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.     

What is ‘neighborhood walkability’? How the built environment differently correlates with walking for different purposes and with walking on weekdays and weekends

Residential environments are associated with people's walking behavior. Transit-related, non-transit-related, and recreational walking may be differently associated with residential environments on weekdays and weekends, but empirical evidence is scarce. We therefore examined 1) to which extent these types of walking correlated with natural and built environmental characteristics of residential neighborhoods, 2) how these correlations differ for walking on weekdays and weekends, and 3) what substitution and complementarity effects between different types of walking exist. Our sample comprised 92,298 people aged ≥18 years from the pooled Dutch National Travel Survey 2010–2014. Multivariate Tobit regression models were used to assess the associations between the natural and built environment and the three types of walking (in average minutes per day). Our models accounted for cross-correlations between the walking types. Our results showed that denser residential areas encouraged both longer transit-related and non-transit-related transport walking on weekdays and weekends, whereas lower density neighborhoods were positively associated with recreational walking on weekdays. Shorter distances to public transport were only significantly associated with transit-related transport walking on weekdays. Shorter distances to daily facilities were positively associated with non-transit-related transport on weekdays. No significant associations between built environment and recreational walking were found on weekends. Additionally, some compensation effects between different types of walking seem to be at play: during weekends, recreational walking was inversely correlated with transit-related transport walking. Residential environments seem to affect walking types in a different way, suggesting that one size fits all policies might be less effective. Intervention strategies should be tailored for each walking type separately.     

A two-stage residential location and transport mode choice model with exposure to traffic-induced air pollution

Air pollution is an increasing concern to urban residents. In response, residents are beginning to adapt their travel behaviour and to consider local air quality when choosing a home. We study implications of such behaviour for the morphology of cities and population exposure to traffic-induced air pollution. To do so, we propose a spatially explicit and integrated residential location and transport mode choice model for a city with traffic-induced air pollution. Intra-urban spatial patterns of population densities, transport mode choices, and resulting population exposure are analysed for urban settings of varying levels of health concern and air pollution information available to residents. Numerical analysis of the feedback between residential location choice and transport mode choice, and between residents' choices and the subsequent potential impact on their own health suggests that increased availability of information on spatially variable traffic-induced health concerns shifts population towards suburban areas with availability of public transport. Thus, health benefits result from reduced population densities close to urban centres in this context. To mitigate population exposure, our work highlights the need for spatially explicit information on peoples' air pollution concerns and, on this basis, spatially differentiated integrated land use and transport measures.     

Walking,cycling, and public transport for commuting and non-commuting travels across 5 European urban regions: Modal choice correlates and motivations

The objective of this study was to explore individual and contextual-level characteristics associated with active (walking and cycling) and public transport as main travel modes for both non-commuting and commuting purposes, in residents of five European urban regions. We also described participant-reported motivations for modal choice for each journey purpose. The study used multilevel models to investigate cross-sectional associations of individual (i.e. age, gender, educational level) and contextual (defined by a combination of residential neighbourhood characteristics in typologies) characteristics with the choice of active and public transport as outcome. Based on an online survey of 6037 residents of Ghent and suburbs (Belgium), Paris and inner suburbs (France), Budapest and suburbs (Hungary), the Randstad (including the cities of Amsterdam, Rotterdam, The Hague and Utrecht in the Netherlands) and Greater London (United Kingdom), we observed associations with both individual and contextual characteristics.Results of the multilevel modelling show that the probability of using active or public transport as main mode varies depending on both individual and contextual characteristics. At individual level, relations with gender, age, education, weight status and having at least one child varied according to main transport mode and/or purpose. For example, overweight participants reported lower level of cycling for commuting and non-commuting travels than normal-weight participants. In the context of non-commuting travels, participants with one or more child reported less public transport use and more walking (vs participants without children). Among contextual-level variables, urban characteristics of the residential neighbourhood defined by four clusters (according to food environment, recreational facilities and active mobility opportunities) were associated with public transport and walking but not with cycling. For active transport the most important reasons were “I like to travel (on foot or by bike)” and “I want to be physically active” for both travel purposes. “Public transport facilities nearby” was indicated as the most important reason for public transport (for both trip purposes) – the second was “Journey time”.Our findings highlight the importance of exploring a combination of multiple correlates at individual and contextual level according to journey purposes and suggest that the role of health-related individual characteristics such as weight status need further exploration.     

