Some lessons from the LRT in Tunis and the transferability of experience

Considering the debate about the technological options to get a modern mass transport supply in developing cities the experience of Tunis is very interesting to analyse and to appraise as this city is operating a LRT network since 1985. This paper presents the elements of success of this experience (satisfying level of ridership, moderate cost of investment, coverage of operating cost by receipts, accessibility of the central area, etc.) but also its limits coming from the limited capacity at the city scale and the inability to stop the extension of the car use in the city. That means this project has to be completed by another one, more complex and costly which would consist of a railway regional network, which is now studied in detail.A short comparison is made with other cities in Maghreb (Algiers, Casablanca) experimenting also the design of metro projects which were more ambitious but with less success as they could not yet be implemented. Among the lessons thrown from this experience one insists on the importance of studies which have accompanied the design and the implementation of the project.     

An investigation of passenger interchange and train standing time at LRT stations: (ii) Estimation of standing time

The standing-time of trains at urban rail stations is pertinent to determining the line capacity and fleet size. The assumption of uniform boarding and alighting leads to under-estimation of the standing time. It is shown that the train standing-time is related to the fraction of boarders and the maximum demand for boarding and alighting at a door. It is further shown that the probability distribution of passengers at a door depends on the platform entrance locations. A methodology that takes into account the above factors is proposed for estimating the train standing-time.     

An investigation of passenger interchange and train standing time at LRT stations: (i) Alighting,boarding and platform distribution of passengers

The train standing-time at a station is a determinant of the line capacity and the necessary fleet-size. Its determination is usually based on the assumption that boarding and alighting is uniform at all doors of a train. Uniform boarding and alighting is conceivable if passengers distribute themselves uniformly on station platforms while waiting for trains. The validity of the uniformity assumptions is tested using data from two stations (one CBD, one suburban) of the Calgary, Alberta LRT system. It is shown that passenger distribution on the platform, alighting and boarding is not uniform and is closely related to the location of platform access points. Some strategies that will encourage uniformity are discussed. However, procedures that can estimate the standing time for non-uniform boarding and alighting need to be developed.     

Defining the functional and physical compatibility of a modernized tramway rolling stock with a newly planned LRT system: a case study of Belgrade

According to the Belgrade Master Plan for 2021, the public transportation system for the city and its region will include three rail modes: a modernized existing tramway, regional rail, and a new light rail transit (LRT) mode. In the coming years all three rail modes should be developed simultaneously and in a coordinated manner. The introduction of LRT is to be realized in several phases, and its first line will partially follow the alignment of an existing tramway line. As the present tramway vehicles are obsolete, new rolling stock must be designed and purchased to be compatible with many of the elements of the LRT. Ways to adjust the new tramways to the LRT rolling stock represent the central topic of this paper. The basic technical and operating characteristics of the new tramway are defined with respect to their required compatibility with the LRT stock and infrastructure.     

Energy use in passenger transport in OECD countries: Changes since 1970

This paper analyzes some of the changes that took place in the structure of energy use for passenger travel in industrialized countries. Data is presented on energy use and travel activity for the four major modes of travel — automobile, bus, rail and air — for eight OECD countries: the United States, Japan, the United Kingdom, West Germany, France, Italy, Sweden, and Norway. We use the Laspeyres and Divisia indices to analyze the causes of the change in energy use between 1970 and 1987. The total change in energy use for travel is explained by changes in domestic passenger transport volumes, the mix of modes of travel, and the energy intensities of each mode. We have found two important effects that have a fundamental impact on energy use for travel since 1970. First, shifts among modes of transport towards more energy-intensive ones and large increases in volumes of travel (measured in passenger-kilometers) increased energy use for travel in many OECD countries, often more rapidly than the overall growth in GDP. Second, energy intensities, measured in mJ/passenger-kilometer, of passenger transport fell only in a few countries between 1970 and 1987. Even though individual automobiles have become more energy-efficient, greater size, power, and weight, worsening traffic conditions in Japan and Europe, and fewer people in cars restrained or even offset efficiency improvements. Particularly notable are the increases in intensities in Japan and Germany. The most important exception to this trend was the United States, but the intensities of land-based travel remain higher there than in most other countries. These findings lead to a pessimistic outlook for future energy use for travel. After all, if little or no energy was saved during the decades of high fuel prices, what can be expected in the 1990s?     

Seaport research: A structured literature review on methodological issues since the 1980s

This study aims to investigate how seaport research has been conducted from the methodological perspective. To this end, this study reviews published port literature for the last three decades (1980-2000s). The investigation primarily categorises the literature according to various methodological issues such as research paradigm, research strategy, base-disciplines, research methods and analysis techniques in order to provide meaningful implications on methodological evolution in seaport research for the period. This study suggests methodological bias in port research to a positivistic paradigm, following a quantitative trajectory moving from conceptual to empirical studies. In addition, the increased use of mathematical modelling and advanced statistical analysis methods is clearly observed. The introduction of advanced analytical tools used in other academic disciplines facilitates discussions in particular research area and amplifies the literature in those areas. This paper also suggests research gaps from the methodological perspective and implications for future port research.     

Dynamics of highway design for safety

An important aspect of improving highway safety lies in designing the geometric features of roadways in response to the characteristics and behavior of drivers. This is being applied to specific features of highways with evidence of improvement in operation and safety. However, much more can be accomplished. There is now available additional operational experience and observations, which can assist the driver's task in vehicle control and guidance, but which have not yet been fully reflected in design criteria. If judiciously applied, such measures could further enhance highway safety. The paper addresses itself mainly to this aspect and presents the thesis: when all known or accepted safety features and techniques are applied fully to a highway project, it may be expected that a significant improvement in safety will be achieved. An actual project is suggested to validate this approach.     

