广州市地铁对常规公交出行成本影响及其空间公平性研究

从时间与费用两个角度研究广州市地铁建设对公共交通可达性的影响及其影响的空间公平性。结果表明:① 加权时间与费用可达性均形成“核心-外围”的空间格局。通地铁后,南部郊区加权时间可达性变化率较大,花都区变化率最低;加权费用可达性高变率地区集中在地铁沿线及边缘地区。② 不乘地铁情境下,CBD等时圈呈同心圆状,80％的居民在50 min以及2元钱花费内能到达最近的商业综合体。乘地铁情境下等时圈沿着地铁网络延伸与扩散,80％的居民在30 min以及5元钱以内能到达最近的商业综合体。③ 无论是否乘坐地铁,出行时间的不公平程度都高于出行费用的不公平程度。番禺区的社区从地铁网络中时间可达性获益最多,最不公平的是白云区的社区,其绝对和相对变化较低;中心城区由于常规公交网络发达,地铁缩短的绝对出行时间较少,而变化率高。地铁对城市内中远距离出行性价比的影响最明显。     

Quantifying multi-modal public transit accessibility for large metropolitan areas: a time-dependent reliability modeling approach

The temporal dimensions of public transit accessibility have recently garnered an increasing amount of interest. However, the existing literature on transit accessibility is heavily based on oversimplified assumptions that transit services operate at deterministic speeds using predetermined timetables. These measurements may overestimate transit accessibility, especially for large metropolitan areas where inter- and intra-modal transfers are frequent. To handle travel time uncertainty, a multi-modal transit accessibility modeling approach is proposed to account for realistic variations in travel time and service reliability. The proposed approach is applied to the mapping of transit accessibility in Shenzhen (China), where transit services exhibit significant travel time variations over space and time. Compared to traditional transit accessibility measures, our method has been demonstrated to better capture intrinsic spatial and temporal accessibility variations with complex multi-modal transit networks. Normal distribution of inter-stop travel times and constant travel speed between GPS sampling points are assumed to simply the computation, which we consider to adjust in future studies to better quantify the dynamics of transit accessibility across space and time.     

中国省会城市高铁费用可达性及居民消费格局

高铁建设虽在较大程度上改善了城市间的时间可达性,但其高票价导致的旅行费用增加在一定程度上限制了人们对高铁的消费预期。从费用可达性和居民对高铁的消费能力两个方面,基于省会城市间2008和2015年的铁路最短旅行时间及相应的票价、城镇居民人均收入数据,采用平均旅行费用、高铁消费能力指数和高铁消费预期指数等指标对省际费用可达性及居民对高铁的消费能力和消费预期进行分析。主要研究结论为：①高铁不同程度上抬升了省会城市间的旅行费用,费用可达性空间格局从以郑州、济南为中心的核心—边缘型空间格局转变为以呼和浩特、太原为中心的核心—边缘型空间格局;②大多数城市的居民高铁消费能力得到了不同程度的提升,但高铁消费能力和消费预期都呈现出东中部优于西部和东北部地区的不均衡分布特征。本文可对优化高铁供给格局进而对提升高铁的利用效率具有一定的参考价值。     

Gender and Individual Access to Urban Opportunities: A Study Using Space–Time Measures

Conventional accessibility measures based on the notion of locational proximity ignore the role of complex travel behavior and space–time constraints in determining individual accessibility. As these factors are especially significant in women's everyday lives, all conventional accessibility measures suffer from an inherent “gender bias.” This study conceptualizes individual accessibility as space–time feasibility and provides formulations of accessibility measures based on the space–time prism construct. Using a subsample of European Americans from a travel diary data set collected in Franklin County, Ohio, space–time accessibility measures are implemented with a network-based GIS method. Results of the study indicate that women have lower levels of individual access to urban opportunities when compared to men, although there is no difference in the types of opportunities and areas they can reach given their space–time constraints. Further, individual accessibility has no relationship with the length of the commute trip, suggesting that the journey to work may not be an appropriate measure of job access.     