Social exclusion, location and transport disadvantage amongst non-driving seniors in a Melbourne municipality, Australia

Over the past decade, researchers have refocused their attention upon the interconnection between locationally disadvantaged communities and poor transport services in order to better understand social exclusion. Limited access to private and public transport has often been identified as a major contributing factor to social isolation and economic poverty that certain groups in the community experience. To date, an insufficient amount of research attention has focused on the elderly or seniors, who are often identified as being subject to social exclusion because of difficulties associated with travelling outside their homes to access services and facilities especially for non-car drivers. Moreover, a disproportionate amount of research undertaken on transport related forms of social exclusion in Australia has understandably looked towards the outskirts of its major urban centres, where services and facilities are sparsely located and generally only accessible by car. This paper provides a different insight by analysing a middle distant municipality where large spatial concentrations of seniors are to be found, some of whom do not have ready access to a car or have difficulty accessing the public bus service. Using a variety of data sources for a municipality in Melbourne, this case study reveals that social exclusion of non-car driving seniors is reinforced by a regional public transport system that cannot adequately service the entire municipality. For now, the incidence of locational and transport related disadvantage is restricted to small pockets of the municipality, but as seniors age and surrender their car driving licences this problem could become more serious. The study concludes by calling for more analyses to be undertaken into transport engendered social exclusion if this problem is to be contained as the post-war baby-boomers generation ages across most of the middle suburbs of Australian cities.     

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.     

The factors in residents' mobility in rural towns of China: Car ownership,road infrastructure and public transport services

The improvement of rural people's mobility in developing countries has informed many policies. Still, debates remain on which policies are efficient, for instance, building more roads, providing public transport or promoting car ownership. The empirical evidence for these debates at the national level remains scarce. As a result, this paper aims to provide fresh evidence for discussions by examining residents' mobility in China using nationwide survey data with 12,524 respondents from 119 rural towns. The results of the analysis show car ownership is the most significant factor influencing rural people's mobility than other factors. Higher car ownership relates to a higher travel frequency to counties or cities. Other kinds of transport vehicles (i.e. electric cars, motorcycles and electric bikes) also have positive but relatively weaker impacts on rural mobility. For public transport, it is more accessible to access bus stops, which encourages travel to higher-order centres rather than increasing the frequency of county bus services. The accessibility of high-quality road systems tends to have a negative influence and has combined effects with levels of local services. People from towns with insufficient local services and poor access to highways travel the most frequently to higher-order centres. This study highlights the critical role of road investments and car ownership enhancement policies in improving mobility. Moreover, this study also underscores the supplemental role of public transport services given the current low car ownership rates in rural towns of China and the global consensus on sustainable green transport development. It highlights the importance of engaging eco-friendly and locally adaptive transport alternatives, such as electric cars and electric bikes. It also calls for a rational distribution of bus stops and more flexible, convenient, and physically accessible public transport and carshare modes in rural China.     

The influence of residential dissonance on physical activity and walking: evidence from the Montgomery County,MD, and Twin Cities,MN, areas

This study investigates to what extent a mismatch between residential preferences and actual residential locations is associated with residents’ physical activity and walking. The residents of Montgomery County, MD, and Twin Cities, MN, were classified into four residential subgroups, and their walking and physical activity outcomes were compared. The results showed that, for transport activity and walking outcomes, participants living in a urban location and preferring a urban environment were more likely to be active than those who lived in a suburban location and preferred a suburban environment. In a highly dense region, the influence of preferences might be overridden by the characteristics of neighborhood locations. With respect to recreation activity, no significant associations were found regarding neighborhood locations or preference for neighborhood environment.     

Powered-two-wheelers for city commuting: Insight from Australia's three largest capital cities

The journey to work receives a great deal of research attention due to the peak demand on the transport system. Cities are increasingly concerned with managing traffic congestion and reducing pollution and most of the focus of this research has been on cars, public transport, walking and cycling. In contrast, the role of powered two-wheelers (PTWs), including motorcycles and scooters, in commuting has received little attention, particularly in the context of cities in the developed world. This paper provides new insight into commuting by PTW by drawing on census journey to work data from Australia's three largest cities (Sydney, Melbourne and Brisbane) combined with an intercept survey of PTW commuters in Melbourne. It explores the extent of, and changes in, PTW commuting as well as the demographics of PTW commuters. While PTWs account for only a small percentage of urban commuting in Australian cities, their use is growing rapidly and there is a concentration of commuting by PTW into city centres. PTW commuters tend to be high-income males in skilled professional and technical professions. The implication of these findings for transport policy are discussed.     

