Integrating land use and transport practice through spatial metrics

Despite the growing development of tools that can integrate land use and transport, the desired integration is still illusive in daily practice. To address this gap, the current study uses spatial metrics, a set of methods traditionally used for studying changes in the spatial structure of landscapes, which are translated into the domain of transport planning. It examines how spatial metrics can be integrated into “Land Use Transport” strategy-making, and how useful they are according to the practitioners’ perceptions. A Light Rail Transit corridor in Granada (Spain) provides the empirical focus of this research. Land use characteristics such as: land use mixing, land use diversity and green areas connectivity were successfully studied using spatial metrics, and they were used to map three “Land Use Transport” strategies: (i) proximity dynamics and non-motorised modes; (ii) modal shift from cars to Light Rail Transit system; (iii) shared spaces between motorised and non-motorised modes. Practitioners perceived that spatial metrics could improve the “Land Use Transport” strategy-making process in comparison with traditional methods used in practice. However, certain shortcomings related to the usability of spatial metrics are also highlighted and discussed. This study concludes with a reflection on research challenges for adapting spatial metrics to transport practice.     

施工期仿真分析在船闸廊道工程中的运用

船闸廊道是混凝土裂缝易发部位,文章依托施桥三线船闸工程,采用大型有限元分析软件ANSYS对施工期廊道进行仿真分析,通过对施工期温度场、应力场的仿真计算和结构优化研究,探讨了廊道温度场、应力场分布规律及随时间的变化规律,为施工期廊道混凝土裂缝的控制提供理论依据。     

Modeling the Effects of Population Density on Prospect Theory-Based Travel Mode-Choice Equilibrium

In conventional transportation planning models, it was always assumed that the population density is given and fixed in the study areas. Therefore, the effects of population density on travel choice have not been explicitly incorporated into these existing models for long-term transportation planning. Meanwhile, travel choice models in previous studies are usually developed by using discrete choice theories or user equilibrium principle. Thus, many significant characteristics of travelers’ behaviors, such as risk preference and learning process over time, cannot be considered in these conventional models. This article proposes a convex prospect theory-based model to investigate the effects of population density on the travelers’ mode-choice behavior under an advanced transportation information system (ATIS) in a multimodal transportation corridor. It is shown that population density is closely co-related to the modal split results and dependent on the performance of the railway mode in the study corridor. The park-and-ride mode may not be suitable for areas with high population density. This article also investigates the travelers’ reference points on the generalized travel costs by modes. A numerical example is given to illustrate the properties of the proposed model together with some insightful findings.     

新建银川至西安铁路庆阳至西安段建设方案研究

为了确定银西线庆阳至西安段合理的建设方案,重点研究客货共线方案、客运专线方案和先接西平、部分缓建3个方案。综合考虑项目功能定位、通道走向、地形条件,结合路网运量,建设时序、路网分工、投资规模等多方面因素进行综合分析比较研究,研究结论为:银西线庆阳至西安段应按照客货共线方案一次建成。     

中巴经济走廊沿河台地特征及铁路选线要点

中巴经济走廊是我国"一带一路"倡议的先试区和重点项目区,拟建中巴铁路是其重要组成部分。走廊区域经历了多次强隆升作用和冰川作用,存在河流阶地、洪积扇、泥石流扇、冰碛台地等沿河台地。以中巴经济走廊Thakot至Khunjerab段为研究区段,归纳总结各类沿河台地的分布特征以及铁路选线的可利用性。结果表明:由于强隆升作用导致河流阶地拔河高度较大并出现了泥石流扇抬升后成为流通区的现象,Ⅰ级阶地和老扇面区成为可利用的地形;小冰期时冰川活动未企及的冰碛台地也可利用。研究结果有益于中巴铁路线路方案的优化。     

西部陆海新通道货运量预测研究

西部陆海新通道在区域协调发展格局中具有战略地位,对我国深化陆海双向开放、推进西部大开发形成新格局等具有重要意义.在分析西部陆海新通道总体规划及铁路网规划的基础上,结合西部陆海新通道功能定位,分析货运量影响因素,从区域间货运量、对外贸易货运量、分流沿江通道货运量3个方面进行运量预测.针对每部分货运量,在分析历年货运量的基...     

The corridor problem: Preliminary results on the no-toll equilibrium

Consider a traffic corridor that connects a continuum of residential locations to a point central business district, and that is subject to flow congestion. The population density function along the corridor is exogenous, and except for location vehicles are identical. All vehicles travel along the corridor from home to work in the morning rush hour, and have the same work start-time but may arrive early. The two components of costs are travel time costs and schedule delay (time early) costs. Determining equilibrium and optimum traffic flow patterns for this continuous model, and possible extensions, is termed “The Corridor Problem”. Equilibria must satisfy the trip-timing condition, that at each location no vehicle can experience a lower trip price by departing at a different time. This paper investigates the no-toll equilibrium of the basic Corridor Problem.     

瓜达尔港发展及布局研究

巴基斯坦瓜达尔港是中巴经济走廊的旗舰项目,也是中巴经济走廊西部唯一出海口,承担着未来走廊区域货物运输的重要任务。在对瓜达尔港现状及发展优势等分析的基础上,结合港口腹地的发展规划及产业发展趋势等的研究,提出瓜达尔港为中巴经济走廊出海口之一、巴基斯坦西部经济发展的支点、巴基斯坦重要港口、中亚五国出海口、南亚及毗邻中东的贸易中心的定位,同时结合城市布局做出"西湾发展旅游休闲功能,东湾发展城市服务及工业相关功能"的港口布局,并就今后港口开发提出建议。     

The corridor problem with discrete multiple bottlenecks

This paper presents a transparent approach to the analysis of dynamic user equilibrium and clarifies the properties of a departure-time choice equilibrium of a corridor problem where discrete multiple bottlenecks exist along a freeway. The basis of our approach is the transformation of the formulation of equilibrium conditions in a conventional “Eulerian coordinate system” into one in a “Lagrangian-like coordinate system.” This enables us to evaluate dynamic travel times easily, and to achieve a deep understanding of the mathematical structure of the problem, in particular, about the properties of the demand and supply (queuing) sub-models, relations with dynamic system optimal assignment, and differences between the morning and evening rush problems. Building on these foundations, we establish rigorous results on the existence and uniqueness of equilibria.     

A corridor-centric approach to planning electric vehicle charging infrastructure

The transition to electric vehicles (EV) faces two major barriers. On one hand, EV batteries are still expensive and limited by range, owing to the lack of technology breakthrough. On the other hand, the underdeveloped supporting infrastructure, particularly the lack of fast refueling facilities, makes EVs unsuitable for medium and long distance travel. The primary purpose of this study is to better understand these hurdles and to develop strategies to overcome them. To this end, a conceptual optimization model is proposed to analyze travel by EVs along a long corridor. The objective of the model is to select the battery size and charging capacity (in terms of both the charging power at each station and the number of stations needed along the corridor) to meet a given level of service in such a way that the total social cost is minimized. Two extensions of the base model are also considered. The first relaxes the assumption that the charging power at the stations is a continuous variable. The second variant considers battery swapping as an alternative to charging. Our analysis suggests that (1) the current paradigm of charging facility development that focuses on level 2 charging delivers poor level of service for long distance travel; (2) the level 3 charging method is necessary not only to achieve a reasonable level of service, but also to minimize the social cost; (3) investing on battery technology to reduce battery cost is likely to have larger impacts on reducing the charging cost; and (4) battery swapping promises high level of service, but it may not be socially optimal for a modest level of service, especially when the costs of constructing swapping and charging stations are close.