The benefits of a high-resolution analysis of transit accessibility

Accessibility is an important consideration in sustainable mobility policies, particularly for transit users. Measures suggested in the literature are based on coarse aggregate spatial resolution of traffic analysis zones that is sufficient for managing car travels only. To reflect a human door-to-door travel, transit accessibility demands an explicit view of the location of origin, transit stops and destination, as well as of the temporal fit between transit lines timetable and traveler’s needs. We thus estimate transit accessibility based on mode-specific travel times and corresponding paths, including walking and waiting, at the resolution of individual buildings and stops. Car accessibility is estimated at a high resolution too. A novel representation of transit network as a graph is proposed. This representation includes all modal components of a transit travel – walking, waiting at a stop, transit ride, transfers between lines, thus enabling unified view of a travel, regardless of mode. The use of modern high-performance graph database allows construction of high-resolution accessibility maps for an entire metropolitan area with its 100–200 K buildings. The application is tested and applied in a case study involving the evaluation of the 2011 bus line reform in the city of Tel Aviv. Specifically, we demonstrate that while the reform increased the average accessibility for the entire city the increase was not uniform with different areas of the city experiencing different absolute accessibility by transit and relative accessibility in comparison to car travel. The bus reform did in fact benefit travelers that experienced low relative accessibility, but the benefits are mainly accruing to longer trips. Our approach and computational methods can be employed for directly investigating the impacts of transportation infrastructure investments.     

Estimating the effect of turn penalties and traffic congestion on measuring spatial accessibility to primary health care

Geographic variations in spatial accessibility to public resources, such as health care services, raise important questions about the efficiencies and inequities of the processes that determine where these services are located. Spatial accessibility can be measured many different ways, but many of methods in use today involve some measure of travel cost (in time or distance). In this study we explore a simple methodological question: how much are models of spatial accessibility influenced by the precise metric of travel cost? We address this question by comparing spatial accessibility to primary care physicians for two different methods of calculating travel cost (in time) on a street network: free-flow travel time and congested with turn penalties travel time—which augments free-flow travel times with the burden of traffic congestion and traffic intersection controls. We consider the effect of these two metrics of travel cost on a gravity-based measure of spatial accessibility to primary health care services in Edmonton, Alberta, Canada. Our results suggest that while travel times between locations of demand and locations of primary care providers greatly differ based on how travel cost is calculated, the gravity-based measure of spatial accessibility provides similar information for both travel cost metrics. Using congested with turn penalties travel time can be an onerous addition to the analysis of spatial accessibility, and is more useful for measuring absolute travel time rather than modeling relative spatial accessibility.     

Comparing Measures of Accessibility to Urban Supermarkets for Transit and Auto Users

Research on access to healthy foods often emphasizes the spatial proximity of residents to food stores like supermarkets as a way to gauge overall accessibility. Much of the literature has focused on locating the closest facility, assuming that access to one food store is sufficient. Given evidence that access to multiple healthy food stores can improve diets, however, this article examines how closest facility measures differ from cumulative opportunity accessibility measures across space in a medium-sized U.S. city. Differences in access between automobile and transit riders, using realistic travel time costs, are also considered. Results demonstrate that the two types of accessibility measures produce different accessibility geographies and that there are disparities in access for those dependent on transit. These findings indicate that researchers should carefully consider whether access to one supermarket opportunity is enough and pay special attention to the mode residents rely on to access food.     

Bringing Time Back In: A Study on the Influence of Travel Time Variations and Facility Opening Hours on Individual Accessibility

Although recent studies of individual accessibility have used detailed representations of urban street networks, unrealistic measures of travel time based on assumptions about constant travel speeds through the network were often used. Utilizing constant travel times does not allow for daily congestion and assumes that the effects of congestion are uniform throughout the city and affect all people equally. This research measures individual space‐time accessibility in order to show that the incorporation of locally specific travel times within a street network allows a significant increase in the ability to realistically evaluate individual accessibility within cities. The results show that the accessibility of individuals within cities is not homogenous, and neither does access to employment or shopping opportunities vary according to common expectations about urban form and human behavior. Instead, the role of distance in predicting accessibility variations within cities is quite limited. This article also shows that incorporating time into accessibility measures in the form of congestion and business hours leads to additional (and highly spatially uneven) reductions in accessibility, revealing that the temporal dimension is very important to accurately assessing individual accessibility.     

