车辆安全和联合国十年行动计划

预计到2030年道路交通事故将成为第五大致命原因，每年死亡人数将上升至240万人。儿童、青少年和自行车、摩托车车手以及行人这类易受碰撞的群体是最处于危险之中的。     

A method to assess demand growth vulnerability of travel times on road network links

Many national governments around the world have turned their recent focus to monitoring the actual reliability of their road networks. In parallel there have been major research efforts aimed at developing modelling approaches for predicting the potential vulnerability of such networks, and in forecasting the future impact of any mitigating actions. In practice—whether monitoring the past or planning for the future—a confounding factor may arise, namely the potential for systematic growth in demand over a period of years. As this growth occurs the networks will operate in a regime closer to capacity, in which they are more sensitive to any variation in flow or capacity. Such growth will be partially an explanation for trends observed in historic data, and it will have an impact in forecasting too, where we can interpret this as implying that the networks are vulnerable to demand growth. This fact is not reflected in current vulnerability methods which focus almost exclusively on vulnerability to loss in capacity. In the paper, a simple, moment-based method is developed to separate out this effect of demand growth on the distribution of travel times on a network link, the aim being to develop a simple, tractable, analytic method for medium-term planning applications. Thus the impact of demand growth on the mean, variance and skewness in travel times may be isolated. For given critical changes in these summary measures, we are thus able to identify what (location-specific) level of demand growth would cause these critical values to be exceeded, and this level is referred to as Demand Growth Reliability Vulnerability (DGRV). Computing the DGRV index for each link of a network also allows the planner to identify the most vulnerable locations, in terms of their ability to accommodate growth in demand. Numerical examples are used to illustrate the principles and computation of the DGRV measure.     

Derivation of delays based on improved macroscopic traffic models

Recent improved and rigorous mathematical models describing the formation and dissipation of queues at signalized intersections are employed for deriving delay and effective queue size. Analytical and numerical solutions are presented that are applicable for both isolated and coordinated intersections. Comparisons against results obtained from conventional models reveals significant differences. Further, it is demonstrated that the current practice of calculating delays from input-output analysis results in substantial overestimation of delays. Numerical examples supporting this finding are presented.     

Formulating and solving the network design problem by decomposition

The optimal transportation network design problem is formulated as a convex nonlinear programming problem and a solution method based on standard traffic assignment algorithms is presented. The technique can deal with network improvements which introduce new links, which increase the capacity of existing links, or which decrease the free-flow (uncongested) travel time on existing links (with or without simultaneously increasing link capacity). Preliminary computational experience with the method demonstrates that it is capable of solving very large problems with reasonable amounts of computer time.     

Air pollution impact of maritime shipping operations in the port of Houston

Abstract

Major air pollutants from maritime shipping operations are sulfur oxides, nitrogen oxides, and particulate matter emissions from combustion of fuel oil during cruise, berth, and start‐up modes. Sulfur oxides emissions are substantial from steamships burning high‐sulfur residual fuel oil, where shipping contributes 66 percent of the total sulfur dioxide emissions from transportation sources, and almost 3 percent of the total for Harris county, Texas. Nitrogen oxides emissions are significant during cruise conditions for both steamships and motor ships, while particulate emissions are substantial during start‐up and tube cleaning.

Significant marine air pollutant emission sources are found in busy harbor areas such as the Houston Ship Channel. Offshore terminals for unloading large tankers may result in emissions of 10 to 20 tons of sulfur oxides daily per ship, and 3 to 5 tons of nitrogen oxides daily per ship during pumping operations. Trace‐metal constituents present in the oil may catalyze sulfur dioxide and nitrogen dioxide oxidation to their respective sulfate and nitrate aerosols in the humid Texas Gulf Coast atmospheres to aggravate photochemical air pollution problems once the air masses reach industrial and populated urban areas on land. Onshore sulfur dioxide and particulate‐matter emission controls may be necessary for some large ships in port to minimize potential impact on coastal zone air quality.     

