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相信自己是一只雄鹰 一个人在高山之巅的鹰巢里抓到一只幼鹰,他把幼鹰带回家养在鸡笼里.这只幼鹰和鸡一起啄食、嬉闹和休息.它以为自己是一只鸡.  相似文献   

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This paper describes the development of a mode choice model for the journey to work with special emphasis on the propensity to cycle. The model combines Revealed Preference (RP) and Stated Preference (SP) data to form a very large and comprehensive model. RP data from the National Travel Survey was combined with a specially commissioned RP survey. A number of SP surveys were also undertaken to examine the effects of different types of en-route and trip end cycle facilities and financial measures to encourage cycling.The development of the model is described in detail. The model was used to forecast trends in urban commuting shares over time and to predict the impacts of different measures to encourage cycling. Of the en-route cycle facilities, a completely segregated cycleway was forecast to have the greatest impact, but even the unfeasible scenario of universal provision of such facilities would only result in a 55% increase in cycling and a slight reduction in car commuting. Payments for cycling to work were found to be highly effective with a £2 daily payment almost doubling the level of cycling. The most effective policy would combine improvements in en-route facilities, a daily payment to cycle to work and comprehensive trip end facilities and this would also have a significant impact on car commuting.  相似文献   

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《Transportation》1997,24(4):435-435
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根据输油工况和管线沿途的地质、土壤等状况,广泛采用管材多极变壁厚进行管线敷设,管线敷设还尽可能采用弹性敷设和冷弯弯管敷设,以便减少固定墩的数量。为保证焊接质量和管材强度,在管线上允许加装30°、45°、60°曲率半径大于5DN的3种热煨弯头与冷弯管(曲率半径=40DN)相配合,以适应管线走向所需要的转角。文中分析了3种敷设,选出最佳的敷设方案以降低成本。  相似文献   

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This paper analyses the Nationwide Personal Transportation Study (NPTS) surveys of 1977 and 1983–1984 that reveal a remarkable increase in nonwork travel. This growth occurred among all city size classes but was stronger for suburban residents. Also interesting is that the rate of increase in nonwork trips was higher in the peaks (especially in the morning peak) than in the off-peak period. Some, but not all, of these trips may be price-elastic and might be diverted by congestion pricing strategies. The nonwork trip growth is concentrated in the “family and personal” and the “social and recreational” categories. Although higher-income households make more trips than low-income households, the increase in nonwork travel is common to all income groups. The growth in nonwork travel does not appear to be closely associated with the growth in female employment or trips related to the children of working women. The most convincing explanation of the growth in nonwork travel is that the trip cost savings (less time and distance) experienced because of more efficient spatial settlement patterns have provided an incentive to undertake more trips. Another implication is that urban economic models and urban transport policies have overemphasized the journey to work, especially to the central business district (CBD).  相似文献   

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近年来,铁路客运”夕发朝至”、“朝发夕至”、“直达特快”及旅游专列等品牌列车的不断推出.城际列车的开通.使具有传统优势的长途、中短途客运的道路运输企业经营压力相应加大。旅客出行也开始有越来越多的选择机会.市场竞争不再是单一的价格与技术竞争.  相似文献   

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叙述了如何利用计算机软件实现化工管道支架材料的自动统计和材料表的自动输出,以提高管架设计的效率。  相似文献   

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偶尔翻翻报纸,看到不少各地有关去年治超成绩的通报,大凡是检查了多少超载车辆,卸载了多少吨超载货物,罚款累计多少元,超载率下降了多少.  相似文献   

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走合期合理使用 首先,购进新车后,一定要根据新车走合期的特点来合理使用.新车走合期有什么特点呢?第一,机件磨损快.汽车出厂前虽然按规定进行了磨合处理,但机件表面仍然较粗糙,加之新零配件间有较多的金属粒脱落,使磨损加剧.第二,故障多.  相似文献   

