首汽出租:到底我有多特殊

北京首汽股份有限公司(简称"首汽")总经理助理梁海晨负责管理占首汽1/5的收入、1/3利润的所有客运业务,其分管的940部高档商务车、880部大中型旅游客车和5250部城市出租车在北京大街上相当活跃,其中尤以出租车最甚.     

The authors in this issue

Cambridge is a small free standing city in the UK with a population of 105 000. In recent years it has endured a worsening congestion problem essentially as a result of employment growth within the city and the narrow street layout. This is not a unique problem but one which is particularly acute in historic cities. In 1990, Congestion Metering was advanced, in addition to a number of other measures, as a means of managing traffic demand within the city. It has generated a great deal of interest internationally, particularly the field trial which took place in October 1993. This was the first time that any form of road pricing had been demonstrated practically in the UK. The aim of this article is to provide a review, establishing why the idea of Congestion Metering was originally considered and why, at least in the short to medium term, it is unlikely to be implemented in a Cambridge context. The process by which, if adopted, it is envisaged that Congestion Metering would be introduced is outlined, and the relative merits and potential weaknesses of such a demand management measure. Finally, the author considers the real problem of ‘public scepticism’ which needs to be addressed if Congestion Metering is to avoid the pitfalls which have bedevilled other road pricing schemes world‐wide.     

The authors in this issue

This paper analyses the impacts on a particular region of a recent policy change regarding public transit subsidy in New Zealand, under which the contributions of local authorities are increased from 0 to 50% of net direct expenditures. The options open to the community are examined and their effects on regional income, future development and social equitability are analysed. It also illustrates the cost effectiveness of a natural monopoly under increased accountability.     

The authors in this issue

This paper considers the main road-traffic parameters that determine air pollution, i.e. the total volume of traffic, road speeds and the composition of the vehicle fleet. Changes in the amounts of pollutants emitted, and the importance of each of the three parameters, have been computed by using a traffic assignment model, which also represents emission factors. The types of policies that may be implemented to reduce the environmental impact of transport are then considered. The study demonstrates, for example, that the impact of a deterioration in traffic conditions is limited in comparison with the effect of forecast increases in traffic and improvements in the environmental performance of vehicles. As a consequence, if cities and urban transport are to achieve sustainable development, urban expansion must take place in a controlled way.     

我国首部道路危货运输安全指引手册诞生

2006年3月21日,由广东省交通厅、盛世报堂传播机构(TRANSPORTMEDIA)、<运输经理世界>杂志社联合编制的<广东省道路危险货物运输安全指引>诞生. 该手册是我国首部关于道路危货运输安全的指引手册,针对运输行业整体文化水平的特点,简明扼要地针对道路危险货物的承运、托运、驾驶、装卸、押运等过程的安全生产进行了知识和行为指引,以确保具体安全运输行为有文可循、有章可查、有法可依.     

A problem of limited-access special lanes. Part I: Spatiotemporal studies of real freeway traffic

Most special-use freeway lanes in the US, whether reserved for carpools, toll-paying commuters or both, are physically separated from the adjacent regular-use lanes by some form of barrier. Vehicle movements in and out of a special lane of this type are permitted only at select access points along the route. The barrier at each select point might open for a distance of 400 m or so. Limiting access in this way is said to reduce the “turbulence” that might otherwise occur were the special lane not to have a barrier, such that vehicles could instead enter or exit that lane anywhere along its length.Yet, real freeway traffic studied in spatiotemporal fashion shows that access points are prone to become bottlenecks. The problem occurs when traffic in the regular lanes becomes dense, as commonly happens during a rush. Drivers then seek refuge in the special lane in greater numbers. Since the vehicular maneuvers through the access point are focused within a limited physical space, they can become disruptive and further degrade traffic. Degradation can occur both in the special lane and in the adjacent regular ones. The damage can be worse than when there is no barrier to limit special-lane ingress and egress.The problem is shown to be reproducible across sites and across days at each site. Policy implications are discussed. Select designs and policies to address the problem are thereafter explored in Part II of the paper using traffic simulation.     