Bringing Time Back In: A Study on the Influence of Travel Time Variations and Facility Opening Hours on Individual Accessibility

Although recent studies of individual accessibility have used detailed representations of urban street networks, unrealistic measures of travel time based on assumptions about constant travel speeds through the network were often used. Utilizing constant travel times does not allow for daily congestion and assumes that the effects of congestion are uniform throughout the city and affect all people equally. This research measures individual space-time accessibility in order to show that the incorporation of locally specific travel times within a street network allows a significant increase in the ability to realistically evaluate individual accessibility within cities. The results show that the accessibility of individuals within cities is not homogenous, and neither does access to employment or shopping opportunities vary according to common expectations about urban form and human behavior. Instead, the role of distance in predicting accessibility variations within cities is quite limited. This article also shows that incorporating time into accessibility measures in the form of congestion and business hours leads to additional (and highly spatially uneven) reductions in accessibility, revealing that the temporal dimension is very important to accurately assessing individual accessibility.     

从区域一体化看融合交通——以粤港澳大湾区和港深广高铁线为例

高铁的网络化规划和发展为粤港澳大湾区内居民跨城活动提供便捷的快速公交式服务,是粤港澳大湾区形塑“一小时生活圈”的重要支撑。高铁站与城市公共交通的接驳在高铁出行链中占据重要位置,对更好发挥高铁时空压缩效应、提升居民高铁出行满意度、增加高铁出行选择及载客量具有重要意义。本文结合融合交通理论与旅客换乘经历,提出高铁站与城市公共交通接驳理论框架与实地观察指标,并应用到广深港沿线香港西九龙站、深圳北站、广州南站的观察式调研中,分析和对比3个高铁站的公共交通接驳表现。研究发现：在信息衔接层面,香港西九龙站展现出更好的国际化形象与对特殊人群的人文关怀;在设施和服务衔接层面,深圳北站与香港西九龙站以商场作为公共交通换乘点/路线连接点的设计,优化了换乘环境;在车票制度衔接层面,广州南站与深圳北站更好运用信息化技术,便利换乘服务。最后,基于调研结论提出相关建议以提升高铁站点城市公共交通接驳水准,促进粤港澳大湾区发展。     

北京公交就业可达性及其地区和人群差异

运用经济普查、人口普查数据和基于百度地图的公交出行时间数据,分析北京都市区基于公共交通的就业可达性及其在城市不同人群和地区间的差异。结果表明：北京都市区的居民可在60分钟内通过公共交通到达18.3%的都市区工作岗位,这比美国100个最大的都市区的平均就业可达性水平要高,接近于美国纽约都市区的就业可达性水平。同时,由于就业郊区化程度有限和以中心—放射式布局的公交网络,北京都市区内的公交就业可达性存在着巨大的区域差异,中心城区的就业可达性远远高于郊区。此外,人口居住的郊区化程度远远高于就业的郊区化程度,导致北京都市区宏观层面的职住不平衡。随着人口居住郊区化程度的提高,公共交通如何服务居住日益分散的人口,提高就业可达性,是一项巨大的挑战。研究还发现,由于城市中心区的大部分就业为高技术的就业岗位,因此高受教育程度人口能更多地享受目前公共交通系统的便利,而受教育程度低的人口和外来人口公交就业可达性较低。为解决弱势群体所面临的就业可达性的不平等问题,需要更多的规划与政策干预。     

PPGIS approach for defining multimodal travel thresholds: Accessibility of popular recreation environments by the water

