Governance for Sustainable Coastal Futures

The mobile nature of soft coasts means that coastal communities face uncertainty in their property values and peace of mind when the existing coastal defense is lowered or removed. The acceptance by the U.K. government that coastal realignment in areas of low population density and limited ecological value is unavoidable means that the current state of affairs, where coastal residents have broadly come to assume that they will be defended if they make enough fuss, cannot continue. The government is currently unwilling to confront this consternation and continues to refuse to pay compensation for lost property value. This is creating an outcry over loss of fairness of treatment. This dispute raises important questions of governance for coastal change. This participatory research project worked closely with English Nature, North Norfolk District Council, local residents associations, the Environment Agency, and the Department for Environment, Food and Rural Affairs. What emerged in the analysis were unresolved tensions between national strategic frameworks, emerging planning arrangements, changing economic assessments, and the desirability of delivering, through a number of public and voluntary agencies, local flexibility in participation and in coastal design. This article reports on the research process, the challenges for coastal governance, and the scope for creative partnerships between science, planning, policy delivery, and public acceptance.     

Extended gate operations at the ports of Los Angeles and Long Beach: a preliminary assessment

The paper examines the implementation of extended gate operations at the Los Angeles/Long Beach ports. The programme, known as PierPASS, assesses a Traffic Mitigation Fee (TMF) on eligible containers moved into and out of the ports during peak hours. The fees are intended to defray the costs of extended operations at the ports.

In this paper we focus on the implementation of the programme and its outcomes over a year of operation. We discuss the motivations and actions of key stakeholders and place our examination in the institutional framework of the goods movement supply chain. Our results are based primarily on a series of extended interviews with stakeholders, together with data provided by PierPASS and by three drayage trucker surveys. We find that the PierPASS programme was a response by terminal operators and steamship companies to growing political pressure. Given their market power within the supply chain, they were able to create a programme that protected their interests yet responded to political imperative. The PierPASS programme has been a success: the peak fee has shifted a significant share of cargo to evenings and weekends, as intended. Winners and losers of PierPASS reflect the larger structure of the international supply chain.     

The influence of built environment to the trends in commuting journeys in the Netherlands

In this paper we describe commuting trends in the Netherlands in the past decade and examine the influence of urban form and travel accessibility on commuting journeys over time on the basis of data from the Dutch National Travel Survey. Exploratory analysis is performed to identify changes in commuting participation, departure time, commuting time, commuting distance and the modal split. Regression analysis and choice models are used to examine the influence of the built environment on commuting parameters over time. The results indicate that urban form has consistently influenced the parameters of commuting journey in the Netherlands in the last 10 years. However, the trend of the influence is unique for each commuting model. Some influences have become less significant in the last decade and some have become stronger.

耦合式单轴转向架

介绍1种新型的径向设计方案——耦合式单轴转向架。该转向架在各种半径的曲线线路上具有非常理想的通过性能,而且在改善曲线通过性能的同时,可提高车辆的直线运行稳定性。通过试验确认了该转向架具有良好的动力学性能。     

Prediction of wheel wear in urban railway transport: comparison of existing models

One of the most important maintenance costs in tramway transport comes from wear of wheel profiles. In the highly competitive railway market, the prediction of wear is then a major concern of the constructors. In this article, we present and compare four models well adapted to tramway conditions, involving contacts on the rolling tread and on the flange with very different sliding and pressure conditions. Moreover, all models can be implemented from the natural outputs of the railway simulation packages classically used in industry for the dynamics design of the vehicles. The first one, proposed by Jendel, is based on the well-known Archard's wear model. Enblom continues Jendel's approach by taking into account the contribution of wheel deformation on the sliding velocity. The last two models, developed by Zobory, and Pearce and Sherratt, determine the wear from the energy dissipation in the contact area. The models are first compared on a theoretical basis and, for that purpose, are rewritten in a common form. Two cases are distinguished: mild wear as arising on the rolling tread and severe wear as arising on the flange. The models are also compared in the practical case of an urban transport vehicle running on circular tracks with different curve radii. Although the models show equivalent trends according to the theoretical study, important discrepancies appear between estimated wear depths. All models are actually dependent on experimental coefficients and it is likely that they were estimated in different conditions. On the other hand, a reasonable agreement can be found in some particular conditions. As an example, Zobory's, Enblom's and Jendel's models are very close to each other in severe wear conditions. This work shows that a general and reliable model could probably be developed from all positive aspects of the existing ones.     

A theoretical travel-time model for flexible-route buses

A theoretical model for estimating the expectation and variance of buses' running times under a flexibly-routed mode of service is proposed. The model is based on a probabilistic concept that adequately accommodates the usual randomness in the number and location of passengers served during successive vehicle trips. A few simplifications are embodied in the model but it can serve as a basis for a more refined model such as a computer simulation model that can be used in designing real bus systems.The physical setting assumed in the model is a rectangular grid road network where all houses face the side streets as in some suburban regions. Because it oversimplifies real-life situations, this assumption would need to be relaxed to make the model applicable to more general cases.Both the partially flexible-route service where some passengers are captive to fixed-route service and others are served at their doorsteps, and the fully flexible-route service where all passengers are served at their doorsteps, are studied. In each case, a very simple routing convention that can be conveniently executed by the bus drivers is assumed. The proposed travel time model confirms the intuitively correct phenomenon that when the concentration of passenger trip-ends is very high, the vehicle-route degenerates into a fixed-route in which the buses visit all possible loading points within the service area.