Changes in transport risk perception in urban populations in Norway from 2004 to 2013

Urban populations transport risk perception is interesting because it is associated with travel mode choices and use. This study investigates changes in transport-related risk constructs in the urban population in Norway in 2004 and 2013, and describes whether people perceive private or public to be associated with the highest risk. The results are based on self-completion questionnaire surveys conducted in two independent representative samples living in the same urban areas in 2004 (n?=?592) and 2013 (n?=?1035). Overall, the respondents perceived the risk as lower in 2013 than in 2004. For both time periods, people consistently assessed the risk constructs related to private motorized transportation as higher than corresponding risk in public transportation. The findings suggest that while transportation risk perception in urban populations may change over time, the pattern that private motorized transportation is associated with a higher perceived risk than public transportation remains stable.     

Mode selection of tractor-and-semitrailer swap transport for ro-ro shipping under land-sea combined transportation

ABSTRACT

Combining ro-ro shipping and tractor-and-semitrailer swap transport under land-sea combined transportation can reduce operating costs and improve the safety of maritime transport. In addition, selection of the tractor-and-semitrailer swap mode (i.e., the ship-swap mode and port-swap mode) is a critical factor that affects the efficiency and cost of ro-ro ship loading/unloading. Considering inland pickup/delivery and ship loading/unloading, this paper develops a model that determines the mode of tractor-and-semitrailer swap transport with the objective of minimizing the total cost. This study also considers constraints such as empty semitrailer exchange and multiple time windows associated with customer receiving/delivery locations and the ro-ro ship. A hybrid simulated annealing (SA) is applied to solve the problem. By analysing numerical examples, the results show that the port-swap mode is more suitable than the ship-swap mode when the number of tasks is large because the port-swap mode can perform more tasks with fewer tractors than the ship-swap mode and because the port-swap mode can service receiving/delivery locations and finish ship loading/unloading more punctually than the ship-swap mode. Thus, this research provides a useful reference for road transport carriers and port firms to select the mode of tractor-and-semitrailer swap transport for ro-ro shipping.     

基于BIM应用的水运工程建设项目造价管理*

传统水运工程设计中二维图纸无法直观统计工程量和指导施工,而采用BIM技术可以实现设计的协同共享、碰撞检查及工程量统计,其建模过程与BIM模型的信息集成适用于造价管理中的各个阶段。依托湘江二级航道二期工程中大源渡航电枢纽二线船闸开展三维实景及水工建筑物的BIM建模,应用BIM技术复核工程量,使造价师从繁琐的计算工作中解脱出来,对水运工程建设项目造价综合管理具有较大的社会价值。     

垂向二维悬沙输移有限元数学模型

采用四节点任意四边形等参单元,根据G a lerk in有限元法进行数值离散,建立了潮汐河口沿宽度积分平均的垂向二维泥沙数学模型。模型中,对扩散项通过分步积分和G reen公式变换,精确满足了自由表面和底床边界条件;经采用有解析解的算例对模型进行验证,计算值和理论解相吻合。     

高压气囊工艺在沉箱码头施工中的应用

高压气囊顶升、拖运巨型沉箱工艺与传统的千斤顶、台车工艺相比，在工艺设备、经济成本、施工技术等方面具有较大的优越性；在自身浮游不稳定、吃水深度较大的巨型沉箱中的应用，更是扩大了气囊的应用范围，解决了浮船坞下潜深度不足的难题。     

铁路提速与军事运输

从世界交通发展趋势及两种交通体系特点简要论述铁路提速的必然性；铁路提速给军事运输带来的效果和新的要求；以及铁路提速后军事运输应改进的若干建议     

地铁公用移动通信引入系统浅析

本文主要介绍了地铁公用移动通信引入系统的常规方案,并指出了工程设计中需要重点考虑的问题,同时对工程的建设也提出了相关的建议。     

新编制办法下软件计算材料运杂费的算法解析

在铁路工程概预算的编制过程中，运杂费的计算一直是费时费力的一个环节。此文分析了运杂费的计算原理，介绍了其在软件中的计算方法，并说明了其在采用软件计算过程中应注意的一些变化，以便软件使用者能更好地利用软件分析运杂费。     

Travel patterns in Dutch metropolitan cities: The importance of external trips

Using a variety of data sources, decentralisation of population and employment in four Dutch urban areas (Amsterdam, Rotterdam, The Hague and Utrecht) over the last 20 years, is analysed. It is found that suburbanisation, plus an ever growing car share, has increased the number of external journeys related to the metropolitan cities enormously. With the use of the 1982 National Travel Survey, current travel patterns in and around the metropolitan cities are studied: the importance of external trips for urban transport planning shows clearly. They account for about half the number of city related car trips, and for nearly three quarters of the total vehicle kilometres of travel within the city.(requests for reprints)