Shipping economics: where we are and looking ahead from an institutional economics perspective [1]

There have been significant changes in the nature of shipping services in recent years. These have been most notably in the liner segment, but other parts of the market have not remained static. Technology shifts have been responsible for some of the change, but there have also been developments in institutional structures and managerial approaches. The economic drivers behind the sector, however, remain relatively poorly understood, despite a copious literature on shipping. Managerial economics has tended to put emphasis on the emergence of more sophisticated logistics structures and the role of information to tighten the overall supply chain. Industrial economists have been concerned with technical change and in particular with its interaction with more liberal markets structures. Often tied with this has been interest in the underlying nature of shipping markets (e.g. competitive, monopolistic or contestable) and, depending on the outcome, whether there is price leadership, collusion, predatory behaviour or whatever. Much of this work has been aspatial, treating shipping as any other industry with distance between demand and supply ignored or incorporated in a very simplistic manner. Environmental economists have focused on matters of fuel efficiency and pollution. This paper takes a broad overview of shipping economics in the context of the larger institutional framework within which it operates. It seeks broader analysis within an institutional economics framework, but also highlights some of the problems of achieving this.     

Second international conference on new survey methods in transport Hungerford Hill,Australia 12–16 September 1983

The Second International Conference on New Survey Methods in Transport was held at Hungerford Hill, Australia in September 1983. The aims of the conference were to provide a focus for discussion of survey methodology and to establish bench‐marks with respect to the state of the art in various facets of transport surveys. The conference evolved around workshops in twelve key areas: sample design, survey needs for modelling, questionnaire design and piloting, perceptual studies, diary surveys, longitudinal studies, interactive survey methods, freight surveys, traffic surveys, total design concepts, response errors and data correction, and coding and computing.

A number of plenary keynote papers were also presented describing the state of the art in cross‐sectional, longitudinal and interactive survey methods. Emerging from the conference discussions, six key issues were prominent; the gap between the state of the art, as espoused by researchers, and the state of practice, as employed by practioners; the differences in results obtained when employing different survey methods to collect essentially the same data; the emerging use of the telephone for the conduct of interview travel surveys; the interaction between survey methods and demand modelling and the disparate levels of sophistication in the two areas; the role of microcomputers in the design, conduct and analysis of transport surveys; and the need for practitioners to engage in controlled experimentation, so that methodological advances may continue to be made in the field of transport surveys.     

社区步行通达性对独栋住宅房价的效益评估--美国德克萨斯州奥斯丁市空间特征分析

通过分析美国德克萨斯州奥斯丁市2010—2012年独栋住宅的销售价格,以街道智慧步行指数(Street Smart Walk Score)和人行道密度(Sidewalk Density)作为衡量指标,研究社区步行通达性对房价的影响。使用Cliff-Ord空间特征模型(即广义空间模型,General Spatial Model,或者SAC)控制空间自相关影响。结果表明：在依赖小汽车的社区通过增加设施可达性来提升步行通达性的举措并不能提高房价;增加人行道也只能最小限度地提高房价。投资社区便利设施和人行道对适宜步行社区的房价提升效果比依赖小汽车的社区显著。     

Lane changing patterns of bane and benefit: Observations of an uphill expressway

A mechanism is unveiled by which congestion forms on a 3-lane, uphill expressway segment, and causes reductions in output flow. Vehicular lane-changing (LC) is key to the mechanism, particularly LC induced by speed disturbances (SDs) that periodically arise in the expressway’s median and center lanes. Early in the rush, when flow was relatively low in the shoulder lane, drivers readily migrated toward that lane to escape the oncoming SDs. The shoulder lane thus acted as a ‘release valve’ for the high vehicular accumulations created by the SDs, such that forced vehicular decelerations were short-lived. The release valve failed only later in the rush, when flow increased in the shoulder lane in response to rising demand. LC induced by the SDs thereafter became disruptive: the decelerations they imposed spread laterally, and a persistent queue formed in all lanes. Long-run output flow dropped each day by 4-11% once the queue engulfed the base of the incline, and impeded vehicle ascent.Subtle details of this mechanism became visible by examining thousands of vehicle trajectories that were extracted from a series of eleven roadside video cameras. Though these trajectories were collected from only a single day, we suspect that the findings can be generalized to other days at the present site, and to other sites. This is because: (i) conspicuous features of the mechanism were repeatedly observed in loop detector data that were measured over many days at the site; (ii) these macroscopic features are consistent with observations previously made at other sites; and (iii) the more subtle details unveiled by the trajectories are compatible with a general theory of multi-lane traffic.     

