Generation of logistics networks in freight transportation models

This article analyzes the concept of logistics networks in the context of behavioral freight transport modeling. Starting from the basic definition of networks, the different perceptions of networks in transportation science and logistics are worked out. The micro?Cmacro gap, as a main challenge in freight transport modeling, is explained by the existence of logistics networks on a meso level. A taxonomy of modeling methods dealing with logistics networks is defined, based on two characteristics: the changeability of networks within models (fixed, partially variable and variable networks) and the form of cost functions mapped (economies of scale, constant average cost, and diseconomies of scale). For each category, different possible modeling methods and their application in existing freight transport models are discussed. A special focus is placed on methodologies and models that map variable networks.     

长大桥梁工程的先进节段预制技术及其应用

桥梁,作为基础设施的核心部分之一,在高速铁路、高速公路、城市地铁或轻轨国家交通网络的发展中扮演了重要角色.在中国高速铁路、高速公路或客运专线交通基础设计建设中,桥梁的设计和施工经常成为决定性因素.在过去的几十年中,桥梁设计者和建造者把节段预制技术(例如,小节段混凝土精确预制、大尺寸混凝土预制和大尺度钢结构预制)推进到了一个新高度,为交通领域的决策者提供了坚实的技术平台.本文简要介绍了这种先进的预制节段技术及其在世界范围内的著名应用范例.     

大型体育赛事交通总体规划框架及要点

清晰、简洁且全面的大型体育赛事交通总体规划是赛事成功举办强有力的保障.它整合现有和未来可能使用的城市交通系统、交通网络系统、交通运营系统、相关机构及各客户群体,并在赛事交通与城市交通之间寻求平衡点.以2014年索契冬奥会和2018年平昌冬奥会的奥运交通总体规划为案例,总结赛事交通总体规划的框架,剖析规划内容和要点,识别...     

Costs and benefits of a bicycle helmet law for Germany

This study presents a cost–benefit analysis of a law requiring cyclists to wear a helmet when riding a bicycle in Germany. The cost benefit-analysis takes into account the benefit of increased security when cyclists wear a helmet or use a transport mode that is less risky than cycling. The analysis also considers the cost of purchasing helmets, reduced fitness when cycling is replaced by a motorized transport mode, the discomfort of wearing helmets and environmental externalities. The benefits of a helmet law are estimated at about 0.7 of the costs. A bicycle helmet law for Germany is found to be a waste of resources.