Transportation subsidies, economic efficiency, equity, and public policy

According to many environmentalists, the U.S. transportation sector is being subsidized by federal, state, and local governments. Whether or not road users are, in fact, paying the cost of using roads is a critical issue in supporting sustainable transportation. Subsidies increase road consumption above levels that would otherwise be dictated by the market. This paper compares different estimates of transportation subsidies, noting their strengths and weaknesses. Following this discussion, the issue of transportation as a public good is covered. How economic efficiency and equity are considered depends in large part on the role of transportation in society. If transportation is deemed a public good, then alternative evaluation criteria must be applied. If not, then economic efficiency would need to be considered. Both efficiency and equity could be enhanced by a pollution tax. Such a measure would improve equity by charging users for the pollution they generate. In addition, economic efficiency could be enhanced by internalizing the environmental externalities associated with transportation. This study, compares different estimates of transportation subsidies as a prelude to discussing economic efficiency and equity issues. The study does not develop a definitive answer to the problem of transportation subsidies, but rather highlights the important public policy issues that exist within this arena.     

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.     

A data model for multi-dimensional transportation applications

The distinctive data management needs of transportation agencies in developing transportation-based applications dictate the presence of essential elements that are beyond existing transportation location referencing system data models. These elements include multi-dimensional location referencing, multiscale representation, navigation, and temporal GIS. This paper looks at the foundation for these elements, describes the characteristics of these elements and offers solutions through a transportation-based multi-dimensional data model. By managing data expressed in one to four dimensions, the Multi-Dimensional Location Referencing System (MDLRS) data model allows organizations to implement improved solutions for transportation systems using advanced spatial technologies (e.g. GPS).     

区域交通基础设施可达性研究进展

随着中国区域交通基础设施快速发展,可达性研究受到学界与规划界广泛关注.本文通过梳理近20 年来国内外区域交通基础设施可达性研究的发展脉络,从可达性时空变化及其地域效应方面总结国内外区域交通可达性研究的各自特点与发展方向,判断未来国内相关研究主题.综合比较可知,区域交通可达性的空间格局与时空演变研究仍是国内外交通地理学的研究热点问题.国外研究评价指标丰富,空间分辨率不断提高,分析技术方法日益多样,研究内容更趋于多元化,不断拓宽了可达性研究与应用领域.国内研究发展快,但研究指标体系有待完善,空间分辨率仍有待提高,亟待考虑交通需求与政策干预等现实因素.     

上海中心城区生活垃圾收运处置规划的多维度分析

生活垃圾收运处置规划是城市环卫规划与管理的重要内容,本文在剖析传统生活垃圾收运处置规划模式的基础上,从政策机制、规划设计、技术管理、实际操作4个维度探讨了上海中心城区生活垃圾收运处置规划的多维度分析方法,并以普陀区为例进行了实证研究。研究结果表明,多维度分析方法有助于将循环经济思想融入生活垃圾收运处置各个环节,促进其流程和步骤的有效衔接,在上海中心城区具有较好的应用前景。     

Spatial Scale and Population Assignment Choices in Environmental Justice Analyses1

Environmental justice laws protect certain populations against discriminatory actions that may result from a myriad of enterprises, including transportation activities. Previous environmental equity studies examining the effects of transportation‐engendered externalities have been criticized on several points, including (1) that the choice of a reference population for comparison to the criterion variable may influence the outcome of research results and (2) that the selection and use of inappropriate methodologies intended to identify and characterize populations may foreordain research outcomes. This article examines the potentially confounding effects of selected spatial scale and population assignment strategies as applied to a study of excessive noise levels at a large Midwestern airport, finding that reported outcomes can vary significantly as a function of methodological choices.     

多元交通视角下异质旅游流分布特征及其空间共轭关系

异质性是旅游流研究亟待拓展的内容。以北京、武汉和西安为案例客源地,基于2017年获取的城市居民出游行为大样本问卷数据,利用数理统计法、地图分析法等方法,从客源地视角对自驾车、火车、飞机3种交通方式旅游流的分布特征进行研究,研究发现：① 随着出游交通时间的增加,自驾旅游流呈指数衰减,火车和飞机旅游流呈正偏态分布。② 3种交通方式旅游流的空间分布格局存在差异。自驾高到访率区域围绕在客源城市周围;火车与飞机高到访率区域远离客源城市。③ 不同交通方式黄金出游空间具有共轭性,距客源城市球面距离0~400 km区域为自驾黄金出游空间,400~1 200 km乘火车（包括动车和高铁）6.00 h可达区域为火车黄金出游空间,1 200~2 600 km区域为飞机黄金出游空间。基于研究结果,提出了异质交通方式黄金出游空间共轭模型,刻画了自驾车、火车、飞机3种主要交通方式黄金出游空间的位置和共轭关系。     

