No longer in the driver’s seat: How do affective motivations impact consumer interest in automated vehicles?

Transportation - Emerging advancements in automated vehicles may dramatically change how transportation system users engage cars as symbols and tools to exert control over their lives, time use,...     

Enhanced selective forwarding scheme for alert message propagation in vehicular <Emphasis Type="Italic">ad hoc</Emphasis> networks

Vehicle-based applications were recently introduced to improve traffic safety and efficiency. These applications are classified into either safety-oriented or non-safety-oriented applications. Safety-oriented applications are typically provided by means of vehicle-to-vehicle (V2V) communications to support reliable and fast alert message propagation to all surrounding vehicles when an emergency occurs on the road. In vehicular ad-hoc network (VANET) broadcast-based packet forwarding is typically preferred for the propagation of urgent traffic-related information to all reachable nodes within a specified dangerous region. However, this approach may cause broadcast storm problems, which can lead to serious contention between transmissions from adjacent nodes. In this paper, we propose an alert message propagation scheme that is based on selective forwarding and aims to i) minimize the number of rebroadcasting nodes and ii) guarantee reliable and fast alert message delivery to all reachable nodes. Our scheme was evaluated using two different highway scenarios. The simulation results demonstrated that the performance of the proposed scheme was better than that of existing broadcast schemes in terms of the message delivery latency, the message delivery ratio, and the message rebroadcasting ratio.     

Route Choice Models Used in the Stochastic User Equilibrium Problem: A Review

Several route choice models are reviewed in the context of the stochastic user equilibrium problem. The traffic assignment problem has been extensively studied in the literature. Several models were developed focusing mainly on the solution of the link flow pattern for congested urban areas. The behavioural assumption governing route choice, which is the essential part of any traffic assignment model, received relatively much less attention. The core of any traffic assignment method is the route choice model. In the wellknown deterministic case, a simple choice model is assumed in which drivers choose their best route. The assumption of perfect knowledge of travel costs has been long considered inadequate to explain travel behaviour. Consequently, probabilistic route choice models were developed in which drivers were assumed to minimize their perceived costs given a set of routes. The objective of the paper is to review the different route choice models used to solve the traffic assignment problem. Focus is on the different model structures. The paper connects some of the route choice models proposed long ago, such as the logit and probit models, with recently developed models. It discusses several extensions to the simple logit model, as well as the choice set generation problem and the incorporation of the models in the assignment problem.     

Financial appraisals of a microcomputer‐based referencing system for a local bus travel telephone enquiry service

Abstract

Solution of current and future transportation problems requires a more consistent and complete realization of the principles of socioeconomic motivation in research and practical work. With this aim it is suggested that a transport‐communication model (TCM) of society should be constructed as a projection of all the social processes into the space of artificial flows of matter, energy and information. A simplified example of a transport‐communication systems model in terms of mathematical systems theory is reviewed, demonstrating the constructs of such an approach, and a critical analysis is made of scientific paradigms, used in the transportation theory. The author suggests an iterative procedure for the formation of a hierarchic theory of transportation systems based on simulation concepts and experiments, and formulates a hypothesis of its feasibility in the construction of present‐day transportation theory as a realistic basis for solving transportation problems.     

Railway planning in developing countries: a case study of Colombia

This paper describes a study of possible network changes for the Colombian railway system. A cost model is developed and the variation of costs with traffic density and with gradient is analysed and found to be different from that expected from experience in developed countries. The evaluation of network changes is carried out by a form of systems analysis in which two new lines and many closures are examined. Closures are evaluated by means of social cost benefit analysis incorporating a consumers’ surplus approach. The study recommends fairly radical changes to the present network configuration, these involving the construction of one new line and the closure of several existing ones.     

Analysis of the evolvement of contact wire wear irregularity in railway catenary based on historical data

This paper studies the evolvement of the wear irregularity of contact wire using wire thickness data measured yearly from a section of railway catenary. The power spectral density and time–frequency representation based on the wavelet transform are employed for data analysis, with an emphasis on local wear irregularities that are crucial for contact wire condition assessment. To investigate the cause of wear irregularity evolvement and the mutual influence with the pantograph–catenary dynamic interaction, simulations considering the influence of wear irregularity are carried out based on the finite element method. Analyses of the actual wear irregularities and the dynamic contact force under singular and complex wear irregularities are performed. Although the wear irregularity has limited impact on the pantograph–catenary interaction, it can induce the vibration of pantograph and contact wire that will lead to a notable increase of contact force standard deviation. The evolvement of wear irregularity is closely associated with the span length and dropper distribution of catenary structure and the running direction of pantograph. In addition, it is found feasible to detect the wear irregularity based on contact force, on condition that the sampling frequency is high enough to reflect the indicative frequencies.     

Experimental Study of System Optimization for Suppression of Vehicle Vibration

The improvements of ride comfort and vehicle maneuverability in the vehicle design can be achieved by using an active suspension. However, the problems in such a control are the complex control logic because of the control laws incompatible with the improvements of ride comfort and maneuverability, and the cost increase because of various sensors to be attached. Therefore, we examined the control abilities of ride comfort and maneuverability on a unique control law using frequency shaped LQ, and controlled the characteristic of the contact between tire and road without a road displacement sensor     

How much do people value the environment?

The selection and evaluation of road schemes through the Leitch framework is based on a combination of cost-benefit analysis and environmental impact assessment. Both techniques involve the definition and valuation of a number of costs and benefits. These costs and benefits are defined and valued in isolation to each other so that we know virtually nothing about the relative valuation that people assign to different types of costs and benefits which might affect them directly or indirectly. This paper outlines the development of a method which allows people to conceptualise the costs and benefits of a road scheme in their own terms and then to rank schemes in relation to those costs and benefits. This method is based upon an interview process involving the use of repertory grid technique. The information from the repertory grid technique is used as a sound basis for determining trade-offs between attributes and for attempting to obtain monetary valuations of different project attributes. A number of exploratory interviews are reported which outline some of the difficulties with a number of the survey features including the choice of case-study, interviewer and information biases and sample and non-response biases. Various ways of dealing with these difficulties are discussed.     

Cost-based approach for sizing of pedestrian facilities

Pedestrian facility size is currently determined in direct relationship to the design level of service. However, the design level of service is chosen arbitrarily from the six levels of service, which are assumed to represent the freedom available for movement at different levels of pedestrian flow. This direct and simple approach to facility sizing is shown to have two fundamental deficiencies that contribute to wasteful over capacity. In this article, a cost-based approach is introduced to overcome the deficiencies. Two analytical models, one for determining optimal design density and another for determining optimal design flow, are presented. The optimum design parameters minimize the total cost of the facility defined as the sum of construction cost and user cost. The sensitivity of the optimum parameters to the cost and pedestrian flow parameters is demonstrated using a numerical example.