects for non-transportation purposes represents a turn to the use of infrastructure as a tool of spatial planning.     

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.     

Beyond sharing: cultivating cooperative transportation systems through geographic information science

Transportation systems are facing unprecedented challenges in the 21st century. Increasing the efficiency of transportation systems alone will not solve these problems and may exacerbate them. Instead, we must extract new transportation capabilities related to more cooperative decision-making across a wide range of time horizons, spatial scales and decision contexts. This paper discusses the role of sensed transportation, geographic information science and social media to cultivate transportation systems where participants share, cooperate and act collectively to solve operational, tactical and strategic mobility and accessibility problems. This paper also provides a vision of the future by imaging a seamless multimodal transportation system combined with a virtual environment where data streams are fused, interpreted and made available with tools for human engagement and shared decision making. This paper concludes by outlining a GIScience-centric research agenda.     

Suburbanization and transit-oriented development in China

The suburbanization of large Chinese cities has placed many residents in locations that are far less accessible than their prior residences, requiring motorized travel. This paper examines the impacts of relocation to outlying areas on job accessibility, commuting mode choice, and commuting durations based on a current-day and retrospective survey of recent movers to three suburban neighborhoods in Shanghai. Job accessibility levels were found to decline dramatically following the move, matched by increased motorized travel and longer commute durations. Relocating to a suburban area near a metrorail station, however, was found to moderate losses in job accessibility and for many, encourage switches from non-motorized to transit commuting. We conclude that transit-oriented development holds considerable promise for placing rapidly suburbanizing Chinese cities on a more sustainable pathway.