Noise,vibration, harshness model of a rotating tyre

ABSTRACT

The tyre plays a fundamental role in the generation of acoustically perceptible driving noise and vibrations inside the vehicle. An essential part of these vibrations is induced by the road excitation and transferred via the tyre into the vehicle. There are two basic ways to study noise, vibration, harshness (NVH) behaviour: Simulations in time and frequency domains. Modelling the tyre transfer behaviour in frequency domain requires special attention to the rotation of the tyre. This paper shows the approach taken by the authors to include the transfer behaviour in the frequency range up to 250?Hz from geometric road excitations to resulting spindle forces in frequency domain. This paper validates the derived NVH tyre model by comparison with appropriate transient simulations of the base transient model.     

Book reviews

THE U.S. AIRFREIGHT INDUSTRY, by Nawal K. Taneja. Lexington Books, Lexington, Mass., 1979. 244 pp.

TRAFFIC, OPERATIONAL RESEARCH, FUTUROLOGY, by Arne Jensen. North Holland Publishing Company, Amsterdam, 1980. 321 pp. ($39.00)

PROBLEMS OF THE CARLESS, by R. E. Paaswell and W. W. Recker. Praeger Publishers, New York, 1978. 190 pp.

TRANSPORTATION AND THE ELDERLY, by Martin Wachs. University of California Press, Berkeley, 1980.

PUBLIC TRANSPORTATION: PLANNING, OPERATIONS AND MANAGEMENT, edited by George E. Gray and Lester A Hoel. Prentice Hall, Englewood Cliffs, New Jersey, 1979. 749 pp.

ETHYL ALCOHOL PRODUCTION AND USE AS A MOTOR FUEL, edited by J. K. Paul. Noyes Data Corporation, New Jersy, 1979. 354 pp ($48.00).

URBAN PLANNING AND PUBLIC TRANSPORT, edited by Roy Cresswell. The Construction Press, London, 1980. 172 pp. (£15.00)     

Effectiveness of ECE R66 and FMVSS 220 standards in rollover crashworthiness assessment of paratransit buses

The main objective of the presented study was to compare the effectiveness of two standard test procedures for evaluating bus roof integrity: the dynamic rollover test according to UN-ECE Regulation 66 (ECE-R66), and the quasi-static symmetric roof loading according the Federal Motor Vehicle Safety Standard 220 (FMVSS 220). Both tests were applied to a selected Paratransit Bus. The investigation was carried out primarily using a numerical study backed up by experimental validation tests on components and full scale rollover tests. A sensitivity analysis using LS-OPT? was performed to identify the most important structural components influencing the response of the bus in these two tests. The results obtained from this study show that the final outcome of the crashworthiness assessment of the selected paratransit bus depends on the selection of the evaluation standard. Although the two tests are used for the same purpose of roof integrity evaluation, their results are divergent and may lead to different conclusions. The paper presents a discussion on the effectiveness of both standards in evaluating the rollover crashworthiness.     

Maritime policy and management--30 years issue for Prof. James McConville Editorial: IMO--The economics of intimidation

Organizational Effectiveness (OE) is a rather new concept in the port business literature and not widely studied before. From the systems perspective, this concept focuses on the goals of the organization, the resources needed to achieve these goals, and the relationship between the organization and its environment. The reason behind choosing a systems approach is the significant role of seaports as open systems affected by changes and developments in world trade, supply chain and logistics trends, maritime transport, and technological developments. While seaports are multi-faceted organizations that constitute different interdependent and integrated units in their structure, they can also be regarded as the subsystems of the supply chain system. As being the social and technical systems, port organizations have unique characteristics that should be examined in detail to assess their effectiveness. To assess the effectiveness of port organizations, principally a set of effectiveness measures applicable to seaports should be determined. The main aim of this study is to assess the relative importance of the main effectiveness criteria in seaports and to determine the significance of main inputs and port subsystems which can be referred as the means to achieve effectiveness. By using the systems approach, the inputs, the processes, and the outputs of the port organizations are clearly defined with a conceptual model. Thirty-three statements have been developed under the main categories in the systems model and a two-round delphi survey is conducted, and qualitative analysis of the experts’ opinions is carried out. The results of the delphi survey show that the main port inputs are port infrastructure, equipments, technology, and port labor; the major port processes are ship and cargo operations together with the logistics services, safety and security, information technologies, and marketing; and the most important effectiveness measures for the seaports are productivity, efficiency, service quality, adaptability, information and communication management, profitability, human resource quality, and customer satisfaction.