A model to assess cost and fuel savings from ride sharing

A model based on geometric probability concepts is developed to assess the performance of carpooling and vanpooling strategies. Fuel consumption and operating cost issues are treated in the paper, and the model can be extended to treat travel time and air quality issues also. It is shown that simple calculations of the fuel saved through carpool programs can overstate the savings by a factor of two. The operating costs of vanpools and carpools are also compared.     

作为竞争因素的现代化动车组--以市郊铁路客运为例

铁路改革的核心目的之一,是在改善市郊铁路客运(SPNV)经济性的同时增加铁路对旅客的吸引力.决策者希望通过已知的乃至未知的竞争来实现这一点.德国铁路公司(DB AG)自成立后对这种新形势的反应是,对其机车车辆实施了较大范围的现代化改造和空前的采购计划.文章以城市高速铁路和区间铁路动车组为例,扼要介绍了近年来新购车辆以及新框架条件的影响.     

Some promising innovations in taxicab operations

Several shared-ride passenger transportation services which could be offered by taxicabs are currently prohibited in U.S. cities by state or local regulations. Although relaxation of these regulations has been advocated on numerous occasions, little regulatory change has occurred to date. Moreover, the taxicab industry has rarely been considered as a potential provider for publicly subsidized transportation services. This paper discusses several promising innovations in taxicab service provisions and subsidy mechanisms which have been implemented or proposed recently in U.S. cities. The paper argues for more well-designed experimentation with such innovations as a means of stimulating greater interest on the part of planners, policy-makers, regulators, and public transportation operators in broadening the role of taxicabs in urban transportation.     

The role of US ocean Ports in promoting an efficient ocean transportation system

This paper investigates wheather the actions of US ocean ports (since the passage of the Shipping Act of 1984) are supportive of the promotion of an efficient transportation system for US ocean commerce. In the short run, US ocean ports have generally been supportive of this efficiency goal;competiton among US ocean ports has has increased as is evident by the significant reduction that has occurred in port natural hinterlands. In the long run, port sunk costs, consolidations and cooperative activities, and long-term leases with ocean carriers are likely to be non-supportive of the efficiency goal.     

INTERFERON γ－INDEPENDENT EFFECTS OF INTERLEUKIN 12 ADMINISTERED DURING ACUTE OR ESTABLISHED INFECTION DUE TO LEISHMANIAMAJOR

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Optimal containership size

The cost per container movement incurred by a containership per voyage leg on a given route is minimized under various scenarios. The principal conclusions reached from a comparative analysis of the optimal containership sizes are: (1) for a route of a given distance and the same time in port per port call, optimal containership size declines as the number of port calls increase, (2) for a route of a given distance and the same number of port calls, optimal containership size declines as the time in port increases and (3) for the same number of port calls and the same time in port per port call, optimal containership size increases as the distance of the route increases. Rationale for these conclusions are presented.