Fair accessibility – Operationalizing the distributional effects of policy interventions

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

Accessibility measurements in São Paulo,Rio de Janeiro,Curitiba and Recife,Brazil

Increasing attention is given to public transport services in cities of the Global South as a tool to enhance social inclusion and support economic development. Against this background, developing and evaluating indicators that quantify the distribution of public transport services from a social equity perspective is essential. The aim of the study is, therefore, to assess the equity of public transport services in four metropolitan regions in Brazil (São Paulo, Rio de Janeiro, Curitiba and Recife) with two commonly used indicators of public transport provision. The first indicator measures proximity to rapid transit infrastructure (bus rapid transit, light rail and heavy rail stops with high frequency throughout the day), and the second measures accessibility to jobs by public transport. While simple indicators of proximity to public transport stops are most commonly used given their ease of operationalization and communication, accessibility to job indicators are more representative of the benefits provided to individuals by the public transport network. Combining these two indicators in one study provides a quantitative assessment of the socio-spatial distribution of public transport services in four large metropolitan areas in Brazil and the results demonstrate that lower-income households are disadvantaged in terms of public transport services in all four metropolitan areas. Furthermore, the results highlight the importance of quantifying accessibility by public transport, in addition to proximity to rapid transit, and thereby sheds light on the importance of developing openly available public transport schedules and geographic data. This study is of relevance to planners and researchers wishing to measure and evaluate public transport equity in the Global South.     

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 compact city for the wealthy? Employment accessibility inequalities between occupational classes in the London metropolitan region 2011

The prevalence of gentrification and housing marketisation processes in many cities points to increasingly wealthy inner-city areas and potentially greater population segregation by income. It is plausible that these trends are contributing to regional accessibility inequalities, though quantitative research testing this link is limited. This paper examines differences in employment accessibility between Standard Occupational Classification groups in the London Metropolitan Region for 2011 for car, transit, bus only and walking modes. Additionally, changes in occupational class populations 2006–2016 are considered, revealing continuing inner-city gentrification. Employment accessibility is calculated using cumulative measures, based on travel times from multi-modal network modelling. The results show that while car accessibility is relatively equal between occupational classes, public transport, bus and walk accessibility have significant inequalities favouring professional classes. Low income groups have lower accessibility for the most affordable bus and walk modes, and inequalities are greater for residents in the wider metropolitan region. Furthermore, professional groups combine accessibility advantages with the highest rates of owner occupation, maximising housing wealth benefits. Lower income groups are exposed to rent increases, though this is offset by social housing, which remains the most prevalent tenure in Inner London for low income classes.     

Neighborhood characteristics and transport walking: Exploring multiple pathways of influence using a structural equation modeling approach

In studies of neighborhood effects on transport walking, residential preferences along with other personal characteristics (walking attitude, factors that affect decision to walk for transport) are important factors to consider. However, few studies have examined relationships between neighborhood characteristics and transport walking accounting for a complex suite of personal factors. This study employed a structural equation modeling approach to examine associations between neighborhood characteristics and transport walking behaviors by accounting for residential preferences, self-assessed factors that affect decision to walk for transportation, and socio-demographics; and to examine whether neighborhood effects were modified by walking attitude and residential preferences. Based on a cross-sectional phone and mail survey of 2848 residents of New York City, Baltimore, Chicago, Los Angeles, St. Paul, and Winston Salem in 2011–12, we found neighborhood characteristics had significant independent associations with transport walking, even after adjusting for residential preferences and other personal factors. Neighborhood effects on transport walking did not differ significantly by walking attitude or residential preferences. Our findings highlight the importance of neighborhood effects in promoting transport walking, and suggest that while residential preferences are important factors, they do not obviate the neighborhood effects on transport walking.     

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.     