Bridging equity? Washington,D.C.’s new elevated park as a test case for just planning

In the last decade, justice has been revived as a primary criterion for the analysis and evaluation of planning policies. This paper continues this line of research by examining a proposed redevelopment project in Washington, D.C. that sets equitable development as its goal . The proposed 11th Street Bridge Park would be a top-notch elevated park, physically and symbolically connecting D.C’s wealthy west with the disadvantaged east. The project is managed by a nonprofit organization and seemingly stands out in its progressive vision: An Equitable Development Plan has been developed in an attempt to secure the future of the local residents in light of the neighborhood's anticipated gentrification. However, preliminary findings show that despite explicit commitment to equity, the planning of the park also resurfaces racial and class tensions . The analysis of procedural and substantive aspects of justice in this case suggests that issues of recognition, power and representation are instrumental to fully understand urban (in)justices.     

AFV refueling stations and the complexity of freeway intersections: the scale dependency of network representation

As interest for alternative fuel vehicles (AFVs) in urban areas continues to build, there has been a corresponding focus on the development of methods that can locate initial refueling stations on regional transportation networks in an optimal manner. Recent studies suggest that the behavior of early adopters of AFVs is consistent with the objectives of flow-capturing station location models. One outstanding issue with the further use of these models to locate AFV stations is the relationship between the relatively coarse geographic representation of regional transportation networks used in flow-capturing models and the complexity of the sites they recommend, which are often nodes that represent freeway intersections. Since AFV refueling stations cannot be built directly at freeway intersections, a network GIS method entitled the freeway traffic capture metric (FTCM) is developed to identify locations on proximate local street networks that can effectively capture all traffic passing through a freeway intersection. The FTCM considers deviation from a shortest travel path specifically through a freeway intersection as its metric of convenience for all possible travel routes that pass through it, computing a score for each candidate site on the nearby local street network. The FTCM is tested on nearly 45,000 candidate sites within one mile of 72 freeway intersections in greater Los Angeles, California. Locations that can capture all traffic passing through the nearby freeway intersection are shown to generally be near the intersection’s center, but not necessarily next to freeway entrances or exits. In total, 6.7% of possible station locations near these 72 freeway intersections are convenient for all traffic passing through them, and 22 out of the 72 freeway intersections lack such a site altogether. This indicates that there is high likelihood of inconsistency between regional modeling results and station location effectiveness if this scale dependency between coarse representations of transportation networks and the complexity of local street networks near freeway intersections is not considered when building initial AFV stations near these locations.     

Evaluating representation and scale error in the maximal covering location problem using GIS and intelligent areal interpolation

A common problem in location-allocation modeling is the error associated with the representation and scale of demand. Numerous researchers have investigated aggregation errors associated with using different scaled data, and more recently, error associated with the geographic representation of model objects has also been studied. For covering problems, the validity of using polygon centroid representations of demand has been questioned by researchers, but the alternative has been to assume that demand is uniformly distributed within areal units. The spatial heterogeneity of demand within areal units thus has been modeled using one of two extremes – demand is completely concentrated at one location or demand is uniformly distributed. This article proposes using intelligent areal interpolation and geographic information systems to model the spatial heterogeneity of demand within spatial units when solving the maximal covering location problem. The results are compared against representations that assume demand is either concentrated at centroids or uniformly distributed. Using measures of scale and representation error, preliminary results from the test study indicate that for smaller scale data, representation has a substantial impact on model error whereas at larger scales, model error is not that different for the alternative representations of the distribution of demand within areal units.     

