西部地区公路快速客运系统关键技术研究

本篇依托＂西部地区公路快速客运系统关键技术研究＂项目,介绍了公路快速客运的概念、构成要素、服务对象、特征、发展现状及存在的主要问题,指出了公路快速客运系统的车辆、站场、服务、管理、信息等方面的关键技术,形成了公路快速客运系统评价模型,并提出了相应的快速客运发展对策及建议,为我国西部地区的公路快速客运系统建设与发展提供参考依据。     

Well-to-wheel costs,primary energy demand,and greenhouse gas emissions for the production and operation of conventional and alternative vehicles

This study provides a comprehensive comparison of well-to-wheel (WTW) energy demand, WTW GHG emissions, and costs for conventional ICE and alternative passenger car powertrains, including full electric, hybrid, and fuel cell powertrains. Vehicle production, operation, maintenance, and disposal are considered, along with a range of hydrogen production processes, electricity mixes, ICE fuels, and battery types. Results are determined based on a reference vehicle, powertrain efficiencies, life cycle inventory data, and cost estimations. Powertrain performance is measured against a gasoline ICE vehicle. Energy carrier and battery production are found to be the largest contributors to WTW energy demand, GHG emissions, and costs; however, electric powertrain performance is highly sensitive to battery specific energy. ICE and full hybrid vehicles using alternative fuels to gasoline, and fuel cell vehicles using natural gas hydrogen production pathways, are the only powertrains which demonstrate reductions in all three evaluation categories simultaneously (i.e., WTW energy demand, emissions, and costs). Overall, however, WTW emission reductions depend more on the energy carrier production pathway than on the powertrain; hence, alternative energy carriers to gasoline for an ICE-based fleet (including hybrids) should be emphasized from a policy perspective in the short-term. This will ease the transition towards a low-emission fleet in Switzerland.     

Chemical characteristics of the surface soil,herbaceous cover and organic layer of a compacted skid road in a fir (Abies bornmulleriana Mattf.) forest

This study looks at the impacts of timber skidding in a pure fir plantation forest. It compares properties of herbaceous cover, organic layer and surface soil on the skid road and on adjacent undisturbed area. N, P, K, Ca, Mg, Na, Fe, Zn, Mn and Cu are quantified and the mass of herbaceous cover and organic layer, and sand, silt, clay rates, bulk density, compaction and pH of soils were assessed. Both the herbaceous cover and organic layer mass on the skid road were significantly lower than the undisturbed area. The soil of the skid road also had higher bulk density and compaction, and lower organic carbon rates producing much denser and compacted soils. Only P concentration in herbaceous cover samples from skid road was significantly higher, while Ca and Mg contents were considerably lower than undisturbed area. There were no significantly differences in N, K, Na, Fe, Zn, Cu and Mn concentrations of herbaceous cover. Compared to the undisturbed area, the organic layer of the skid road had particularly low K, Na, Fe, Zn, Cu and Mn contents. At 0–5 cm soil depth, P and Fe contents were significantly lower than for undisturbed area but there were no major differences at depth of 5–10 cm.     

Evaluating Key Resources and Capabilities for Liner Shipping Services

Abstract

This paper empirically evaluates key resources and capabilities in the liner shipping context. Based on a factor analysis, three resource dimensions are identified: marine equipment, information equipment, and corporate image; whereas seven capability dimensions are identified: purchasing, operation, human resource management, customer service, information integration, pricing, and financial management. The findings suggest that operation capability is perceived as the most important dimension, followed by customer service, human resource management, information integration, pricing purchasing, and financial management. Results indicate that four dimensions are found that significantly differ between shipping companies and agencies: marine equipment, information equipment, operation, and information integration. The theoretical and managerial implications of the research findings are discussed.     

Representing and estimating interactions between activities in a need-based model of activity generation

Although several activity-based models made the transition to practice in recent years, modeling dynamic activity generation and especially, the mechanisms underlying activity generation are not well incorporated in the current activity-based models. For instance, current models assume that activities are independent, but to the extent that different activities fulfill the same underlying needs and act as partial substitutes, their interactions/dependencies should be taken into account. For example, recreational, leisure, and social activities tend to be partly substitutable since they satisfy a common need of relaxation, and when undertaken together with others, social needs will be satisfied as well. This paper describes the parameter estimation of a need-based activity generation model, which includes the representation of possible interaction effects between activities. A survey was carried out to collect activity data for a typical week and a specific day among a sample of individuals. The diary data contain detailed information on activity history and future planning. Estimation of the model involves a range of shopping, social, leisure, and sports activities, as dependent variables, and socioeconomic, day preference, and interaction variables, as explanatory variables. The results show that several person, household, and dwelling attributes influence activity-episode timing decisions in a longitudinal time frame and, thus, the frequency and day choice of conducting the social, leisure, and sports activities. Furthermore, interactions were found in the sense that several activities influence the need for other activities and some activities affect the utility of conducting another activity on the same day.     

