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Intelligent Transport Systems, IET

Issue 2 • Date June 2009

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Displaying Results 1 - 15 of 15
  • Editorial

    Page(s): 103
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    Freely Available from IEEE
  • Epidemic algorithms for reliable and efficient information dissemination in vehicular

    Page(s): 104 - 110
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (290 KB)  

    Vehicular ad hoc networks (VANET), which are created by vehicles equipped with short- and medium-range wireless communication, have an array of important applications in intelligent transport systems. Many of these applications require reliable, bandwidth-efficient dissemination of traffic and road information via ad hoc network technology. This is a difficult task since inter-vehicular networks often lack continuous end-to-end connectivity and are characterised by large variations in node density. A new epidemic algorithm for information dissemination in highly dynamic and intermittently connected VANET is introduced. It is shown through realistic simulations in highway traffic that the proposed algorithm is capable of reliable and efficient information dissemination in VANET in the face of frequent network fragmentation and large density variations. View full abstract»

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  • Estimating the impact of abnormal loads on network performance

    Page(s): 111 - 123
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    The English Highways Agency is required to improve network performance including journey time reliability measured by average delay on the 10% slowest journeys along a specified set of primary routes in the strategic road network. Abnormal indivisible loads, which behave as moving bottlenecks, can cause significant delay, but the factors involved are complex, so methods have been developed to model their effect. These methods have been extended to estimate their impact through the Average Vehicle Delay (formerly PSA1 delay) measure, allowing mitigations through intelligent transportation system or policy options to be evaluated. Environmental impacts are also considered. View full abstract»

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  • Traveller information service based on real-time toll data in Austria

    Page(s): 124 - 137
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1570 KB)  

    The aim of this work is to demonstrate the suitability of existing toll collection data from the high-ranking road network in Austria for the generation of traffic information. The development of an area-wide, high-quality traffic information service in various implementations as prototypes was target of the project smart mobility analysis of real-time toll-data (GO-SMART). In order to achieve feasible travel time estimations detection and rejection of distorting data is essential. Several methods of outlier detection and filtering have been tested and compared. An algorithm exhibiting good attributes with regard to effectiveness, feasibility and performance has been designed and applied to the data. The developed method is adapted to the specific behaviour and features of the available data that are, among others, caused by system conditions of the tolling system. The proposed method is a combination of moving average, z-score and plausibility checks. For the purpose of displaying fast and up-to-date traffic information a weighted aggregation is suggested. Weights depend on timeliness and related vehicle type of single observations. In order to allow jam detection, a similar behaviour of observed vehicles (chargeable heavy good vehicles) and passenger cars is required in congested situations. This is necessary to assure the same behaviour of the measured part of the traffic (heavy good vehicles) and of the overall traffic. The required assumption could be reproduced for single velocity values as well as for approximation of density-velocity relations. Prototypes of pre-trip and on-trip traveller information services are presented. View full abstract»

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  • Truck adaptive following distance based on threat assessment under variable conditions

    Page(s): 138 - 147
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (297 KB)  

    Vehicle-stopping distance and recommended following distance are important factors for heavy-duty truck safety. The practical vehicle stopping-distance is affected by several factors beside vehicle dynamics: current speed, braking system retardation force, road slip and road grade. One of the purposes of truck onboard monitoring is to provide real-time feedback to the driver that could have two forms: a warning to the driver for any threat of frontal collision; or advisory information. Both are based on threat assessment and thus are equivalent in theory. Most previous work in the literature only provides threat assessment and warning under ideal cases that is, flat, straight, dry and concrete road surface conditions. The authors systematically investigate vehicle stopping distance under variable conditions, based on which the corresponding recommended following distance is generated. Although it is difficult for the driver to estimate the following distance visually, sensor detection plus appropriate feedback to the driver can achieve the same goal. Practical implementation issues and field test results are also presented. They show how significantly the environmental factors affect the threat assessment and the recommended following distance. The results are readily applicable to the development of safety systems for other types of vehicles. View full abstract»