机会公平视角下绍兴城市公园绿地可达性评价

以绍兴古城及周边地区为研究区域,利用居住建筑的空间分布来测算评价区域内常住人口空间分布;继而利用GIS工具来测量公园绿地服务范围,并统计出市民可享用公园绿地的选择机会的空间分布情况,从而在精细尺度上基于空间公平视角实现对公园绿地的可达性测量。研究表明,公园绿地服务范围内部存在着不公平现象,进而提出了相应的公园绿地布局优化策略。     

北京城区公共交通满意度模型与空间结构评价

以北京市城八氏的公共交通为切入点.探索了城市空间结构的评价分析方法.通过"公共交通可达性"指标.将城市实体空间结构的指标与居民对公共交通的满意度连系起来.建立了以满意度为目标的城市空间结构评价体系.并对提升城市空间结构的实体空间因子进行了实证分析.首先,对"公共交通可达性"的各项影响因子进行了梳理,从公共交通服务质量、区域经济特征、道路建设三个方面,提出了包括公交通达度、人口和经济集聚度、道路密度、区位指标等在内的城市公共交通可达性的评价指标体系.其次,构建了以居民满意度为因变量的公共交通可达性评价模型.分析定量揭示了公交站点配置、公交通达度、经济密度等凶素对了:城市空间结构的优化作用.同时分析表明.公共交通的优化需充分考虑不同属性的居民群体的空间分布规律.据此,从城市空间结构评价的角度分析了北京市公共交通中存在的问题,并提出如下建议:①市政交通规划的重点应放在五环以内地区;②实现800m公交站点服务面积全覆盖;③加强各地与市区重要功能节点的公共交通联系来提高其通达度;④根据居民的分布和属性特征出台相应的公交服务政策提高不同居民群体的公共交通满意度.     

Geographic Perspectives of Air Transportation

Past, present, and future research directions and advances in this highly dynamic research area of air transportation are reviewed with an eye toward geographers' contributions to the air transportation industry. The study of air transportation within the field of transportation geography and the larger discipline of geography is important as geographers use air transportation to help describe concepts such as connectivity and linkages, development patterns at various scales, and the global economy. This article takes three approaches in exploring geographers' contributions to research in the field: historical, publication outlets, and topic focus. The goal of the article is to commemorate the contributions of pioneer and current researchers in the field, and open to discussion future research paths in air transportation.     

Access,Equity, and Urban Greenways: An Exploratory Investigation

Recurring issues in the social sciences concern the distribution of public facilities such as parks and equity of access to them. Geographers have observed that access has perceptual as well as physical dimensions and that perceptions of difference can affect use of public space. This study explores the nature of greenways as public space and a set of issues related to equity of access to greenway trails in Indianapolis, Indiana. The study uses proximity as a measure of access and simple GIS analyses of census and other data to assess equality of access. Evidence is provided that suggests that minorities and the poor have disproportionate access to trails. It is also shown that populations adjacent to the trails differ and that the populations along particular trails are segregated. Spatial differences in trail populations are associated with historic land use patterns and population movements within the city. The implications of the findings of difference for use of the greenways system are explored. Implications for management of the greenways system—including achievement of the goal of linking neighborhoods—are also discussed.     

AN APPROACH TO REPRESENTING THE SPATIAL STRUCTURE OF THE INFORMATION SOCIETY

With recent advances in information and communications technologies (ICT), traditional conceptualizations and models of spatial interaction need updating. In a previous paper, this author developed an analytical framework that incorporated telecommunications capabilities as well as transportation modes and residential and work locations into a unified representation of the “geography of opportunities” (Shen, 1999). In this paper, the initial framework is extended by the inclusion in the formulation not only of employment opportunities, but also of other types of opportunities. Each type of opportunities is distributed among three components of geographic space: the physical space, the hybrid space, and the virtual space. The effects of ICT are captured by: (1) the saving of travel time for people who can partially substitute telecommunications for transportation as means to access opportunities in virtual and hybrid spaces and (2) the migration of opportunities from physical space to virtual and hybrid spaces. Individuals' position in the emerging spatial structure of the information society is measured in terms of accessibility to a wide range of economic and social opportunities. This new approach is shown to be an operational and promising analytical tool in a hypothetical setting. However, its refinement and application is currently constrained by the lack of systematically collected data on many aspects of the human geography. [Key words: telecommunications, human geography, spatial structure, spatial analysis.]     

Extending the conversation on socially engaged geographic visualization: representing spatial inequality in Buffalo,New York

This paper is situated at the intersections among GIS and geovisualization, critical social theory, and urban studies. It presents an analysis of housing segregation and unequal food and transportation access in Buffalo, New York. We demonstrate how the representation and examination of this socially complex multi-scalar issue benefits from deliberate, reflexive conversation between different critical social-spatial epistemologies. We begin with a relatively simple GIS analysis of spatial segregation and arrive through critical iteration at a more qualitatively nuanced cartogram which moves beyond representations of fixed space to reveal a much more relational situation—a case of “time-space expansion” in which the travel time needed to meet a basic daily need is much greater for the poor and people of color than it is for whiter, more affluent populations. We conclude by infusing this narrative with additional considerations from social theory to show how even a limited visualization such as ours might better critically engage broader social and discursive processes in and across urban space.     