A cognitive framework to plan for the future of transportation

ABSTRACT

Automated, connected, electrified, and shared mobility will be cornerstones of the transportation future. Research to quantify the potential benefits and drawbacks of practice, and to identify barriers to adoption, is the first step in any strategic plan for their adoption. However, uncertainties, complexity, interdependence, and the multidisciplinary nature of emerging transportation technologies make it difficult to organize and identify focused research. The contribution of this work is a cognitive framework to help planners and policymakers organize broad topics, reveal challenges, discover ideas for solutions, quantify potential impacts, and identify implications to guide preparation strategies. The authors provide example cognitive frameworks for connected, automated, and electrified vehicles.     

Random parameter models for estimating statewide daily bicycle counts using crowdsourced data

Persistent lack of non-motorized traffic counts can affect the evidence-based decisions of transportation planning and safety-concerned agencies in making reliable investments in bikeway and other non-motorized facilities. Researchers have used various approaches to estimate bicycles counts, such as scaling, direct-demand modeling, time series, and others. In recent years, an increasing number of studies have tried to use crowdsourced data for estimating the bicycle counts. Crowdsourced data only represents a small percentage of cyclists. This percentage, on the other hand, can change based on the location, facility type, meteorological, and other factors. Moreover, the autocorrelation observed in bicycle counts may be different from the autocorrelation structure observed among crowdsourced platform users, such as Strava. Strava users are more consistent; hence, the time series count data may be stationary, while bicycle demand may vary based on seasonal factors. In addition to seasonal variation, several time-invariant contributing factors (e.g., facility type, roadway characteristics, household income) affect bicycle demand, which needs to be accounted for when developing direct demand models. In this paper, we use a mixed-effects model with autocorrelated errors to predict daily bicycle counts from crowdsourced data across the state of Texas. Additionally, we supplement crowdsourced data with other spatial and temporal factors such as roadway facility, household income, population demographics, population density and weather conditions to predict bicycle counts. The results show that using a robust methodology, we can predict bicycle demand with a 29% margin of error, which is significantly lower than merely scaling the crowdsourced data (41%).     

Comparison of car ownership models

Car ownership models found in the academic literature (with a focus on the recent literature and on models developed for transport planning) are classified into a number of model types. The different model types are compared on a number of criteria: inclusion of demand and supply side of the car market, level of aggregation, dynamic or static model, long‐ or short‐run forecasts, theoretical background, inclusion of car use, data requirements, treatment of business cars, car‐type segmentation, inclusion of income, of fixed and/or variable car cost, of car quality aspects, of licence holding, of sociodemographic variables and of attitudinal variables, and treatment of scrappage.     

沈家门港海底沉管隧道设计介绍

沉管法是修建水下隧道的一种先进施工方法,其设计需考虑结构、施工工艺、水文地质条件、运营等众多因素的影响。针对隧道工程和水文地质、沉管结构、管段沉放水流阻力等条件,以及系缆柱、接头防水、最终接头、工程耐久性等措施,对沈家门港海底沉管隧道工程的设计进行了分析。分析结果表明:沉管管段既要满足结构力学要求,又要满足施工中起浮运输及运营期抗浮、稳定性、耐久性要求,综合考虑各种因素才能设计出符合要求的沉管隧道结构。     

Persistence of walking in Chile: lessons for urban sustainability

ABSTRACT

An extensive body of work from the urban planning, health, and other disciplines has documented the importance of walking to urban sustainability from health, safety, security, environmental and other perspectives. These studies come mainly from countries in North America and Europe, where the majority of the population relies on cars for transportation. Notwithstanding, in many countries in the Global South, walking remains a majority transport mode, while cars increasingly dominate the urban streetscape, but are accessible only to a minority of the population. Chile provides fertile terrain for studying this phenomenon. This article reviews current practice and recent research of walking in Chile, in light of international findings regarding walkability, equity and urban sustainability. To elaborate an overview of the depth and breadth of walking in Chile, an interdisciplinary team conducted a literature review, examined relevant case study material from experience from Chile and in particular from Santiago, and triangulated this mainly qualitative data with results from the origin-destination survey applied in Chile’s main cities, Chilean traffic safety data) and results from official transport reports of other Latin American cities [Tirachini, A. (2019). South America: The challenge of transition. In J. Stanley & D. Hensher (Eds.), A research agenda for transport policy. Northampton, MA: Edward Elgar Publishing]. Findings show that despite priority public investments that have largely prioritised infrastructure for cars, walking in Chile has remained as the majority transport mode up until today, especially for lower-middle income groups, and particularly for care-related tasks performed mainly by women. In this sense, walking in Chile has proven remarkably persistent. The importance of walking as the main transport mode, against the odds, reflects economic, cultural, and urban form determinants, which are explored in this article. Furthermore, a recent upsurge in public interest and community design initiatives to improve walking, particularly the generation of a Chilean approach to “complete streets” has emerged, opening up opportunities to challenge Chile’s version of automobility in favour of more equitable, active and public transportation modes. There is, therefore, in Chile an opportunity to prioritise the walking mode, improve infrastructure for walkers and build from preserving current high pedestrian modal shares, rather than having to reverse widespread car use, as occurs in many countries in Europe and North America. This potential is highly relevant as these conditions are similar to those in other Latin American cities and, potentially, other cities elsewhere in the Global South.     

