The relationship between transportation perceptions and behavior over time

The aim of this paper is to discuss cross-lagged panel analysis in terms of the causal inferences it generates about the relationship of beliefs about modes and mode choice behavior. Frequencies of use of the single-occupant automobile (SOA), bus and carpool, as well as beliefs about each of the modes, were collected from a sample of central business district commuters at two points in time. The belief variables for each mode were summed to form composite measures and were corrected for unreliability due to measurement error.Perceptions of each mode and the frequency of its use were analyzed for influences operating over time. A time interval was assumed to exist during which the variables causally operated on each other. It was assumed that the time necessary for an individual to change modes based on his perception was equivalent to the interval required for a person to alter perceptions based on his experience. The causal structure relating the two variables was also assumed to be stable over time. An additional assumption was required to distinguish between third variable effects, or spuriousness, and dual causation: if a third variable were to be causing the relationship, it would be operating at a relatively constant rate over time.A strong causal relationship was found to be operating between beliefs about SOA and bus and use of those modes over time. The relationship is mutually causative; beliefs determine behavior and behavior reinforces and changes perceptions. Analysis of the carpool data indicated that the causal structure had changed over time and could not be analyzed with this technique. In general, support is evidenced for an adaptation or learning process interpretation of the relationship between beliefs and mode choice behavior.     

Planning for implementation

Although the urban transportation planning process has evolved into the most sophisticated of all urban planning processes, the increasirig difficulty in implementing long-range transportation plans in urban areas today suggests basic questions concerning the process which deserve critical examination.Planning for implementation of urban transportation programs, particularly during periods of rapidly changing human values, requires a continuing re-evaluation of both technical and organizational strategies and their interrelationships.This paper raises some fundamental questions about the traditional activities and relationships that have characterized most urban transportation planning programs in the past. It also suggests a number of strategies, both technical and organizational, that may contribute to the implementation of plans and programs resulting from the transportation planning process.The first portion of this paper discusses the implications of not providing transportation services to match metropolitan growth. The experience of the Washington Metropolitan Area over the past decade is used to illustrate these implications.A discussion of organizational and institutional constraints upon the planning process follows. Then, the implications for the planning process are explored, and the scale of planning is reviewed as well as the need for monitoring the performance and impact of facilities.Next, the paper deals with the need to broaden the range of solutions to transportation problems, including consideration of economic and land development policies to reduce travel demand, as well as the provision of new facilities.Finally, techniques for involving decision-makers in the planning process are discussed. Examples of special project activities in the Washington area are used to illustrate these techniques and their value.     

Changing the timing of activities in resolving Scheduling Conflicts

Following the growing interest in the characterisation and modelling of activity scheduling and re-scheduling behaviour, this paper reports the results of a study on the resolution of activity scheduling conflicts. Using empirical data collected through an Internet survey, the modification of the timing of pre-planned activities to accommodate a new activity in the schedule was analysed. Schedule adjustment was studied using a parametric hazard model. The results indicate that the characteristics of the activities involved are the most important factors influencing the process of schedule change. Several correlations among schedule modifications were found. Harry Timmermans is a Professor at the Eindhoven University of Technology. He is also Director of the Urban Planning Group and the European Institute of Retailing and Services Studies. Tomás Ruiz is a Lecture and researcher at the Technical University of Valencia (Spain). Prior to his employment with the University, Dr. Ruiz was a consultant at Estudios, Proyectos y Planificación S.A.     

Speed management via in-car devices: effects,implications, perspectives

The objectives of this paper are to identify in-vehicle systems for speed management that have been or are being developed, and to suggest recommendations for the implementation of systems that will effectively influence driving speeds and thereby significantly increase safety. The best safety effect is expected from an "intelligent" gas pedal, more specifically the automatic speed limiter. However, in terms of user acceptance, this system is least liked, although, acceptance seems to improve after it has been tried out. Nonetheless, the final goal for implementation should be a mandatory speed limiter system, starting with voluntary usage supported with educational measures. A period of car producers' standardisation of ISA-systems should be followed by legislation prescribing that all new vehicles are to be fitted with the system. Finally, some questions regarding further research are outlined.     