计算流体动力学(CFD)在配管中的应用

随着软件技术的发展,计算流体动力学(CFD)在炼油化工行业中得以应用。文中以计算流体动力学模拟软件FLUENT为例,详细描述了利用计算流体动力学方法优化分支配管结构,结果表明CFD方法能够科学直观地解决此类配管优化问题,有着广泛的应用前景。     

基于系统动力学的重型车NOX排放量预测模型研究

为预测减排技术对我国机动车氮氧化物减排工作的影响,采用系统动力学方法,将机动排放标准比例,减排技术采用比例和保有量之间的关系进行分析,建立了氮氧化物(NO_X)排放量预测模型,并根据大型客车的数据进行了验证,得到了宏观的减排效果分析。对2018年到2025年的减排结果进行了预测,结果表明,该预测模型可有效计算我国氮氧化物的排放量,得到的结果基本可以反映未来大型客车氮氧化物的排放状况。     

Transport infrastructure and regional economic growth: evidence from China

This article develops a multi-dimensions measurement of transport infrastructure and examines the linkage between transport infrastructure and regional economic growth. A panel data model is estimated using data from a sample of 31 Chinese provinces from 1998 to 2007. The results provide strong evidence that transport infrastructure plays an important role in economic growth. Both land transport and water transport infrastructure have strong and significant impacts, while the contribution of airway transport infrastructure is weak. Furthermore, land transport infrastructure contributes more to economic growth in locations with poor land transport infrastructure, while the investment in water transport infrastructure contribute positively to economic growth only after the investment scale exceeds a threshold level. These results are robust to a variety of alternative methods, the exclusion of possible outliers, and consideration of endogeneity. A retrospective analysis shows that uneven distribution of transport infrastructure is an important reason behind economic disparities across Chinese regions.     

Technical change and productivity growth in airports: A case study

This paper analyses the rate of technical progress at Portuguese airports between 1990 and 2000, using a stochastic cost frontier method. A translog frontier model is used and the maximum likelihood estimation technique is employed to estimate the empirical model. We estimate the efficient scores and disentangle the rate of technical progress into three components: pure technical progress, non-neutral technical progress and scale-augmenting technical progress. The results show that the average score is 88%, denoting a relatively high degree of waste, despite the fact that technical change contributed to a reduction in costs.     

The future tourism mobility of the world population: Emission growth versus climate policy

Much of global passenger transport is linked to tourism. The sector is therefore of interest in studying global mobility trends and transport-related emissions. In 2005, tourism was responsible for around 5% of all CO₂ emissions, of which 75% were caused by passenger transport. Given the rapid growth in tourism, with 1.6 billion international tourist arrivals predicted by 2020 (up from 903 million in 2007), it is clear that the sector will contribute to rapidly growing emission levels, and increasingly interfere with global climate policy. This is especially true under climate stabilisation and “avoiding dangerous climate change” objectives, implying global emission reductions in the order of −50% to −80% by 2050, compared to 2000. Based on three backcasting scenarios, and using techniques integrating quantitative and qualitative elements, this paper discusses the options for emission reductions in the tourism sector and the consequences of mitigation for global tourism-related mobility by 2050. It ends with a discussion of the policy implications of the results.     

An Analysis of the Dynamics of Ownership,Capacity Investments and Pricing Structure of Ports

With more than 80% of the world's cargoes being transported by sea, effective port management is critical to the well-being of the global economy. This study models the effects of port ownership and governance on capacity investment and pricing structure, and these changes' implications on port service level and social welfare. The study argues that capacity investment and pricing are significantly influenced by a port's ownership form, and the different levels of government involved. Inter-port competition leads to increased capacity investments by private investors and local authorities, which can be either higher or lower than social optimal level. Therefore, it is important for policymakers to consider the effects of institutional and competition factors in port reform initiatives.     

Tourism growth versus airport environmental capacity: An application of Ramsey pricing to Spanish tourist airports

Airport infrastructure in many countries is being up-graded to meet the growing demands of tourism, and air travel more generally, but this poses problems for sustainable development. Thus, there is the need to establish an alternative to the traditional airport pricing structure for landing fees so as to reflect the true cost that air transports imposes on others. This paper analyses one application of Ramsey pricing to some Spanish tourist airport that embraces environmental as well as conventional financial costs.     

The transition to electric bikes in China: history and key reasons for rapid growth

Annual electric bike (e-bike) sales in China grew from 40,000 in 1998 to 10 million in 2005. This rapid transition from human-powered bicycles, buses and gasoline-powered scooters to an all-electric vehicle/fuel technology system is special in the evolution of transportation technology and, thus far, unique to China. We examine how and why e-bikes developed so quickly in China with particular focus on the key technical, economic, and political factors involved. This case study provides important insights to policy makers in China and abroad on how timely regulatory policy can change the purchase choice of millions and create a new mode of transportation. These lessons are especially important to China as it embarks on a large-scale transition to personal vehicles, but also to other countries seeking more sustainable forms of transportation.

基于SD的机场旅客安检系统设备及安检员需求研究

为了合理分配设备及安检员数量,研究了机场两阶段旅客安检系统中设备及安检员的需求问题。运用系统动力学的方法,建立了机场旅客安检系统的微观模型。模型通过检验后,设立了低、中、高3个风险等级的安检模式,比较现阶段客流量与客流量增长38%两种情景下的设备和安检员的需求差异。仿真结果表明:相对于现阶段,客流量增长38%时,金属探测门需要额外增加7台;在满足安检员工作强度的情况下,客流量增长38%时,机场安检员的最大在岗数量随着安检等级的增加而提高。