公路山岭隧道衬砌结构补漏技术研究进展

为全面了解公路山岭隧道衬砌结构补漏技术的最新研究进展,文章通过对既有公路山岭隧道的调查和统计,结合大量的文献资料,从防排水设计、材料和施工等方面分析了渗漏现象的本质,明确了隧道抗渗防漏的薄弱部位和保证补漏效果的关键环节;从衬砌混凝土、施工缝、变形缝和活裂缝等方面,介绍了当前国内外补漏技术的最新研究成果(包括补漏涂材、构造补漏和施工工艺等);并探讨了当前隧道补漏技术存在的问题和发展的新趋势。     

The Gothenburg traffic restraint scheme

Officials at various levels around the world are getting increasingly worried about the growth in automobile ownership and all the associated environmental problems that this implies. Voices are often heard advocating the exclusion of automobiles from the central areas of cities, much easier to say than to realise, unless the area is entirely reconstructed under a comprehensive redevelopment scheme, as, for instance, in the city of Västeras, Sweden. Another possible solution is to introduce some type of traffic restraint scheme involving compulsory rearrangement of the vehicular flow through the central area.The report deals firstly with an experiment carried out during the highly intensive, pre-Christmas shopping days in December 1969, when parts of the central business area of the city of Gothenburg, Sweden (population around 450,000) were closed to all unauthorised vehicles. The experience gained with this scheme was valuable when the next stage was being planned, i.e., a permanent traffic restraint scheme which was put into effect on August 18, 1970. Most of the report deals with the objectives, planning, realisation, and experience of the traffic restraint scheme, which involved dividing the central business area into five separate zones. During the first six months, several surveys were conducted to establish the impact of the scheme on vehicular flow, parking, pedestrian flow, public transport, accidents, air pollution, noise, and retail businesses.The scheme put into operation in Gothenburg has been a great success, having accomplished most of its objectives, and will be expanded to cover a still larger area in subsequent years.This paper is an amended and updated version of one originally prepared in May 1971 for the Environment Directorate of the Organisation for Economic Cooperation and Development, whose permission to publish is gratefully acknowledged.     

沥青混凝土路面平整度差的成因及对策研究

结合G205、G312等沥青路面不同程度出现的沉陷、接缝台阶、波浪、车辙、桥涵与路面接茬不平、跳车等路面不平整现象,分析、探讨造成沥青路面平整度差的路基、桥涵、路面基层施工方面、材料方面以及路面摊铺、碾压等主要原因,并提出相应对策措施。     

影响含有凹痕管道运行寿命的因素研究

国外管道设计标准普遍采用凹痕深度对管道凹痕是否需要修复进行评估,但是,很多满足标准中凹痕深度要求的凹痕仍会发生失效。因此,国外许多研究机构对含有凹痕的管道进行了大量的试验研究。通过比较现场和试验数据,并使用计算软件对管道的压力进行分析,试图从各个方面找出影响含有凹痕的管道运行寿命的因素。文中对此进行了总结,介绍了凹痕长度、凹痕深度、凹痕肩部坡度、凹痕尖度、管道几何形状、管道材料、运行压力、焊缝、壁厚变薄对管道上凹痕疲劳行为的影响。最后得出了结论．并提出建议。     

A review of the state of the art of personal rapid transit

The paper begins with a review of the rational for development of personal rapid transit, the reasons it has taken so long to develop, and the process needed to develop it. Next I show how the PRT concept can be derived from a system‐significant equation for life‐cycle cost per passenger‐mile as the system that minimizes this quantity. In the bulk of the paper I discuss the state‐of‐the‐art of a series of technical issues that had to be resolved during the development of an optimum PRT design. These include capacity, switching, the issue of hanging vs. supported vehicles, guideways, vehicles, control, station operations, system operations, reliability, availability, dependability, safety, the calculation of curved guideways, operational simulation, power and energy. The paper concludes with a listing of the implications for a city that deploys an optimized PRT system.     