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  • Robust mobility adaptive clustering scheme with support for geographic routing for vehicular ad hoc networks

    Page(s): 148 - 158
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (482 KB)  

    There are a number of critical problems related to road safety in intelligent transportation systems (ITS) caused by increased vehicle usage, urbanisation, population growth and density, and faster rates of movements of goods and people. It is envisaged that vehicular ad hoc networks (VANETs) will bring about a substantial change to the way our road transport operates to improving road safety and traffic congestion. A major challenge in VANETs is to provide real-time transfer of information between vehicles within a highly mobile environment. The authors propose a new clustering scheme named robust mobility adaptive clustering (RMAC) to strategically enable and manage highly dynamic VANETs for future ITS. It employs a novel node precedence algorithm to adaptively identify the nearby 1-hop neighbours and select optimal clusterheads based on relative node mobility metrics of speed, locations and direction of travel. Furthermore, the zone of interest concept is introduced for optimised approach to the network structure such that each vehicular node maintains a neighbour table of nodes, beyond its communications range, that reflects the frequent changes on the network and provides prior knowledge of neighbours as they travel into new neighbourhoods. RMAC predominantly employs more reliable unicast control packets and supports geographic routing by providing accurate neighbour information crucial when making routing decisions in multi-hop geographic routing. It is shown by simulations that RMAC on IEEE802.11 ad hoc WLAN protocol is very effective in a highly dynamic VANETs environment, being robust on link failures, and having very high cluster residence times compared to the well known distributed mobility clustering scheme. View full abstract»

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  • Spatial econometrics models for congestion prediction with in-vehicle route guidance

    Page(s): 159 - 167
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (438 KB)  

    The congestion dependence relationship among links using microsimulation is explored, based on data from a real road network. The work is motivated by recent innovations to improve the reliability of dynamic route guidance (DRG) systems. The reliability of DRG systems can be significantly enhanced by adding a function to predict the congestion in the road network. The application of spatial econometrics modelling to congestion prediction is also explored, by using historical traffic message channel (TMC) data stored in the vehicle navigation unit. The nature of TMC data is in the form of a time series of geo-referenced congestion warning messages, which is generally collected from various traffic sources. The prediction of future congestion could be based on the previous year of TMC data. Synthetic TMC data generated by microscopic traffic simulation for the network of Coventry are used in this study. The feasibility of using spatial econometrics modelling techniques to predict congestion is explored. The results are presented at the end. View full abstract»

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  • Planning and implementing field operational tests of intelligent transport systems: a checklist derived from the EC FESTA project

    Page(s): 168 - 184
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (194 KB)  

    To date, the main focus of intelligent transport systems (ITS) research programmes has been on technology development and proof of concept, rather than on understanding the implications of system implementation. Improved knowledge is needed about the ways in which drivers use ITS, their short- and long-term effects and how system performance can be optimised. The field operational test, or FOT, is a sophisticated evaluation method that can be used to answer these and other critical questions, and to stimulate market acceptance and demand for ITS. Although the large-scale FOTs conducted to date have yielded important insights into both the positive and potentially negative impacts of ITS, there is considerable scope for improving the design and implementation of FOTs. There are many advantages in doing so. The authors outline, in the form of a checklist, the critical steps and considerations involved in successfully planning and implementing an FOT, drawing on work undertaken in the EC-funded FESTA (Field opErational TeSt support Action) project. View full abstract»

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  • IET Road Pricing 2008 Conference, London, 9-10 Dec 2008

    Page(s): 185 - 187
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    Freely Available from IEEE
  • Intelligent transportation systems: a safe, robust and comfortable strategy for longitudinal monitoring

    Page(s): 188 - 197
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (515 KB)  

