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The third part of the state-of-the-art focuses on the future of road safety modeling and on conjectures concerning the evolution of national safety indicators. In the absence of econometric developments specific to road safety modeling, the research future must rely on pre-existing statistical procedures of econometrics applied to discrete/count and to aggregate data. In terms of contents, growing interest in the heterogeneity of road accident outcomes by category of victims could lead to treatments of this issue across research streams, say by top-down and bottom-up developments, but this speculation does not rest on extant adequate formulations of the issue of road user class and victim analysis. But understanding the time profile of aggregate national performance indicators is quite another matter. 相似文献
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港口活动和城市活动既可以相互促进也可以相互制约,陆域交通系统同时承载这两种活动,对港城的发展至关重要。基于国内外港城发展实例,对港城空间拓展模式进行研究,发现交通系统制约的问题在港城规模上升阶段普遍存在,得出关键影响要素:1)港城交通体系需求层次与交通分流系统的匹配; 2)交通系统与港城用地布局的协调; 3)港口规模与港城集疏运道路系统的匹配。本文结合案例进行定性和定量分析。 相似文献
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Sabyasachee Mishra Snehamay Khasnabis Sunder Lall Dhingra 《Research in Transportation Economics》2013
Traditional economic analysis techniques used in the assessment of Public Private Partnership (PPP) projects are based upon the assumption that future cash flows are fully deterministic in nature and are not designed to account for risks involved in the assessment of future returns. In reality, many of these infrastructure projects are associated with significant risks stemming from the lack of knowledge about future cost and benefit streams. The fundamental premise of the PPP concept is to efficiently allocate risks between the public and the private partner. The return based on deterministic analysis may not depict a true picture of future economic outcomes of a PPP project for the multiple agencies involved. This deficiency underscores the importance of risk-based economic analysis for such projects. In this paper, the authors present the concept of Value-at-Risk (VaR) as a measure of effectiveness (MOE) to assess the risk share for the public and private entity in a PPP project. Bootstrap simulation is used to generate the risk profile savings in vehicle operating cost, and in travel time resulting from demand-responsive traffic. The VaR for Internal Rate of Return (IRR) is determined for public and private entity. The methodology is applied to a case study involving such a joint venture in India, the Mumbai Pune Expressway/National Highway 4 (MPEW/NH4), and fiscal implications from the perspective of the public and the private entities are examined. A comparison between deterministic and risk based economic analysis for MPEW/NH4 is presented. Risk analysis provides insightful results on the economic and financial implications from each participant's viewpoint. 相似文献
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收费公路类似自然生命,其成长和发展必然为一个具有若干阶段的连续过程。基于生命周期理论,对我国收费公路体系生命周期进行了探讨和分析。结果表明,2000年以后,我国收费公路进入成熟期;在2030年达到峰值后,收费公路在总量上开始缩减,进入衰退期,新的发展趋势也将逐渐体现。 相似文献
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The Belt and Road initiative is a novel exploration of China towards strategic collaboration with Eurasia countries to an extent of a larger scale with higher and deeper level of cooperation. To meet the growing global demand of transportation, increasing numbers of liner shipping companies collaborate and form alliances to share vessel capacity and reduce capital costs. Effective liner shipping vessel sharing is essential for the Belt and Road initiative in terms of building efficient maritime transport networks. In promoting environmental development, shipping companies are required to attain higher environmental standards. However, limited literature relates vessel sharing to environmental performance. This paper studies the impacts of liner vessel sharing from the economic and environmental perspectives. Two container allocation models are developed for the two scenarios: with and without vessel sharing. The carbon emissions in transportation are calculated under both scenarios. Numerical studies are carried out using services along the China-Indochina Peninsula Economic (CIPE) Corridor. Liner shipping companies could benefit from vessel sharing in terms of significant profit improvement. Vessel sharing could also benefit the environment by reducing the CO2 emissions dramatically. 相似文献
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S. Velmurugan S. Padma E. Madhu S. Anuradha S. Gangopadhyay 《Research in Transportation Economics》2013
In this study, an attempt has been made to develop Multinomial Logit (MNL) model by analysing the drunken and non drunken drivers involved in road crashes on Indian highways. Multinomial Logit model has been deployed to assess the influence of various parameters like vehicular, environment and geometric factors on the set of drivers who were found to be drunk at the time of getting involved in the road crash and those who were not under the influence of alcohol at the time of meeting with the road crash. The total economic cost of road crashes in the case of non-drunk driver road crash is Rs. 1046.27 million whereas in the case of drunk driver road crashes it is estimated to be Rs. 204.50 million. Further, it can be observed that economic cost of drunk driver road crashes is varying from 13 to 19 % across different types of road crashes. 相似文献
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Synergies between Adjacent Beach-Nourishing Communities in a Morpho-Economic Coupled Coastline Model
