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

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

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.     

Enhanced Huff model for estimating Park and Ride (PnR) catchment areas in Perth,WA

A train station catchment area delineates the spatial territory from which the users of a train station are drawn. The size and shape of this catchment can be influenced by a variety of factors, such as the transport network, the location of stations and the service quality they offer, as well as the land use density and diversity in the transport corridor. Although numerous studies have been conducted to understand the size of catchment areas, limited research has focused on determining the spatial boundary (shape) of train station catchments. This paper develops a framework for deriving a spatial boundary of a Park and Ride (PnR) catchment area by incorporating the Huff model and Geographic Information Systems (GIS) technologies. The approach is staged, firstly determining the PnR station choice as a function of the attractiveness of a train station and the cost of access between the origin (such as a suburb) and the destination of a trip (such as the Perth CBD). Linear referencing method is then applied to re-define the origins to train stations based on the derived station choice probability. Finally, the spatial boundary of a catchment area is determined according to the adjusted origins, using GIS technologies. The model outputs were evaluated against licence plate survey of station users, where the Kappa coefficient (0.74) and overall accuracy (0.88) statistic suggested that the model's results are robust. The paper then shows how catchment area data can be used to better manage travel demand and plan design solutions aimed at increased accessibility to train stations.     

A multimodal approach to assessing accessibility of a high-speed railway station

In China, accessibility has been profoundly improved by the large-scale construction and operation of high-speed rail (HSR), with far-reaching implications for population flows and socioeconomic development. As a novel attempt to compare the shortest travel times, accessible regions, service populations, and population potential of one- to four-hour isochrones under four scenarios in Tanggu Railway Station (i.e., base scenario, hypothetical scenario 1, hypothetical scenario 2, and actual scenario), this paper analyses three factors' influences on and contributions to accessibility change: the advent of HSR, conventional railway route adjustment, and road network improvement. The results indicate that station accessibility significantly improved from 2007 to 2012. HSR has not only brought a time-space contraction effect to the region from the station to the north-western area but also strengthened interactions among different regions. Due to the reduction of some conventional railway routes, the shortest travel times from the station to the north-eastern areas have slightly increased. Although this factor has some negative effects, it has not affected the ascending trend of enhanced accessibility. Road network improvement is identified as a key factor with balanced impacts on all four-hour isochrones. The results of this study generate supportive information for the planning and construction of HSR stations and networks and provide references for comprehensive transport policymaking.     

Impacts on accessibility of China’s present and future HSR network

Although the construction of China’s high-speed rail (HSR) network only started in 2003, the network is already the largest in the world. This paper analyses the impact of the evolving HSR network on the accessibility by HSR and conventional ground transport of 333 prefecture-level cities and 4 municipalities. This paper employs three indicators of accessibility, and analyses three Scenarios. It shows that the HSR network will bring about substantial improvement in accessibility, and lead to national time–space convergence, but will also increase the inequality of nodal accessibility between eastern, central, and western regions, between cities with different sizes of population (excluding the case of the daily accessibility indicator) and between cities that differ in the shortest distance to HSR stations. The HSR network enlarges internal disparities in each of the regions and the five types of cities. The internal inequality of nodal accessibility in all three Scenarios generally increases from the eastern region via the central region to the western region, as well as from very large cities to small cities, varying inversely with the level of economic development and population size. Spatially, accessibility increases generally conform to the distance decay rule but with minor fluctuations. The 50 cities with the largest increases in accessibility are mostly located 50 km or less away from HSR stations and have populations of over 3 million, with the smaller ones located along HSR lines or around large cities such as Beijing, Shanghai, and Guangzhou. As time progresses, the planned HSR network will result in more balanced development, but regional disparities in accessibility will still be greater than before the construction of the HSR.     

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

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

速度等级组合列车的双线铁路站间距合理性研究

合理确定双线铁路站间距,可以在满足运营需要通过能力的同时,适当减少中间站的设置数量,满足铁路运输需要。以图解法和分析计算法为基础,考虑列车速度组合、列车铺画顺序、列车连发对数和列车间隔时间等因素对合理站间距的影响,采用均衡铺画和集中铺画方法,分析列车运行图周期的时间构成,计算3种速度等级列车组合下的双线铁路站间距。经实例验证合理站间距计算方法的合理性,得出双线铁路区段在3种速度等级列车组合情况下的合理站间距。     

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

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

Evaluating accessibility impacts of the proposed America 2050 high-speed rail corridor for the Appalachian Region