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Trip chaining as a barrier to the propensity to use public transport   总被引:1,自引:0,他引:1  
Hensher  David A.  Reyes  April J. 《Transportation》2000,27(4):341-361
Trip chaining is a growing phenomenon in travel and activity behaviour. Individuals increasingly seek out opportunities to minimise the amount of travel required as part of activity fulfilment, given the competing demands on time budgets and their valuation of travel time savings. This search for ways of fulfilling (more) activities with less travel input has produced a number of responses, one of which is trip chaining. A particularly important policy implication of trip chaining is the potential barrier it creates in attracting car users to switch to public transport. This paper seeks to improve our understanding of trip chaining as a barrier to public transport use. A series of discrete choice models are estimated to identify the role that socio-economic and demographic characteristics of households have on the propensity to undertake trip chains of varying degrees of simplicity/complexity that involve use of the car or public transport with an embedded commuting or non-commuting primary purpose. Multinomial logit, nested logit and random parameter logit models are developed and contrasted to establish the gains in relaxing the strict conditions of the multinomial logit model.  相似文献   

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Transit vehicles stopping to load/unload passengers on-line at a signalized intersection can obstruct the flow of other vehicles. The TRANSYT model ignores the delay to other traffic caused by this loading/unloading process. This can cause TRANSYT to use incorrect flow profiles, resulting in signal timings that cater to these profiles rather than the actual ones. This paper describes a new model for representing near-side transit stops in lanes shared by public transit and private vehicles, and its implementation into the TRANSYT-7F program. The results of an initial application of the proposed model are also described. The proposed model, which is a deterministic simulation model, is able to represent the effect of near-side transit stops on the other traffic; this representation covers both total and partial blockage of the approaches during the transit loading. The procedure has been incorporated into the TRANSYT-7F program. This allows appropriate representation of the adverse effects of transit loading on-line during a green phase. It thus encourages the TRANSYT optimizer to push transit loading to the red phases.  相似文献   

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This paper attempts to explore the possibility of solving the traffic assignment problem with elastic demands by way of its dual problem. It is shown that the dual problem can be formulated as a nonsmooth convex optimization problem of which the objective function values and subgradients are conveniently calculated by solving shortest path problems associated with the transportation network. A subgradient algorithm to solve the dual problem is presented and limited computational experience is reported. The computational results are encouraging enough to demonstrate the effectiveness of the proposed approach.  相似文献   

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In this paper we employ survival analysis methods to analyse the impact of driving patterns on distance travelled before a first claim is made by young drivers underwriting a pay-as-you-drive insurance scheme. An empirical application is presented in which we analyse real data collected by a GPS system from a leading Spanish insurer. We show that men have riskier driving patterns than women and, moreover, that there are gender differences in the impact driving patterns have on the risk of being involved in an accident. The implications of these results are discussed in terms of the ‘no-gender’ discrimination regulation.  相似文献   

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Zambia has attempted to reduce her excessive transport dependency on her traditional transport routes via South Africa and the former Portugese colonies. The costly construction of the Tanzania‐Zambia Railway (TAZARA) was part of this diversification strategy. This article examines the nature, extent and direction of Zambian traffic, including its historical evolution. It explores further the place of TAZARA among the various routes to Mozambican, Angolan and South African ports, and the ensuing actual and potential competition. Future traffic patterns will be influenced not only by the direct and service‐oriented costs of the different lines, but also by the region's volatile and uncertain political climate.  相似文献   

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隧道渗漏往往带来结构损坏、设备腐蚀、影响外观和危害运营安全,甚至造成地面建筑物的不均匀沉降,因此保证明挖隧道的防水效果非常重要。文章从施工实践中总结出了保证明挖隧道防水效果应注意的几个问题,对类似工程具有借鉴作用。  相似文献   

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Using a range of nonparametric methods, the paper examines the specification of a model to evaluate the willingness-to-pay (WTP) for travel time changes from binomial choice data from a simple time–cost trading experiment. The analysis favours a model with random WTP as the only source of randomness over a model with fixed WTP which is linear in time and cost and has an additive random error term. Results further indicate that the distribution of log WTP can be described as a sum of a linear index fixing the location of the log WTP distribution and an independent random variable representing unobserved heterogeneity. This formulation is useful for parametric modelling. The index indicates that the WTP varies systematically with income and other individual characteristics. The WTP varies also with the time difference presented in the experiment which is in contradiction of standard utility theory.  相似文献   

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