A Comparison of Alternative Obstacle Avoidance Strategies for Vehicle Control

In Alleyne (1996) several vehicle control options were considered for Unintended Roadway Departure (URD) prevention and conclusions were drawn as to the efficacy of each method. This companion paper investigates the use of several different inputs for the control of a vehicle, in the context of Obstacle Avoidance for autonomous vehicles. In this investigation, the goal of the controller is to provide an intervention in the event of the vehicle detecting an obstacle in its path. The five types of inputs that will be considered are (i) Four Wheel Steering; (ii) Front Wheel Steering; (iii) Four Wheel Brake Steering; (iv) Front Wheel Brake Steering; and (v) Rear Wheel Brake Steering. The controller design is an LQ controller based on the simplified dynamics of a 2 degree of freedom bicycle model. However, the analysis of the different strategies are performed on a more complete, nonlinear vehicle model. A key contribution of this paper is the quantitative evaluation of the relative efficiencies of each of these input strategies being examined. Unlike most control schemes, an important metric of performance is the ratio of peak tire force used versus available tire force. The conclusions reached in this paper shed additional light on appropriate input actuator methods for vehicle guidance and control.     

Applying cost—benefit analysis to marine safety measures

Cost-benefit analysis (CBA) provides a framework for consistent and rational decision-making. It can greatly assist the appraisal of marine safety and environmental measures, such as those recommended by the Donaldson Report. Combined with other techniques e.g. risk assessment, and noting the particular features of the maritime context, CBA is a valuable aid to thinking. The Department of Transport's emergency towing study is using it to weigh up the pros and cons of deploying tugs to protect the U.K. coast from oil and chemical pollution.     

New routes on old railways: increasing rail’s mode share within the constraints of the existing railway network

This paper describes an integrated methodology for identifying potential ‘quick wins’ for mode shift from road to passenger rail transport. Firstly, a procedure for analysing rail’s relative competitiveness in the market for passenger transport between large urban areas is developed and then applied to a UK case study. The purpose of such analysis is to allow the identification of flows where rail is currently relatively uncompetitive (in terms of journey time in particular) and to assess the reasons for this poor performance, so that the issues which suppress rail use may be addressed. In parallel, a framework, methodology and tool for the assessment of existing and potential capacity (trains, seats, TEUs, etc.) is developed for both passenger and freight traffic, to identify and address network constraints. An illustrative example of the use of these demand and capacity assessment tools is then presented, with the tools used to identify and evaluate flows where rail demand is suppressed by poor service quality and where spare capacity exists which would allow the passenger rail service to be improved without requiring significant investments in infrastructure. The effects of such improvements on demand are predicted, and the cost implications of operating such additional services are discussed. The analysis suggests that there may be significant potential for increasing rail’s mode share by providing additional inter-urban services where rail currently offers an inferior service.     

Extant Legal and Jurisdictional Constraints on Irish Coastal Management

The success of any coastal zone management policy is dependent on, among other things, effective legislation and its enforcement. This article examines some possible legal constraints on the implementation of an integrated coastal zone management policy in Ireland. An introduction to the existing legal framework is provided, and the inconsistencies and ambiguities related, in particular, to jurisdiction and area of responsibility are highlighted. In particular the effect of land ownership and property rights on coastal zone management are examined with reference to two popular resort beaches in County Donegal, Ireland. While a revision of the relevant legislation is desirable, it is probably unrealistic; however, powers are available to the various institutions involved in coastal management that are currently unused. These are reviewed and their potential to improve coastal zone management is discussed.     

The economics of railway safety

This paper reviews the statistics and economics of railway safety in Great Britain, the European Union and the United States, together with some results for Finland and Japan. In these countries railway safety has improved over recent decades. That finding applies both to train accidents and to personal accidents such as persons struck by trains. Fatal train collisions and derailments command most attention even though they are infrequent and account for only a small minority of railway fatalities. Great Britain, the EU and the USA formally espouse conventional cost benefit analysis for the appraisal of railway safety measures, using the same valuations for the prevention of casualties as are used in road safety appraisal. However there are often strong institutional, legal and political pressures towards adopting railway safety measures with safety benefit: cost ratios well below 1. The best-documented examples of this are automatic train protection systems, which are discussed in the paper. Apart from trespassers, the largest group of railway fatalities occur at level crossings, which the paper also discusses. Level crossing safety measures would seem to be an appropriate subject for cost benefit analysis, but there are few case-studies in the literature. Over the last few decades, the railways in many countries have been privatised or deregulated with the aim of improving their economic performance. Such changes have the potential to affect safety. The paper reviews evidence of the effects on safety of railway restructuring in Great Britain, Japan and the United State, and finds no evidence that safety deteriorated.     

Using ordered attitudinal indicators in a latent variable choice model: a study of the impact of security on rail travel behaviour

There is growing interest in the use of models that recognise the role of individuals’ attitudes and perceptions in choice behaviour. Rather than relying on simple linear approaches or a potentially bias-inducing deterministic approach based on incorporating stated attitudinal indicators directly in the choice model, researchers have recently recognised the latent nature of attitudes. The uptake of such latent attitude models in applied work has however been slow, while a number of overly simplistic assumptions are also commonly made. In this article, we present an application of jointly estimated attitudinal and choice models to a real-world transport study, looking at the role of latent attitudes in a rail travel context. Our results show the impact that concern with privacy, liberty and security, and distrust of business, technology and authority have on the desire for rail travel in the face of increased security measures, as well as for universal security checks. Alongside demonstrating the applicability of the model in applied work, we also address a number of theoretical issues. We first show the equivalence of two different normalisations discussed in the literature. Unlike many other latent attitude studies, we explicitly recognise the repeated choice nature of the data. Finally, the main methodological contribution comes in replacing the typically used continuous model for attitudinal response by an ordered logit structure which more correctly accounts for the ordinal nature of the indicators.     

ERTMS安全性研究--第六篇列车装载ERTMS(ETCS＆GSM-R)系统

欧洲铁路运输管理系统(ERTMS)由地面设备和车载设备组成.欧标司机室(Eurocab)是ERTMS车载设备的通称,包括:中心安全计算机(EVC)、与地面通信的设备(GSM-R)、人机界面设备(显示屏和控制盘, DMI)及与其他车载设备的接口(如制动、位置/速度检测设备等).     

Strategic management of organizational turnarounds in the transit industry

The traditional wisdom that there are increasing returns to scale among bus transit systems has been shaken with recent research findings. The implication from the literature is that unless many transit systems restructure along new organizational lines the financial and service provision difficulties will continue. Very few public transit systems have attempted to strategically manage change and turnaround organizationally.The objectives of this research were to identify the salient factors in organizational turnarounds and to determine whether these factors were evident within transit organizations that have attempted to manage change strategically. The author reviewed the corporate turnaround literature and conducted four case studies of strategic planning/management within the transit industry.All four cases exhibited organizational declines or perceived declines as imminent. They initiated turnarounds through reorganizations and efforts at strategic management. The reorganizations that occurred at all four cases were relatively minor, involving some changes in function. Only minor changes in management occurred and commitment to strategic management varied. Strategic objectives were not quantifiable. All of the cases could have improved their communication below the middle-management levels. The measures of performance in general did not relate a specific strategy and program to a particular turnaround effect. Through management commitment and some minor organizational restructuring two cases achieved some degree of turnaround. Total commitment to strategic management, organizational change, adequate communication, and accurate performance measures are keys to definitive turnarounds.