Spatial Scale and Population Assignment Choices in Environmental Justice Analyses 1

Abstract

Environmental justice laws protect certain populations against discriminatory actions that may result from a myriad of enterprises, including transportation activities. Previous environmental equity studies examining the effects of transportation-engendered externalities have been criticized on several points, including (1) that the choice of a reference population for comparison to the criterion variable may influence the outcome of research results and (2) that the selection and use of inappropriate methodologies intended to identify and characterize populations may foreordain research outcomes. This article examines the potentially confounding effects of selected spatial scale and population assignment strategies as applied to a study of excessive noise levels at a large Midwestern airport, finding that reported outcomes can vary significantly as a function of methodological choices.     

Exploring the differential impacts of urban transit system on the spatial distribution of local and floating population in Beijing

The floating population has become the main driver of urban population excessive growth in China’s mega cities. Urban transit system (UTS) is a significant factor in population spatial distributions within urban areas, especially rapid and high-capacity transit systems. This paper analyzes the causal effects of the extension of expressways and subways between 2000 and 2010 in the Beijing Metropolitan Area (BMA), focusing on the group differences between the local residents and the floating population. Due to the endogeneity of transportation improvements and population growth, Instrumental Variable (IV) regression model is applied to avoid this problem. The results show the local residents increased in the inner suburbs but decreased in the city center, while the floating population increased in the majority areas. IV regression results show that the extension of urban transit systems had statistically significant impacts on population growth across the BMA. The results also show that the extension of urban subway system had more effects on the floating population than the local residents across the BMA. It is mainly caused by the rather low fare of urban subway system. This implies that the excessive subsidy on urban subway system could result in excessive floating population growth and residential differentiation, even residential segregation. Hence, it is necessary to plan and design reasonable and scientific urban transit systems in order to advance reasonable population size and promote residential integration. Moreover, the regional analysis shows that the effects of urban transportation improvements on the local residents are not statistically significant in the inner suburbs. It implies that urban transportation improvements had limited effects on inducing people to move to suburban areas and controlling center city’s population in Beijing. Therefore, it should be stressed the differentiated effects of urban transportation improvements on population distribution in the process of urban planning and population control.     

中国都市圈中运量型轻轨交通的发展问题研究

从都市圈的空间结构和交通需求的特点分析入手,讨论了中运量型轻轨交通在都市圈公共交通中的地位与作用。结合中国都市圈建设中有关轻轨公共交通发展的问题,指出发展以中运量型轻轨交通为骨干的城市公共交通是中国都市圈交通建设的重要方向,并对中国都市圈以中运量型轻轨交通为骨干的都市圈综合交通体系的规划建设提出了若干建议。     

城市道路与公共交通网络中心性对住宅租赁价格的影响研究——以北京市为例

住房市场化与较高住房需求带来住房价格的迅速提升,进而引发住房可负担性下降等问题,租赁住房逐步成为居民的另一主要择居方式。城市交通作为重要因素之一,对住宅租赁价格的影响仍需深入探讨。论文以北京市为例,运用交通网络中心性指标,研究道路网络及公共交通网络对住宅租赁价格影响的空间差异。结果表明：① 以出行时间为基础构建交通网络,公交网络总体拟合程度高于道路网络;公交网络中邻近中心性即相对可达性拟合程度最高,而道路网络中介中心性即中转功能拟合程度最高;② 城市中心-城市中部-城市外围的环状结构中,中心性影响程度存在空间差异,道路邻近中心性及公交各类中心性对城市中心及中部具有重要影响,城市外围主要受道路邻近中心性及介中心性影响;③ 基于拟合程度最高的公交网络邻近中心性的影响模式分析,综合交通枢纽、轨道交通换乘站点、轨道交通站点、重要地面公交站点等在城市中心及中部对租赁价格影响较高,而城市外围仅轨道交通站点及换乘站点影响较高;④ 道路设施网络与公交组织网络结构特性导向下的驱动力差异、交通网络各功能空间效应的区位指向、城市不同空间重要基础设施建设的外部效应差异促进了道路与公交网络中心性对租赁价格影响的空间分异。