The regional impact of the TGV

Evidence on the regional impact of the TGV high speed rail line between Paris and Lyons is provided, on the basis of surveys carried out both before and after its inauguration. The timing of the TGV and the nature of the surveys are explained, while the analysis contrasts the impact on the Paris and Rhone-Alps regions at each end of the TGV line. Tourism and service industries are the main subjects of the research.Original in French.     

纽约州交通局的桥梁检查计划

在过去20年里,纽约州交通运输部(NYSDOT)已对全州1.74万公路桥梁的桥梁状况的检查和评价计划进行了管理和监督.该计划的首要目标是确保纽约的桥梁保持结构和运营安全,数据收集和报告是为桥梁所有者提供评估桥梁的状态和维护需求的主要信息来源.本文概述了纽约州交通部的桥梁检查和评价计划,包括项目范围、主要要求和特点、资源和数据应用.     

Possibility of jamming and wedging in the three-piece trucks of a moving freight car

Three-piece trucks have some drawbacks, particularly unstable operation of the friction wedge damping system. One of the principal features of systems of this kind is the possibility of jamming and wedging. This work is devoted to mathematical and numerical modeling of the plane motion of a freight car with allowance for the mobility of the wedges and then for the compliance of the contacting bodies and to the study of the conditions for the onset of jamming and wedging when the car is in motion.     

Relationship between proximity to transit and ridership for journey-to-work trips in Chicago

The use of privately owned vehicles (POVs) contributes significantly to US energy consumption (EC) and greenhouse gas emissions (GHGe). Strategies for reducing POV use include shifting trips to other modes, particularly public transit. Choices to use transit are based on characteristics of travelers, their trips, and the quality of competing transportation services. Here we focus on the proximity of rail stations to trip origins/destinations as a factor affecting mode choice for work trips. Using household travel survey data from Chicago, we evaluate the profile of journey-to-work (JTW) trips, assessing mode share and potential for more travelers to use rail. For work trips having the origin/destination as close as 1 mile from rail transit stations, POVs were still the dominant travel mode, capturing as much as 61%, followed by rail use at 14%. This high degree of POV use coupled with the proportion of JTW trips within close proximity to rail stations indicated that at least some of these trips may be candidates for shifting from POV to rail. For example, shifting all work trips with both the origin/destination within 1 mile of commuter rail stations would potentially reduce the energy associated with all work-related POV driving trips by a maximum of 24%. Based on the analysis of trips having the origin and destination closest to train stations, a complete shift in mode from POV to train could exceed CO₂ reduction goals targeted in the Chicago Climate Action Plan. This could occur with current settlement patterns and the use of existing infrastructure. However, changes in traveler behavior and possibly rail operation would be necessary, making policy to motivate this change essential.     

Analyzing loss aversion and diminishing sensitivity in a freight transport stated choice experiment

Choice behaviour might be determined by asymmetric preferences whether the consumers are faced with gains or losses. This paper investigates loss aversion and diminishing sensitivity, and analyzes their implications on willingness to pay and willingness to accept measures in a reference pivoted choice experiment in a freight transport framework. The results suggest a significant model fit improvement when preferences are treated as asymmetric, proving both loss aversion and diminishing sensitivity. The implications on willingness to pay and willingness to accept indicators are particular relevant showing a remarkable difference between symmetric and asymmetric model specifications. Not accounting for loss aversion and diminishing sensitivity, when present, produces misleading results and might affect significantly the policy decisions.     

The utilisation and user characteristics of Uber services in London

ABSTRACT

Ridesourcing services such as Uber are nowadays a common feature within available transport options of many cities around the world (E.g. London & San Francisco). There has been much publicity about the potential impacts of ridesourcing services and how (or if) they should be managed or regulated without an objective understanding of who uses these services and why, as well as its current and future implications for public transport (PT).