Testing a Framework for the Efficiency Assessment of Road Safety Measures

Abstract

The objective of this research is to develop and test a framework for efficiency assessment of road safety measures and evaluate its use in decision‐making. An exhaustive review of standard methodologies and practices related to cost‐effectiveness and cost–benefit analyses is carried out for that purpose. Moreover, a number of case studies are performed, concerning the efficiency assessment of various road safety measures in different countries, covering different types of road safety measures (user‐, vehicle‐ or infrastructure‐oriented, policy or enforcement, etc.), ranging from national to local levels of implementation and including both ex ante and ex post evaluations. From the results conclusions are drawn on the efficiency of different road safety measures and the related determinants. Furthermore, the case studies reveal a number of methodology and data issues for which further research is required. The procedures and barriers involved in the use of efficiency assessment techniques at different levels of decision‐making are also highlighted by means of feedback received during and after the various case studies. On the basis of these results, a framework for the promotion, implementation and evaluation of efficiency assessment in road safety decision‐making is proposed. A particular set of recommendations is also presented regarding the treatment of barriers (fundamental, institutional or technical) within the efficiency assessment itself and the related decision‐making process.     

Why are maritime ports (still) urban,and why should policy-makers care?

Despite ongoing transformations in the maritime transportation industry and the rise of global supply chain systems, most of the world's important container ports remain urban. Ports continue to occupy urban spaces, are embedded in localized knowledge systems, draw on urban labour markets and infrastructure and are subject to local politics and policy concerns. We identify contemporary geographic theories which help us understand the often increasingly urban attachment of core economic activities despite globalization. We explore how these theories may apply to port studies, highlighting both how they have been used by maritime scholars to this point and also why further development and application are warranted. We argue that a central concern of these geographic theories is the articulation of place- and sector-specific processes operating at a variety of spatial scales. This is in contrast to most maritime studies which continue to be dominated by perspectives which emphasize the global logic of the transportation industry and the analysis of space in generalized and abstract terms. We conclude that a re-appreciation in maritime studies of urban economic processes, informed by geographical theory, will provide policy-makers and others with more understanding of why deep connections between ports and urban places still matter.     

双向与单向道路网络:哪一个更高效?

为了改善机动车的可达性并避免驾驶人迷失,城市政府和规划师开始将中心城区传统的单向道路网络转换成双向行驶。双向道路网络可提升经济活力水平和中心城区的宜居性,而单向道路网络可提高通行能力。指出使用出行服务能力指标来衡量道路网络效率更适宜,将单向行驶与双向行驶道路网络的出行服务能力进行对比,后者交叉口的处理包括左转专用车道、左转渠化和禁止左转三种方式。结果显示,与传统认知和设计手册相反,双向道路网络通常比单向道路网络更有效率。在出行距离较短的情况下,允许转向的双向道路网络比单向道路网络的出行服务能力更高;禁止左转的双向道路网络比单向道路网络造成的绕行更少。     

Simulation of longitudinal dynamics of a freight train operating through a car dumper

A heavy haul train and car dumper model was created to analyse train longitudinal dynamics during dumping. Influence of such factors as performance curve of draft gears, total free slack in couplers, operating mode of train positioner and braking of last two cars of train on the in-train forces was considered.     

城市交通控制的演变--政策与技术变更

在过去的一个世纪里,城市交通控制始终在演变,以适应日益复杂的政策目标和不断增长的交通需求。一个高效的交通控制系统可以带来很多收益,例如缓解拥堵、提高经济效益以及改善道路安全和空气质量。车辆检测和通信技术方面取得的显著进步为交通控制系统的调控能力带来了一系列阶段性变化：从早期（固定配时）信号控制发展到现代化的集成系统。多种类型的交通控制系统在全球不同地区建设完成,每种系统都有各自的优势和不足。首先通过对比分析目前占据领先地位的商用系统（以及一些较少为人所知的系统）,凸显交通控制系统的关键特征和差异,然后评估目前的交通控制系统是否能实现现代交通政策的职能和需求。最后,探讨了当前及未来的交通政策,以及未来10年交通控制发展的技术性蓝图,指出交通控制有望通过技术进步从有限数据时代迈入大数据时代。