Modeling stochastic perception error in the mean-excess traffic equilibrium model

In this paper, we extend the α-reliable mean-excess traffic equilibrium (METE) model of Chen and Zhou (Transportation Research Part B 44(4), 2010, 493-513) by explicitly modeling the stochastic perception errors within the travelers’ route choice decision processes. In the METE model, each traveler not only considers a travel time budget for ensuring on-time arrival at a confidence level α, but also accounts for the impact of encountering worse travel times in the (1 − α) quantile of the distribution tail. Furthermore, due to the imperfect knowledge of the travel time variability particularly in congested networks without advanced traveler information systems, the travelers’ route choice decisions are based on the perceived travel time distribution rather than the actual travel time distribution. In order to compute the perceived mean-excess travel time, an approximation method based on moment analysis is developed. It involves using the conditional moment generation function to derive the perceived link travel time, the Cornish-Fisher Asymptotic Expansion to estimate the perceived travel time budget, and the Acerbi and Tasche Approximation to estimate the perceived mean-excess travel time. The proposed stochastic mean-excess traffic equilibrium (SMETE) model is formulated as a variational inequality (VI) problem, and solved by a route-based solution algorithm with the use of the modified alternating direction method. Numerical examples are also provided to illustrate the application of the proposed SMETE model and solution method.     

The theory of second best in urban mass transit: Management in the public sector as a proforma exercise

This paper focuses on four issues. The first is the case of one-sided investments in mass transit in metropolitan areas of developing countries. It is pointed out that in many cases in which the conditions for optimum investment policies (Pareto's Optimum) are not maintained, excessive investments on mass transit, including large annual operating subsidies, usually lead to substantial sub-optimizations and waste of scarce financial resources. This problem is then reviewed under the light of the “Theory of Second Best” as articulated for all investment options within Welfare Economic Theory. The second issue examined is the matter of recently discovered important diseconomies of scale of large metro transit systems in developing and developed countries, and the need to retain production of transport services within small-scale production units that are well coordinated and controlled. The third issue discussed is the problem of mismanagement of most public sector transit companies and agencies. The notion that most such systems are simply administered, not managed, is being brought up and the requirements for proper management are amplified. Finally, the case of public vs. private ownership of mass transit is being discussed with a distinction between public policies of providing mass transit services and the actual production process of these services. Provision of services represents a public responsibility that belongs to the public sector. However, production of service is a techno-economic process that requires different talents and circumstances. The paper concludes with a strong suggestion for major reorientation of urban mass transit in the metro areas of developing countries towards more efficiency and higher productivity.     

The role of accident exposure in transport system safety evaluations II: Group exposure and induced exposure

Part I of this paper has argued that any meaningful evaluation of transport system safety must include a consideration of the exposure to accidents, and has demonstrated the use and limitations of several measures of exposure at intersections and along links of the network. To complement this treatment of site exposure, this part of the paper will describe the use of group exposure measures in the assessment of risks incurred by people within particular population groupings. The use of induced exposure measures is also briefly reviewed.     

交通方式可达性差距——衡量交通可持续发展的指数

交通因其消耗大量能源而在可持续发展中扮演着重要角色,为了规划交通可持续发展,有必要提出能够评估和衡量交通可持续发展的指数。利用可达性概念和地理信息系统提出交通方式可达性差距指数。该指数由人口数量、就业岗位数、商店数以及学校数等决定,根据公共交通方式和私人交通方式间可达性指数差异计算。就能源效率而言,公共交通方式比私人交通方式更能实现可持续。可达性差距指数越高意味着可持续能力越强。通过比较香港1991年和1996年的可达性差距指数,来检验交通发展的可持续性是否有所提升。最后,讨论了如何运用可达性差距指数来检验土地利用以及交通发展政策和方案,以便确定更可持续的政策和方案。     

欧洲绿色交通发展经验

首先探索了绿色交通涉及的因素,指出可持续交通层面下的政策目标。对实现这些目标可以采取的相关策略进行分析,包括新技术的应用以及交通政策的干预。基于欧洲经验,总结了交通政策的效果和作用,包括土地利用、基础设施、交通管理、运营措施、信息和宣传、费用等。最后,针对实施交通战略过程中存在的体制、可接受性、财政三方面的阻碍提出建议。