Transportation improvements are often considered to be precursors of economic growth. This paper examines industry-specific ‘attractiveness’ due to changes in the transportation network for 23 counties in the Appalachian Region. The network improvements result from new highway construction and the proposed America 2050 High-Speed Rail (HSR) plan for the Piedmont Atlantic Megaregion. The impacted counties that are proximate to five HSR stations (Birmingham, Atlanta, Greenville, Charlotte, and Greensboro) are studied for potential accessibility changes between the years 2002 to 2035. The impacts are examined with respect to six key industry sectors found around the proposed HSR stations: manufacturing; retail; construction; mining, quarrying, oil and gas extraction; health-care services; and all other remaining industries combined. The analysis shows that, for transportation improvements with highways only (and no HSR), a decrease in accessibility for all the impacted counties occurs for the six industry sectors examined in the future year of 2035. The HSR speed of 150 miles per hour is found to be adequate enough to cause positive changes in potential accessibility of the directly impacted counties containing the Birmingham and Greenville HSR stations. With combined transportation network improvements from both highway construction and the new 150 mph HSR line, counties around the Atlanta and Greensboro HSR stations would see accessibility increases in 2035 compared to 2002 with respect to five industry sectors: manufacturing; retail; construction; health-care services; and all other remaining industries combined. However, accessibility changes with respect to mining, quarrying, oil and gas extraction would be positive specifically only for the indirectly impacted counties around the Atlanta HSR station and the county containing the Greenville HSR station. This clearly shows differences in the spatial distribution of attractiveness for different industry sectors across the impacted counties along the HSR corridor. Thus, this exploratory analysis could serve as an aid to proactive public policy decision-making for large-scale transportation network improvements, such as the HSR, in understanding and improving economic activities for different industry mixes across other regions of the United States.     

The European high-speed train network: Predicted effects on accessibility patterns

The principal aim of this paper is to evaluate the impact of the future European high-speed train network on accessibility, by reducing time distance between places and modifying their relative location. We compare the current situation with that foreseen for the year 2010, according to the Outline Plan of the European High-Speed Train Network, in order to analyse which areas will most benefit from construction and improvement of the infrastructure. It is hypothesized that the high-speed train will certainly bring the peripheral regions closer to the central ones, but will also increase imbalances between the main cities and their hinterlands. A weighted average distance indicator is applied for this purpose. This measure identifies the spatial distribution of accessibility in the area of study, emphasizing the infrastructure effects, and locates accessibility changes at the European level. A Geographic Information System (GIS) has been used to carry out this study.     

Perceived accessibility: What it is and why it differs from calculated accessibility measures based on spatial data

Accessibility is usually evaluated using indicators calculated from spatial data. However, perceived accessibility, defined as the perceived potential to participate in spatially dispersed opportunities, is often poorly reflected by these calculated measures. This paper sets out to explain the mechanisms that lead to these mismatches. A conceptual model is constructed to establish what factors shape perceived accessibility. A schematic framework shows that mismatches between a calculated indicator and perceptions can stem from inaccuracies in awareness as well as from inaccuracies in the measure if the measure fails to take account of the subjective evaluations of accessibility components. When evaluating the performance of land-use and transport system configurations, calculated measures based on spatial and transport data only serve as proxies for how accessibility is actually experienced. This paper argues that bringing perceived accessibility to the fore of accessibility-based planning, by acknowledging and evaluating potential mismatches with calculated accessibility indicators, will advance the evolution from mobility-based to accessibility-based planning.     

Exploring the impact of built environment factors on the use of public bikes at bike stations: Case study in Zhongshan,China

Many countries have implemented public bike systems to promote sustainable public transportation. Despite the rapid development of such systems, few studies have investigated how built environment factors affect the use of public bikes at station level using trip data, taking account of the spatial correlation between nearby stations. Built environment factors are strongly associated with travel demand and play an important role in the success of public bike systems. Using trip data from Zhongshan's public bike system, this paper employed a multiple linear regression model to examine the influence of built environment variables on trip demand as well as on the ratio of demand to supply (D/S) at bike stations. It also considered the spatial correlations of PBS usage between nearby stations, using the spatial weighted matrix. These built environment variables mainly refer to station attributes and accessibility, cycling infrastructure, public transport facilities, and land use characteristics. Generally, we found that both trip demand and the ratio of demand to supply at bike stations were positively influenced by population density, length of bike lanes and branch roads, and diverse land-use types near the station, and were negatively influenced by the distance to city center and the number of other nearby stations. However, public transport facilities do not show a significant impact on both demand and D/S at stations, which might be attributed to local modal split. We also found that the PBS usage at stations is positively associated with usage at nearby stations. Model results also suggest that adding a new station (with empty capacity) within a 300 m catchment of a station to share the capacity of the bike station can improve the demand-supply ratio at the station. Referring to both trip demand models and D/S models, regression fits were quite strong with larger R² for weekdays than for weekends and holidays, and for morning and evening peak hours than for off-peak hours. These quantitative analyses and findings can be beneficial to urban planners and operators to improve the demand and turnover of public bikes at bike stations, and to expand or build public bike systems in the future.     

Exploring public transport equity between separate disadvantaged cohorts: a case study in Perth,Australia

This paper explores the equity distribution of public transport for three separate disadvantaged cohorts including elderly residents, low-income households and no-car households for Perth, Western Australia. It also undertakes a city-wide equity analysis of Perth and compares this with a published analysis for Melbourne. Overall the public transport distribution of the three socially disadvantaged groups was identified to be less equitable when compared to the population as a whole. The elderly had the most inequitable distribution of population relative to other cohorts. Perth’s population exhibits a 0.52 Gini coefficient suggesting a relatively unequal spatial distribution of services to the population. However, this is much better than Melbourne (at 0.68). Results imply that 70% of Perth’s population have only 33% of services supplied, whilst in Melbourne this figure was 19%. Policy implications and areas for future research in this field were identified.     