新型轻质直立式路堤的施工过程控制

针对高掺量粉煤灰泡沫轻质土的轻质、可流动、及固化直立特性,采用过程控制的施工方法,并结合广明高速公路FD段新型轻质直立式路堤的施工情况,严格按照设计指标要求,从附属工程、设备要求、施工方式、湿密度、流值及气泡密度等方面开展控制,以期按质保量完成工程建设。     

The contribution of road traffic to particulate matter and metals in air pollution in the vicinity of an urban road

A detailed investigation was conducted to study the sources of particulate matter in the vicinity of an urban road in Žilina. To determine the amount of particulate matter (PM₁₀, PM_2.5 and PM₁) present in the ambient air, a reference gravimetric method was used. The main objective of this contribution was to identify the sources of these particles by means of statistical methods, specifically principal component analysis (PCA), factor analysis (FA), and absolute principal component scores (APCS), as well as using the presence of 17 metals in the particulate matter (Na, Mg, Al, Ca, V, Cr, Fe, Mn, Ni, Cu, Zn, As, Mo, Sb, Cd, Ba, Pb). To identify the metals in the particulate matter samples and to determine their abundances, spectroscopic methods were used, specifically inductively coupled plasma mass spectrometry (ICP-MS). Each of these metals may come from a specific source, such as the burning of fossil fuels in fossil fuel power plants; local heating of households; the burning of liquefied fossil fuels in the combustion engines of vehicles; the burning of coal and wood; non-combustion related emissions resulting from vehicular traffic; resuspension of traffic-related dust; and industry. Diesel vehicles and non-combustion emissions from road traffic have been identified as two key sources of the particulate matter. The results reveal that non-combustion emissions, which are associated with the elements Na, Fe, Mn, Ni, Zn, Mo, Sb, Cd, and Pb, are the major contributors, followed by combustion emissions from diesel vehicles, which are associated with the elements Mg, Ca, and Ba.     

Values of travel time in Europe: Review and meta-analysis

This paper reports the most extensive meta-analysis of values of time yet conducted, covering 3109 monetary valuations assembled from 389 European studies conducted between 1963 and 2011. It aims to explain how valuations vary across studies, including over time and between countries. In addition to the customary coverage of in-vehicle time in review studies, this paper covers valuations of walk time, wait time, service headway, parking space search time, departure time switching, time in congested traffic, schedule delay early and late, mean lateness and the standard deviation of travel time. Valuations are found to vary with type of time, GDP, distance, journey purpose, mode, the monetary numeraire and a number of factors related to estimation. Model output values of time compare favourably with earnings data, replicate well official recommended values obtained from major national studies, and are transferable across countries. These implied monetary values serve as very useful benchmarks against which new evidence can be assessed and the meta-model provides parameters and values for countries and contexts where there is no other such evidence.     

济南市快速公交系统建设实践

分析了济南市BRT系统的建设背景,提出了双快模式、左右开门可以转换、两种车辆运行等的济南模式。在简述了首期BRT系统六条线路的工程概况后,重点从专用路权、站台、车辆、运营线网、信息化和运营管理等方面阐述了BRT系统的六个组成部分。通过对比分析和系统总结,利用大量数据说明了济南市BRT系统的特征与优势,并取得了较好的运营效果。BRT改善和提升了城市交通环境、优化了城市居民出行结构,是一种适合于济南市目前发展阶段的发展模式。     

Optimizing the process of designing and calculating railway catenary support infrastructure using a high-productivity computational tool

The process of designing and calculating railway catenary infrastructure, as the way it is carried out currently, is very complex and time consuming. It is necessary expert knowledge of different fields, like design and structural calculus, technical security, legal normative, topography, etc. This process consists of several stages aimed at choosing a design, checking requirements, and calculating structural feasibility, so the communication among the experts may be quite slow. In order to reduce time and effort invested in this process, we propose a system that allows to automate its stages and tasks. Our system provides a valid solution per structure, that complies with design and structural constraints, and with existing railway regulations. The proposed system has been integrated in a high-productivity software tool, that avoids human mistakes due to hand-calculation, allows users a fast design and calculation, and exploits the ability of current computers to run tasks concurrently so as to speed up the process. The computational performance and complexity of the tool, as well as statistics values, are analysed by designing and calculating up to 2048 heterogeneous support structures. Besides, the tool is evaluated through a study case based on a real railway route, obtaining an overall improvement of 82.33% in time invested over the existing process.