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.     

Great Britain adults’ opinions on cycling: Implications for policy

In its neglect of cycling, the transport policy history of Great Britain is typical of many car-dependent societies. Policy inertia with respect to sustainable travel may be driven by the assumptions that, firstly, most households have access to the use of a car and are keen to preserve the mobility advantages the current system offers them, and secondly that environmental and health considerations should be subjugated to economic priorities. Thus, in spite of warm words about cycling, pro-car policies tend to dominate.Set against this policy backdrop, and taking the stance that public opinion can influence policy change, this paper reports the results of two large scale surveys of opinions regarding the practice of cycling and its role within society, carried out amongst samples of adults representative of Great Britain, in 2010 and 2013. Results indicated broadly positive opinions relating to cycling as part of society, albeit with these measures dropping slightly between 2010 and 2013. Opinions of cycling were found to be significantly linked to voting intention with, broadly speaking, a gradient of decreasing positivity when moving from the political left to right. These results imply a possible link of ‘surface’ opinions of cycling being influenced by underlying ‘deep-seated’ beliefs and values. These results are discussed in terms of policy options for pro-cycling groups wishing to influence the debate. Options include decoupling cycling from underlying belief systems and presenting simply as a form of everyday transport; promoting cycling as a solution to multi-social issues across health, the environment and economic considerations such as lower congestion; the pros and cons of de-marketing car usage; and finally, changing underlying belief systems. It is concluded that pro-cycling advocates may be pleased with the broad support of cycling’s contribution to society, but they may need to seek alliances with other environmental or health groups in order to turn these good intentions into genuine policy change.     

基于共识度决策的军事物流配送中心选址研究

军事物流配送中心选址是其规划和运行的重要步骤,其选址问题是多目标群决策问题．在获取专家的权重矩阵和评估矩阵之后,建立了基于共识度水平的战时配送中心选址决策模型,通过计算为获取共识所需对权重向量做出修改的幅度,确定每个方案的共识程度,并给出一个算例说明这种决策方法的步骤．     

城市新区客运交通需求预测方法研究

城市客运交通需求预测是城市道路交通规划的基础。城市新区因缺乏现状交通调查资料、开发建设速度较快及其交通出行特征,传统客运交通需求预测方法已不再适用。在吸取国内城市道路交通规划实践经验的基础上,针对城市新区背景下道路交通规划的特点及传统客运交通需求预测方法的不足,以城市新区人口和土地利用规划为基础,提出一种面向城市新区的客运交通需求预测方法,可为我国城市新区交通预测提供借鉴。     

多联式氟泵机房空调在地铁设备用房应用的探讨

针对地铁车站设备用房通风空调系统普遍存在功能性、经济性以及运维便捷性等的问题,在系统分析现状与挑战的基础上,结合数据中心空调领域新技术——多联式氟泵机房空调的发展趋势,提出该技术在地铁车站设备用房的应用方案,并以我国北方某城市的标准地下车站为例,与传统方案进行综合技术经济对比分析。结果表明,多联式氟泵机房空调在提升房间控温效果、节约运行能耗、保障空气品质、匹配负荷特性、方便施工运维、降低控制难度等方面具有技术优势;该方案的初投资虽高于传统方案约70万元,但运行费用低于传统方案约22.7万元/年,静态投资回收期约为3.1年,具有良好的经济性。     

城市轨道交通对城市结构的影响因素分析

分析了两种城市结构即单中心同心圆与多中心轴线式的特点。从我国城市可持续发展的角度指出我国大城市理想的发展模式是多中心轴线式。从人口环境,土地等方面阐述了城市轨道交通在城市结构变迁中的重要诱导作用,最后从我国城市的现状指出发展轨道交通应注意的几个问题。     

高速列车隧道内等速交会对车辆动力学性能的影响

基于风压载荷空气动力学控制方程,利用计算流体力学软件FLUENT,分析高速列车在不同线间距隧道内,以不同速度级等速交会时的车体表面风压和受到的气动力;将隧道内交会时受到的气动力以时程荷载的形式施加到车辆动力学模型中,分析其对各项车辆动力学性能的影响规律,并进行安全性和平稳性指标分析。结果表明:列车在隧道内等速交会时,头车所受的气动阻力、升力、横向力最大;高速列车表面所受的风压极值与速度的2.2~2.3次方成正比,所受的气动阻力、升力、横向力与速度的1.8~2.4次方成正比;隧道内高速交会对车辆安全性指标影响不大,仅在交会瞬间产生较大的车体横向振动,当运行速度达到400km·h^-1时各项安全性、舒适性指标均满足限值要求。     

Transit technology investment and selection under urban population volatility: A real option perspective

This paper addresses transit technology investment issues under urban population volatility using a real option approach. Two important problems are investigated: which transit technology should be selected and when should it be introduced. A real option model is proposed to incorporate explicitly the effects of transit technology investment on urban spatial structure in terms of households’ residential location choices and housing market. The trigger population thresholds for investing in a transit technology project and for shifting from a transit technology to another are explored analytically. Comparative static analyses of the urban system and transit technology investment are also carried out. It was found that (i) transit technology investment can induce urban sprawl; (ii) ignoring the effects of transit technology investment on urban spatial equilibrium can lead to a late investment; and (iii) there is a significant difference in the trigger population thresholds for transit technology shift estimated by the net present value approach and the real option approach.     

Robust transit network design with stochastic demand considering development density

This paper analyzes the influence of urban development density on transit network design with stochastic demand by considering two types of services, rapid transit services, such as rail, and flexible services, such as dial-a-ride shuttles. Rapid transit services operate on fixed routes and dedicated lanes, and with fixed schedules, whereas dial-a-ride services can make use of the existing road network, hence are much more economical to implement. It is obvious that the urban development densities to financially sustain these two service types are different. This study integrates these two service networks into one multi-modal network and then determines the optimal combination of these two service types under user equilibrium (UE) flows for a given urban density. Then we investigate the minimum or critical urban density required to financially sustain the rapid transit line(s). The approach of robust optimization is used to address the stochastic demands as captured in a polyhedral uncertainty set, which is then reformulated by its dual problem and incorporated accordingly. The UE principle is represented by a set of variational inequality (VI) constraints. Eventually, the whole problem is linearized and formulated as a mixed-integer linear program. A cutting constraint algorithm is adopted to address the computational difficulty arising from the VI constraints. The paper studies the implications of three different population distribution patterns, two CBD locations, and produces the resultant sequences of adding more rapid transit services as the population density increases.