Mobility and environment improvement of signalized networks through Vehicle-to-Infrastructure (V2I) communications

Traffic signals, even though crucial for safe operations of busy intersections, are one of the leading causes of travel delays in urban settings, as well as the reason why billions of gallons of fuel are burned, and tons of toxic pollutants released to the atmosphere each year by idling engines. Recent advances in cellular networks and dedicated short-range communications make Vehicle-to-Infrastructure (V2I) communications a reality, as individual cars and traffic signals can now be equipped with communication and computing devices. In this paper, we first presented an integrated simulator with V2I, a car-following model and an emission model to simulate the behavior of vehicles at signalized intersections and calculate travel delays in queues, vehicle emissions, and fuel consumption. We then present a hierarchical green driving strategy based on feedback control to smooth stop-and-go traffic in signalized networks, where signals can disseminate traffic signal information and loop detector data to connected vehicles through V2I communications. In this strategy, the control variable is an individual advisory speed limit for each equipped vehicle, which is calculated from its location, signal settings, and traffic conditions. Finally, we quantify the mobility and environment improvements of the green driving strategy with respect to market penetration rates of equipped vehicles, traffic conditions, communication characteristics, location accuracy, and the car-following model itself, both in isolated and non-isolated intersections. In particular, we demonstrate savings of around 15% in travel delays and around 8% in fuel consumption and greenhouse gas emissions. Different from many existing ecodriving strategies in signalized road networks, where vehicles’ speed profiles are totally controlled, our strategy is hierarchical, since only the speed limit is provided, and vehicles still have to follow their leaders. Such a strategy is crucial for maintaining safety with mixed vehicles.     

Transportation network improvement and tolling strategies: The issue of intergeneration equity

Existing transportation network design studies focus on optimizing the network for a certain future time but without explicitly defining the time dimension within the formulation. This study extends the consideration by formulating the time-dependent network design problem. With this extension, one can plan for the optimal infrastructure improvement timetable, the associated financial arrangement, and tolling scheme over the planning horizon. In addition, this extension enables the pursuit of important considerations that are otherwise difficult, if at all possible, with the traditional timeless approach. Through the time-dependent framework, this study examines the issue of intergeneration equity according to the user and social perspectives. Basically, should the present generation build the full-blown network, or should users at the time pay for future incremental upgrades? Using a gap function to measure the degree of intergeneration equity achieved, this study illustrates that there are tradeoffs between societal and individual perspectives. Nevertheless, this study suggests ways whereby the planner can trade the level of equity to be attained with the overall network performance. In this way, some gradual measures can be introduced to the network design to compromise between these two perspectives.     

在用汽车尾气排放检测与维护(I/M)制度运行模式研究

本文开展了在用汽车尾气排放检测与维护(I/M)制度研究,分析了集中型、分散型、混合型等多种I/M制度运行模式的特点、优劣等方面,在此基础上,构建了I/M制度运行模式评价指标体系,并确定了评价方法及模型。本文研究成果及推广应用不仅对于引导、促进我国汽车尾气排放检测与维护(I/M)制度的实施,而且对于交通环境和空气质量的改善具有重要的意义。     

伦敦地铁隧道网的维护

当要全面考虑伦敦地铁的维护或将来的发展时,若对伦敦地铁历史(见附录)有个初步的了解将会是很有帮助的.这个系统的发展已经超过100年了,并且只是最近才改由一个独立的机构来管理.本文将部分地解释不同线间施工差异的复杂性.伦敦地下结构的大部分是地铁隧道,其中一些隧道自从在19世纪被建造以来还从来没有被完全评估过.当时,他们所使用的材料的物理性质和耐久性还不是完全地被人们所了解;如果这些隧道真是被"设计"的话,而且人们也只是按照经验来设计这些隧道的.当在1998年公私合营企业(PPP)刺激该程序最早开始实施的时候,隧道资产中的一些竖井和其它一些部分似乎已经被遗忘或丢失了.当前维护计划的一个主要部分就是确定需要维护和改善的大约178 km的地铁隧道资产现在所处的状况.     

The impact of competition on container port (in)efficiency

There are many studies on container port efficiency and that seek to understand what factors, such as technical and scale efficiency, private versus public terminal management or macro-economic factors, play on the efficiency score of a given port. There are fewer studies that focus on the role played by the inter-port competitive environment. This role remains difficult to assess. In fact, on the one hand, a port subject to high inter-port competition may record higher efficiency scores due to the pressure from the competitive environment. On the other hand, a port subject to high competition may be forced to over-invest and could therefore records a lower efficiency score. This article investigates this issue and examines how the degree of competition measured at different levels (local, regional and global level) impacts the efficiency score of a given container port. To do so, we implement a truncated regression with a parametric bootstrapping model. The model applied to information gathered for 200 container ports in 2007 and 2010 leads to the following conclusions: port efficiency decreases with competition intensity when measured in a range of 400–800 km (regional level); and the effect from competition is not significant when competition is measured at a local (less than 300 km) or at a global (more than 800 km) level. Estimates also show a tendency for ports who invested from 2007 to 2010 to experience a general decrease in efficiency scores, an element which could be explained by the time lag between the investment and the subsequent potential increase in container throughput.     

关于本刊定位和特约撰稿人申请事宜的信函往复

赵斌先生大鉴: 我是<运输经理世界>杂志执行主编陈致成.<关于应聘特约撰稿人的申请>传真信函并大作多篇均收悉,迟复为歉.