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1.
Summary High-frequency train-track interaction and mechanisms of wheel/rail wear that is non-uniform in magnitude around/along the running surface are surveyed. Causes, consequences and suggested remedies to relieve the problems are discussed for three types of irregular wheel/rail wear: (1) short-pitch rail corrugation on tangent tracks and large radius curves, (2) wheel corrugation as caused by tread braking, and (3) wheel polygonalisation. The state-of-the-art in modelling of dynamic train-track interaction in conjunction with prediction of irregular wear is reviewed.  相似文献   
2.
International shipping is a significant contributor to global greenhouse gas (GHG) emissions, and is under mounting pressure to contribute to overall GHG emission reductions. There is an ongoing debate regarding how much the sector could be expected to reduce emissions and how the reduction could be achieved. This paper details a methodology for assessing the cost-effectiveness of technical and operational measures for reducing CO2 emissions from shipping, through the development of an evaluation parameter called the Cost of Averting a Tonne of CO2-eq Heating, CATCH, and decision criterion, against which the evaluation parameter should be evaluated. The methodology is in line with the Intergovernmental Panel on Climate Change (IPCC) and with regulatory work on safety and environmental protection issues at the International Maritime Organization (IMO).

The results of this study suggest that CATCH <50 $/tonne of CO2-eq should be used as a decision criterion for investment in emission reduction measures for shipping. In total, 13 specific measures for reducing CO2 emissions have been analysed for two selected case ships to illustrate the methodology. Results from this work shows that several measures are cost effective according to the proposed criterion. The results suggest that cost effective reductions for the fleet may well be in the order of 30% for technical measures, and above 50% when including speed reductions. The results of this study show that the cost effectiveness approach for the regulation of shipping emissions is viable and should be pursued in the ongoing regulatory process.  相似文献   
3.
The aim of this article is to discuss theoretically and to study empirically how Norwegian drivers' willingness to pay (WP) for not losing their driving licence vary with their personal characteristics. The theoretical discussion and empirical results are based on standard microeconomic theory and contingent valuation, respectively. The WP values increase concavely with the length of the suspension period of the driving licence and differ greatly between drivers. They increase significantly with a driver's income, dependence on the car at work and driving experience. Moreover, male drivers, young drivers and drivers living in rural areas have higher WP values than their counterparts. Consequently, driving licence suspension will deter drivers to different extents. The relative impacts of the above explanatory variables on the WPs are, broadly speaking, independent of the length of the suspension period.  相似文献   
4.
5.
Road pricing is a policy measure recommended by transport planners and economists, but considered infeasible by many due to political and public resistance. The Trondheim experience demonstrates how a crude road pricing scheme can be implemented in a moderately congested city while paying heed to democratic decision-making. Fair and democratic procedure requires that the planning include a responsive citizen participation process, that the political parties feed all the viewpoints of the main interest groups into the City Council decision-making, and that the public debate be open and admit all groups mass media coverage. Lessons from the Trondheim toll ring case are offered concerning (1) interests and coalition building, (2) pro and con arguments, (3) the viability of democratic procedure, (4) frequent forms of manipulation, and (5) main issues of design and revenue spending.  相似文献   
6.
Reciprocity relations are valid also for dynamic problems (Fung, reference [1]). In this paper, the reciprocity relation is first used to determine the response of a simply supported beam subjected lo an arbitrarily time-varying force moving with constant speed. Then the reciprocity relation is used to determine the response of a beam-like structure (a beam on mass-spring supports, a model of a railroad) subjected to a moving constant force. Numerical solutions, including also a pair of moving forces, are given.  相似文献   
7.
International shipping is a significant contributor to Global Greenhouse Gas (GHG) emissions, responsible for approximately 3% of global CO2 emissions. The International Maritime Organization is currently working to establish GHG regulations for international shipping and a cost effectiveness approach has been suggested to determine the required emission reductions from shipping. To achieve emission reductions in a cost effective manner, this study has assessed the cost and reduction potential for present and future abatement measures based on new and unpublished data. The model used captures the world fleet up to 2030, and the analysis includes 25 separate measures. A new integrated modelling approach has been used combining fleet projections with activity-based CO2 emission modelling and projected development of measures for CO2 emission reduction. The world fleet projections up to 2030 are constructed using a fleet growth model that takes into account assumed ship type specific scrapping and new building rates. A baseline trajectory for CO2 emission is then established. The reduction potential from the baseline trajectory and the associated marginal cost levels are calculated for 25 different emission reduction measures. The results are given as marginal abatement cost curves, and as future cost scenarios for reduction of world fleet CO2 emissions. The results show that a scenario in which CO2 emissions are reduced by 33% from baseline in 2030 is achievable at a marginal cost of USD 0 per tonne reduced. At this cost level, emission in 2010 can be reduced by 19% and by 24% in 2020. A scenario with 49% reduction from baseline in 2030 can be achieved at a marginal cost of USD 100 per tonne (27% in 2010 and 35% in 2020). Furthermore, it is evident that further increasing the cost level beyond USD 100 per tonne yield very little in terms of further emission reduction. The results also indicate that stabilising fleet emissions at current levels is obtainable at moderate costs, compensating for fleet growth up to 2030. However, significant reductions beyond current levels seem difficult to achieve. Marginal abatement costs for the major ship types are also calculated, and the results are shown to be relatively homogenous for all major ship types. The presented data and methodology could be very useful for assisting the industry and policymakers in selecting cost effective solutions for reducing GHG emissions from the world fleet.  相似文献   
8.
Successful public transport service contracts can be judged against procedural and outcome criteria, located within an integrated strategic, tactical and operational level framework for planning and delivery. Clear goal setting at the strategic level sets the basis for supportive tactical system planning and for service delivery that meets goals. The workshop considers relevant success criteria and key matters that need to be resolved for their achievement. Market growth potential and the governmental attitude to supporting service growth are important issues shaping the contractual environment. The growing interest in negotiated performance-based contracts and the role of trust between the operator and the authority are also matters for particular attention.  相似文献   
9.
This paper discusses and compares some ride comfort criteria which may be suitable for randomly vibrating vehicles. The criteria consider single-figure measures based on response mean square spectral densities for plane linear combined vehicle-passenger models. Eight different measures divided into three groups are studied. The two vehicle suspension damper stiffnesses are numerically optimized with respect to the eight measures of ride comfort. The results are compared and discussed. Two optimizations with respect to five vehicle parameters are also reported.  相似文献   
10.
Langmyhr  Tore 《Transportation》2001,28(2):157-178
Investment packages, involving several modes, emerge as a widely used element in urban transport policies. Package policies entail some specific possibilities and traps in the planning and decision-making processes. To assess these properties, the concepts of instrumental and communicative rationality are applied. These rationality concepts serve to structure the pro and con arguments concerning four crucial considerations in package planning: The use of formal impact assessment methods, the overall size and changeability of the investment packages, the share of road vs green modes investments, and the sequence of implementation. These issues are investigated by drawing on experience from transport investment packages in six Norwegian cities.  相似文献   
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