Residential dissonance and walking for transport

The concept of residential dissonance contextualizes the combined impact of built environment and individual travel and land-use preferences on travel behavior. A limited number of studies have explored the effect of residential dissonance specifically on walking. However, evidence from the active travel literature suggests that the environmental characteristics associated with diverse active travel modes differ to some extent. This study addresses residential dissonance in a framework specific for walking outcomes, as the applied neighborhood boundaries, residential preferences and the observed built environment were operationalized with measures related to walking for transport. SoftGIS, a public participatory GIS method allowing the mapping of frequently visited destinations was used to survey the daily walking behavior of 772 respondents aged 25–40 years living in the Helsinki metropolitan area, Finland. Ordinal logistic regression analyses were used to assess the adjusted odds of walking a high share of estimated monthly trips and travel distance. The identified residential dissonance groups were found to have significant associations with the walking outcomes. Associations between the observed neighborhood walkability and the walking outcomes varied by trip purpose, being more consistent with walking to utilitarian than to recreational destinations. Overall, the results support views on the interconnectedness of individual attitudes and the built environment in facilitating walking for transport.     

Linking expected mobility production to sustainable residential location planning: some evidence from Flanders

Based on a set of spatial proximity characteristics this paper develops a model that estimates for every neighbourhood in Flanders (Belgium) the amount of traffic that would be generated by an additional residential unit when socio-economic variables are held constant. The results show that residential density, land use diversity and proximity of facilities influence daily travelled distances when these variables are measured in the immediate vicinity of the residential location of the respondent (within a radius of 1 km). When aggregating these variables at a larger geographical scale, in most cases the impact proves no longer significant. Variables based on the spatial distribution of jobs, or on the global accessibility of the entire population in the study area, do not show any significant effects on the travel distance.Despite the statistical significance only a fraction of the observed variance in reported distances is explained by characteristics of spatial proximity. However, we can assume that the importance of spatial structure in the genesis of mobility patterns will increase in case the cost of transport would rise (cf. peak oil). For this reason, the application of the mapped results of the proposed model could contribute to the practice of sustainable spatial planning.     

Quantifying spatial gaps in public transport supply based on social needs

This paper concerns a research project to identify spatial gaps in public transport provision for people who are socially disadvantaged. The paper outlines the research context for measurement of public transport supply and needs, and then describes the methodology developed for an application in Melbourne, Australia. Results of the application are described including key findings on spatial gaps in services relative to social needs. The research identifies significant gaps between services supplied and social needs for transport services. Consistency of these findings with research in other Australian cities are noted. Implications for policy development are suggested.     

The spatial characteristics and influencing factors of modal accessibility gaps: A case study for Guangzhou,China

This paper presents an analysis of the spatial characteristic of the modal accessibility gap (MAG) in Guangzhou based on travel times for public transport and cars to public centers calculated by the Travel O-D point Intelligent Query System (TIQS). Four spatial regression models are used to investigate the effect on the MAG of six factors of the built environment (distance to city public centers, residential density, landuse mix, bus stop density, metro station density and road network density). The results show that travel time for a given origin to destination (OD) trip is likely to be larger by public transport than by car, especially for a trip of longer travel time. The MAG values of all the communities are larger than 0, indicating that when compared with public transport, travelling by car takes less travel time for individuals. Residential density, land-use mix, bus stop density and metro rail station density have significant negative direct impacts and indirect impacts (spatial spillover effects) on MAG, which indicates that appropriate increase in community residential density, providing diversified service facilities within a community, and improving public transport supply are beneficial to promote modal shift. Specifically, the role of metro rail is greater than that of buses. However, the road network density has significant direct positive impacts on MAG, and its spillover effect is also significantly positive, which indicates that building more roads is not an effective way to narrow the accessibility gap between public transport and cars but may facilitate more car travel instead.     

Determining intra-urban spatial accessibility disparities in multimodal public transport networks

Urban rail systems have been added to public transport systems, thereby changing distribution disparities in urban spatial accessibility. These disparities reflect both the ability of the public transport system to meet the needs of residents and the locational pros and cons of public service facilities. In this paper, integrated accessibility metrics are used to assess the disparities in Nanjing, Jiangsu Province, China. This is achieved by dividing the urban space into a multilevel grid that can be easily combined with grid-based population data to facilitate accessibility modeling, calculation, and evaluation. Additionally, an acquisition method for more accurate travel time data in the multimodal public transportation network was developed on the basis of an Internet mapping service. This provides a realistic, multimodal, door-to-door modeling approach that avoids the requirement of building complex traffic networks through Geographic Information System (GIS) software and simplifies road network modeling efforts. The results show that this modeling method can be used to reflect the accessibility disparities in the Nanjing urban space objectively and accurately.