It is essential to ensure equal accessibility to services, such as sport and recreation facilities or green and water environments. Differences in accessibility can potentially cause negative health and social welfare implications. Accessibility and service area analyses from the perspective of access equality are typically rather simple. They are often based on arbitrary travel-distance thresholds and made only with a single mode of transport in mind. Thus, they exclude the multidimensional nature of accessibility where individuals' travel behavior and perceived accessibility also play an important role. In this paper, a PPGIS method was used to empirically investigate distances and durations that respondents travel with different modes of transport to access popular water environments. Service area analyses were built on person-based and objectively measured threshold values that not only take into account the spatio-temporal elements of transport networks and a land use component but also recognize the requirements and preferences of individuals and their capacity to access and participate. The results showed that the most common mode of transport to access waters is walking. Generally, the residents travel by foot for 1.7 km to access water environments. Cars were found as the second most common mode of transport used, and most of the popular water environments are accessible by car from every corner of the study area in a given travel threshold time. The results demonstrate the importance of deriving local parameters and the potential of the PPGIS approach for accessibility and service area delineation.     

区域综合交通可达性评价——以安徽省为例

从安徽省省域、县域、省域内地区间的开放性、两种费用成本以及考虑区域社会经济因素的吸引机会六种角度评价安徽省城镇可达性,揭示了安徽省城镇不同指标下的可达性空间分异规律,并建立了一个综合可达性指数模型,进一步得到安徽省城镇的综合可达性空间格局。研究表明:安徽省城镇全域时间可达性格局大体是以合肥为中心向外沿伸展但并没有构成规则的同心圈层结构;局域时间可达性格局南北差异明显,南部和西南部可达性较差,北部较好;邻域分析中把城镇分为严重萎缩型、急剧扩张型、基本稳定型和上下浮动型四种;最短路径的费用成本空间分布上呈现内核为东北向月亮湾形的圈层;最小费用成本分析得到城镇可达性空间上有明显的铁路交通指向性;吸引机会指数则表明吸引机会高的城镇在空间上呈现人民币符号"￥"形;综合可达性指数略显城镇间南北对称,但在皖南山区不遵循此规律。最后,针对路网布局的一些弊端提出了相应的建议。     

Measuring place-based accessibility under travel time uncertainty

Travel time uncertainty has significant impacts on individual activity-travel scheduling, but at present these impacts have not been considered in most accessibility studies. In this paper, an accessibility evaluation framework is proposed for urban areas with uncertain travel times. A reliable space-time service region (RSTR) model is introduced to represent the space-time service region of a facility under travel time uncertainty. Based on the RSTR model, four reliable place-based accessibility measures are proposed to evaluate accessibility to urban services by incorporating the effects of travel time reliability. To demonstrate the applicability of the proposed framework, a case study using large-scale taxi tracking data is carried out. The results of the case study indicate that the proposed accessibility measures can evaluate large-scale place-based accessibility well in urban areas with uncertain travel times. Conventional place-based accessibility indicators ignoring travel time reliability can significantly overestimate the accessibility to urban services.     

Modeling Spatial Accessibility of Immigrants to Culturally Diverse Family Physicians

This article uses accessibility as an analytical tool to examine health care access among immigrants in a multicultural urban setting. It applies and improves on two widely used accessibility models—the gravity model and the two-step floating catchment area model—in measuring spatial accessibility by Mainland Chinese immigrants in the Toronto Census Metropolitan Area. Empirical data on physician-seeking behaviors are collected through two rounds of questionnaire surveys. Attention is focused on journey to physician location and utilization of linguistically matched family physicians. Based on the survey data, a two-zone accessibility model is developed by relaxing the travel threshold and distance impedance parameters that are traditionally treated as a constant in the accessibility models. General linear models are used to identify relationships among spatial accessibility, geography, and socioeconomic characteristics of Mainland Chinese immigrants. The results suggest a spatial mismatch in the supply of and demand for culturally sensitive care, and residential location is the primary factor that determines spatial accessibility to family physicians. The article yields important policy implications.     