Ridesourcing is part of a broader tech-driven, mobile app-based sharing phenomenon – the ‘sharing economy’ – which has disrupted traditional market models and industries, for example, the transport industry, where new players such as Uber have emerged and have quickly become part of the urban transport landscape. Uber has been at the forefront in disrupting the transport sector since its first launch in 2010 (San Francisco, USA). Since its launch, Uber has generated extensive media coverage and debate among policymakers, transport planners and transport authorities on how these services are affecting traditional transport modes such as buses and taxis. However, without objective empirical data – in terms of impacts on trip making characteristics, PT ridership and congestion – policymakers and transport regulators are yet to fully understand the real impacts ridesourcing services are having on the transport network.

This paper is part of broader research that aims to provide insights and empirical-based evidence on how Uber services are used (UberX and Uberpool) in London. A comprehensive survey was undertaken using a detailed questionnaire, issued to UberX and Uberpool users in London to gather detailed data on who uses the Uber services, why they use it and what are the trip purposes, in order to understand Uber user demographics and what effects (if any) Uber services are having on PT usage and trip making characteristics in London. The final findings provide important insights on Uber user demographics, trip purposes, types of trips replaced, impact on car ownership and why travellers use Uber services.     

Wind-induced mesoscale circulation off the Ebro delta, NW Mediterranean: a numerical study

It is well known that the general circulation on the Catalan continental slope is dominated by a quasi-permanent southwestward geostrophic jet associated to the so-called Catalan front [Millot, C., 1987. Circulation in the western Mediterranean sea. Oceanol Acta 10, 143–149; Font, J., Salat, J., Tintoré, J., 1988. Permanent features of the circulation in the Catalan Sea. Oceanol. Acta 9, 51–57]. On the continental shelf, however, the flow is modified by the action of friction which enhances also other nonlinear interactions. Several authors have hypothesized that the shelf circulation is anticyclonic north of the Ebro delta [Salat, J., Manriquez, M., Cruzado, A., 1978. Hidrografia del golfo de Sant Jordi. Campaña Delta (Abril 1970). Investigación Pesquera 42 (2), 255–272; Ballester, A., Castellví, J., 1980. Estudio hidrográfico y biológico de las plataformas continentales españolas: I. Efecto de los efluentes de una planta de energía nuclear en el Golfo de San Jorge (Febrero 1975–Octubre 1976). Informes Técnicos del Instituto de Investigaciones Pesqueras 76, 70 pp.]. A quasi-3D finite element code based on the shallow-water equations has been used to explore the effect of several mechanisms which might be responsible for such a local circulation pattern, and in particular of wind. The obtained numerical results suggest that the basic anticyclonic structure of the mean flow is controlled by the bathymetry and that the clockwise-rotating mean flow pattern is not a permanent circulation feature. It is seen that the characteristic local wind stress fields—computed through interpolation of the records of a local network of meteo stations—may ‘enhance' or ‘delete' the anticyclonic gyre depending on the sign of their relative vorticity. According to the analysis of a 2-yr record of local wind data, the net contribution of wind events with a duration longer than 24 h is to reinforce the anticyclonic circulation (over 70% of these wind fields supply negative relative vorticity to the study area).     

路面横坡度与大空隙沥青混合料渗水性能的关系分析

通过浸水马歇尔试验、冻融劈裂试验、车辙试验以及改进的渗水试验,来评价同一种级配不同沥青的大空隙沥青混合料的水稳定性、高温稳定性和渗水性能等,模拟在不同路面横坡度下大空隙沥青混合料的横向及竖向渗水系数与横坡度之间的关系,回归了路面横坡度与渗水系数之间的线性关系。     

微表处养护技术在西蓝高速公路上的应用

介绍了微表处养护技术在西(安)-蓝(田)高速公路养护工程中的应用,并探讨了材料的性质、配合比的设计和施工质量控制.认为微表处养护技术对高速公路预防性养护具有特殊意义.     

浅谈大体积混凝土裂缝

针对大体积混凝土结构经常出现表面和内部裂纹的问题,根据大型工程中的实践经验提出自己的看法和观点。