Beach “nourishment” consists of placing sand on an eroding beach. The widened beach provides increased storm protection to adjacent structures and improved recreational benefits, but is most often transient, requiring on-going, repeated nourishment episodes. Numerical models of beach nourishment typically address such questions as how long a widened beach will last; economic models compare the benefits and costs of preserving a stretch of beach without regard to its geomorphic evolution. Neither have addressed the physical nor economic interactions between adjacent nourishing communities. Here, we couple a numerical model of coastline evolution and a cost-benefit model of beach nourishment, allowing adjacent communities to make dynamic nourishment decisions. Beach nourishment benefits adjacent communities both “updrift” and “downdrift.” The total amount of money spent on nourishment activities can decrease by as much as 25% when adjacent communities both conduct on-going nourishment projects, as opposed to the case where each community nourishes in isolation. 相似文献
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David Simmonds 《Research in Transportation Economics》2011,31(1):2-11
In discussion of the modelling methods that can be used to assess the impacts of transport change on regional and local economies, “land-use/transport interaction (LUTI) models” are often referred to as if all such models were examples of a single, homogeneous commodity. The first and major purpose of this paper is to correct this impression by comparing and contrasting some key features of the main models or modelling packages in the LUTI tradition, particularly those which are generally recognized as constituting the current “state-of-the-art”, or at least the “state of practice”. One particular point within the comparison will be the differing use which is made (or not made) of spatial input-output models in the different approaches.The second purpose of the paper is (more briefly) to compare LUTI modelling with alternative approaches and in particular with spatial computable general equilibrium (SGCE) modelling. One of the common features to emerge from the preceding comparison is that LUTI modelling has been mainly concerned with predicting the location of fixed totals of jobs and of households under different transport scenarios. This is a general feature, even though in some cases these totals are directly fixed by the user whilst in other cases they are the results of long chains of calculations that are insensitive to transport scenarios; in a few cases, the total levels of economic activity are variable according to accessibility-related variables. In contrast, the use of SCGE modelling in testing the impact of transport proposals is very much concerned with the consequences for the total size of the economy in question, usually with a less detailed concern for the spatial distribution of impacts. This comparison leads to a discussion of whether LUTI modelling and SCGE modelling are mutually exclusive or whether some form of synthesis or integration between the two may be theoretically appropriate and/or practically desirable. The requirements of project appraisal - i.e., the assessment of benefits - are also considered. 相似文献
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Ourania Tzoraki Isavela N. Monioudi Adonis F. Velegrakis Nicolaos Moutafis Gerasimos Pavlogeorgatos Dimitra Kitsiou 《Coastal management》2018,46(2):78-102
This contribution addresses the need for a simple model for managers to employ when planning strategies for the management of touristic beaches under sea level rise. A methodological framework was developed and tested in two Aegean archipelago islands (Lesvos and Rhodes, Greece). The scheme can represent the status of touristic island beaches, based on easily obtained variables/indicators and projections of beach erosion/retreat under different scenarios of mean sea level rise (MSLR) and extreme events. Information on beach geomorphological characteristics, environmental setting, water quality, management, and services (such as those used in the “Blue Flag” classification) was collated/collected and beach erosion/retreat due to CV & C was estimated through suitable ensembles of cross-shore (1-D) morphodynamic models. A Strength-Weaknesses-Opportunities-Threats (SWOT) framework was employed to assist in the selection of indicators and multicriteria analysis used to optimize indicator weights and rank beaches according to their sustainability under sea level rise. Implementation of the framework at the two islands has shown that: the majority of Lesvos and Rhodes beaches (82% of a total of 217 beaches and 58% of a total of 97 beaches, respectively) can be classified as beaches with no, or minimal, human interference, suggesting that under environmentally sound coastal management further touristic development might be afforded; there could be very significant effects of the sea level rise on the carrying and buffering capacities of the most developed (“Blue Flag”) beaches, with some expected even under conservative projections to be completely eroded by 2100, unless technical adaptation measures are taken; and using the proposed framework, touristic beaches can be rapidly ranked in terms of their resilience to sea level rise and their development potential, allowing prioritization of effective management responses. 相似文献
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移动对象数据库对大量移动对象的位置信息进行管理,能够支持传统数据库不能进行的时空查询,考虑到大多数移动对象的运动都固定在已知的路线当中,基于公路网的移动对象数据模型通过对公路网拓扑图的数字化转换,能够对移动对象进行有效的管理,采用实时平均法反映每条线路的动态运行情况,对移动对象未来位置进行精确预测。 相似文献
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合理规划港区闸口通道数量和道路宽度是保证整个港区集疏运顺畅的关键因素。首先对码头闸口系统的作业特点和道路通行能力进行研究,定性分析并给出了闸口通道数量和道路通行能力相关参数的理论计算公式。然后利用计算机仿真技术,结合离散事件动态理论、排队论及交通流理论,建立了港区码头闸口通道数量及道路宽度仿真复合模型,并针对实际案例进行仿真试验研究。研究方法对提高港区规划设计水平有一定的参考意义。 相似文献
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海底光缆的稳定性日益受到关注,而海底光缆路由调查的质量将直接影响系统日后在施工交付和使用维护时的安全。通过对目前海底光缆路由调查作业及其主要作业设备的调查分析,有利于对未来该专业的发展方向进行规划。 相似文献
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佛山、珠海、中山等珠三角西部地区的集装箱生成量分别通过公路或水路中转到香港、南沙港区和深圳港,然后海运至欧洲、美国、加拿大和日本。通过对集装箱综合运输成本费用的调研分析,论证南沙港区对珠三角西部地区的近远洋集装箱箱源具有强大的吸引力。 相似文献
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在沥青路面施工中,常因集料吸水率超标而需另选其它料源,造成工程工期延长,成本增加。文中就该问题进行了理论和试验研究,得出了采用坚固性等指标综合判断吸水率超标集料可用性的方法,分析了采用这种集料的适用条件和施工中的质量控制重点,并在实际工程中得到应用和验证。 相似文献