Youth Mobility and Territorial Disparities: An Analysis of Urban and Rural Barcelona

Travel behavior of the present generation of youths is being increasingly explored due to their relevance in shaping future accessibility needs and mobility habits. The present study offers an original perspective on this topic by identifying territorial disparities that emerge in youth mobility patterns in rural and urban areas. Unlike most previous research, we propose taking a global view on mobility by analyzing all trip purposes and transportation modes. This is conducted by analyzing a comprehensive mobility survey in the Barcelona Metropolitan Region, which provides data on mobility engagement, trip purposes, modal split, travel times and territorial differences. In general, youngsters account for larger daily travel times than older adults, present a higher attachment to public transportation and walk less on a daily basis. These differences are enhanced in rural territories, where while older adults overcome accessibility issues with higher use of the private vehicle, youngsters are more likely to invest larger travel times on transit.     

社会公平视角下深圳公园绿地可达性研究

公园绿地是城市中重要的绿色基础设施。针对传统可达性分析微观尺度研究不足和交通成本估计失真等问题,以深圳为例,采用公园绿地矢量数据和基于手机SDK（Software Development Kit,软件开发工具包）定位的人口数据作为供需数据源,基于住房分类数据以城中村、保障房、商品房居民划分社会群体,利用改进的高斯两步移动搜寻法计算得到居住小区尺度的公园绿地可达性社会公平情况。研究发现：① 深圳公园绿地可达性存在社会分异：商品房和城中村可达性较好;公租房和安居房社区公园可达性差;人才住房仅对社区公园可达性高;② 驾车可达性最均衡,公共交通方式下不同住房群体间的可达性差异较大。研究补充了中国城市公园绿地可达性社会公平研究的不足,改进了小尺度可达性研究的数据与方法,为公园绿地规划体系提供反思,并可为深圳城市发展提供政策依据。     

基于感知形象调查的沙漠旅游行为意向研究

近年来,沙漠旅游呈现蓬勃发展之势。应用问卷调查法对国内居民的沙漠感知形象进行调查,在此基础上进一步对其沙漠旅游行为意向进行研究。结果表明,沙漠旅游具有广阔的市场前景,人们对沙漠旅游十分向往,愿意支付较高的旅游费用并花费较长的旅游时间,但对沙漠的感知形象支离破碎,且对已开发的沙漠旅游景区认知度较低。研究还发现,市场营销力度不够和交通可达性差是阻碍目前中国沙漠旅游业发展的主要因素。提出推动中国沙漠旅游快速发展的3点建议,即丰富旅游产品体系,重点发展观光旅游;塑造鲜明旅游形象,加大市场营销力度;提高交通可达性,完善旅游配套设施。     

Disparities in Spatial Accessibility of Pharmacies in Baton Rouge,Louisiana

This study examines spatial accessibility of pharmacies in Baton Rouge, Louisiana. Two popular geographic information systems (GIS)—based methods are compared: the proximity method uses the distance (travel time) from the nearest pharmacy, and the two‐step floating catchment area (2SFCA) method considers the match ratio between providers and population as well as the complex spatial interaction between them. The study indicates that disproportionally higher percentages of African‐Americans are in areas with shorter travel time to the nearest pharmacies than whites, but suffer from poorer accessibility measured by the 2SFCA method—that is, fewer pharmacies per 10,000 residents. Seniors, particularly those of seventy‐five years or older, tend to be disproportionally concentrated in areas that not only are closer to pharmacies, but also have more pharmacies per 10,000 residents. The two methods used in the study capture different elements in spatial accessibility: one being physically close to a facility and another adding the crowdedness in service. Both properties can be valuable for residents. The two may not always coincide with each other in spatial variability, as it is the case for racial disparity in our study area. However, when they do, as in the case for seniors, it may imply a true (dis)advantage for a demographic group in terms of both properties of spatial accessibility.     

THE IMPACT OF CHANGES IN PRICING POLICY UPON TRANSIT RIDERS OF VARYING AGES IN CHICAGO *

The elderly and young represent a significant segment of the transit-dependent ridership in metropolitan areas. The impacts of a change in pricing structure and transfer policy upon these groups are examined using survey data generated from riders of the Regional Transportation Authority in Chicago before and after a major restructing of fares and transfer policy. Results indicate that the elderly and young differ from the general population of respondents in their sensitivity to these changes. Moreover, it appears that the restructuring of fares did not adversely affect ridership patterns for these subgroups of transit users.