Detecting urban road network accessibility problems using taxi GPS data

Urban population growth and economic development have led to the creation of new communities, jobs and services at places where the existing road network might not cover or efficiently handle traffic. This generates isolated pockets of areas which are difficult to reach through the transport system. To address this accessibility problem, we have developed a novel approach to systematically examine the current urban land use and road network conditions as well as to identify poorly connected regions, using GPS data collected from taxis. This method is composed of four major steps. First, city-wide passenger travel demand patterns and travel times are modeled based on GPS trajectories. Upon this model, high density residential regions are then identified, and measures to assess accessibility of each of these places are developed. Next, the regions with the lowest level of accessibility among all the residential areas are detected, and finally the detected regions are further examined and specific transport situations are analyzed.By applying the proposed method to the Chinese city of Harbin, we have identified 20 regions that have the lowest level of accessibility by car among all the identified residential areas. A serious reachability problem to petrol stations has also been discovered, in which drivers from 92.6% of the residential areas have to travel longer than 30 min to refill their cars. Furthermore, the comparison against a baseline model reveals the capacity of the derived measures in accounting for the actual travel routes under divergent traffic conditions. The experimental results demonstrate the potential and effectiveness of the proposed method in detecting car-based accessibility problems, contributing towards the development of urban road networks into a system that has better reachability and more reduced inequity.     

Future accessibility impacts of transport policy scenarios: Equity and sensitivity to travel time thresholds for Bus Rapid Transit expansion in Rio de Janeiro

The accessibility impacts of transport projects ex-post implementation are generally evaluated using cumulative opportunity measures based on a single travel time threshold. Fewer studies have explored how accessibility appraisal of transport plans can be used to evaluate policy scenarios and their impacts for different social groups or examined whether the results of project appraisals are sensitive to the time threshold of choice. This paper analyzes how different scenarios of full and partial implementation of the TransBrasil BRT project in Rio de Janeiro (Brazil) will likely impact the number of jobs accessible to the population of different income levels. The analysis is conducted under various travel time thresholds of 30, 60, 90 and 120 min to test whether the results are sensitive to the boundary effect of the modifiable temporal unit problem (MTUP). Compared to a partial operation scenario, the full implementation of TransBrasil that extends this corridor into the city center would lead to higher accessibility gains due to network effects of connecting this BRT to other transport modes. Nonetheless, the size of the accessibility impacts of the proposed BRT as well as its distribution across income classes would significantly change depending on the time threshold chosen for the accessibility analysis. Considering cut-off times of 30 or 60 min, both scenarios of TransBrasil would lead to higher accessibility impacts in general and particularly for low-income groups, moving Rio towards a more equitable transportation system. However, under longer thresholds of 90 and 120 min, an evaluation of this project would find much smaller accessibility gains more evenly distributed by income levels. The paper highlights how time threshold choice in cumulative opportunity measures can have important but overlooked implications for policy evaluation and it calls for further research on the MTUP in future transport and mobility studies.     

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.     

Measuring relative non-motorized accessibility to retail activities

Accessibility planning is a crucial alternative to mobility planning for reaching sustainable outcomes. Although there is a vast literature on accessibility, less attention is paid to accessibility as a relative concept, i.e., its relationship with the socio-economic characteristic of the population. While accessibility is known to vary by location, it also changes as a consequence of differences in individual willingness to reach destinations by certain transport modes. Using the city of Zaragoza, Spain as a case study, this paper evaluates relative non-motorized accessibility (walking and cycling) to three types of retail activities: daily, weekly, and incidental. First, a clustering process is used to identify four population groups according to their socio-economic characteristics (the young employed; the young unemployed; seniors and adults). Second, distance-decay functions based on time-willingness to reach retail destinations by non-motorized modes are compared between the four clusters of population. Third, relative accessibility maps based on gravity-based models are elaborated, highlighting places that exhibit statistical differences between the population clusters. The results indicate that willingness to reach retail stores on foot by seniors (>65?years old) was significantly different from the rest of groups analyzed, providing additional insights on how relative accessibility measurements can anticipate potential social exclusion risks.     

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

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

突发大客流在城市轨道交通网络中的传播机理

根据突发大客流在城市轨道交通车站的作业性质和特点,将城市轨道交通网络中的车站分为发生站、换乘站和中间站。在此基础上,通过站台候车区的乘客密度、到达列车的剩余载客能力、站台候车乘客数和乘客上车效率等因素,构建站台候车区乘客密度影响模型和列车运行延误时间模型,并总结出突发大客流在城市轨道交通网络中的传播机理。从车站服务水平和列车运行影响两个方面对突发大客流传播的影响因素及相应的调整措施进行分析。