    An original non-cooperative longitudinal control strategy, based on a new, non-linear and second-order reference model, is studied. The control strategy yields analytical dynamic solutions and pays extreme care to safety constraints. It lowers the safe inter-vehicular distance and is also robust towards errors of sensors when measuring the speed of obstacles. This robustness, valid for slow-moving obstacles as well as fast-moving ones, is a decisive benefit of this strategy. The strategy consists of two main phases depending on vehicles relative interdistance. Considering acceleration and jerk (time derivative of acceleration) as comfort metrics, it is also shown that the control strategy proves comfortable. Simulation results validate the control strategy. View full abstract»

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  • Detection of incidents and events in urban networks

    Page(s): 198 - 205
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    Events and incidents are relatively rare, but they often have a negative impact on traffic. Reliable travel demand predictions during events and incident detection algorithms are thus essential. The authors study link flows that were collected throughout the Dutch city of Almelo. We show that reliable, event-related demand forecasting is possible, but predictions can be improved if exact start and end times of events are known, and demand variations are monitored conscientiously. For incident detection, we adopt a method that is based on the detection of outliers. Our algorithm detects most outliers, while the fraction of detections due to noisy data is only a few percent. Although our method is less suitable for automatic incident detection, it can be used in an urban warning system that alerts managers in case of a possible incident. It also enables us to study incidents off-line. In doing so, we find that a significant fraction of traffic changes route during an incident. View full abstract»

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  • Intelligent vehicle clusters (Inside Com2React project)

    Page(s): 206 - 215
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    The intelligent vehicle clusters concept has been introduced and developed in the Com2React project to overcome some of the limitations of the former REACT research project. Cluster of vehicles together with the regional control center constitute a hierarchical traffic information and communication structure where vehicles on the local level are mainly self-organised but then additionally controlled by the traffic management system on the regional level. The main challenge was to secure the achievements and benefits of the REACT applications and to find a new balance for efficient data processing, communication and utilisation between the different entities in the overall system. The aim here is to give a brief review and analysis of the most important features and benefits of this concept. View full abstract»

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  • Developing value networks for I2V co-operative services: An Austrian example

    Page(s): 216 - 224
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    COOPERS, an EC FP6 funded IP, deals with co-operative systems, enabling the communication of real-time data between infrastructure and vehicle, based on the development of an innovative telematics application. The main objective of this undertaking is to increase road safety and road efficiency. Value chain activities and the building of an appropriate business model are key elements in the project itself and for the business development of future COOPERS services. This paper shows the main actors for a value network in the co-operative systems context. It reveals that besides traditional roles, such as content provider, application provider, service provider and data distributor, new roles, such as the role of a data clearance entity, are also needed. In the example analysed in this paper, a differentiation is made between a value network for safety-critical services and convenience services. In the safety-critical services case a traffic control centre plays the leading role, whereas in the case of the convenience services a Telco takes over the lead. View full abstract»

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  • Assessing the effects of inter-vehicle communication systems on road safety

    Page(s): 225 - 235
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    The work described assesses the impact of inter-vehicle communication systems on road safety. A simple model is used to assess the reduction in accident risk if the response time of drivers is improved by state of the art technology. The currently available techniques for inter-vehicle communication, based either on direct communication between vehicles or on vehicle-to-infrastructure and vice versa, are briefly examined in order to provide an overview of the recent proposals the world of electronics and telecommunications has made available to the transport industry concerning safety. A method to assess safety, based on a parameter called risk index (RI), is then proposed in order to evaluate to what extent the use of vehicle-to-vehicle and vehicle-to-infrastructure communication technologies can actually increase road safety. View full abstract»

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  • Safe airport operation based on innovative magnetic detector system

    Page(s): 236 - 244
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (566 KB)  

    A novel magnetic sensing technology that forms the basis of an innovative system to monitor ground vehicle movements at airports is presented. The operating principle of this system is the detection of interaction of aircraft or ground vehicles with the earth's magnetic field using sensitive magnetic field detectors. After development and laboratory testing of the detectors, test sites have been set up at three European airports. Potential applications of the detectors were designed and demonstrated. Tests have shown that the system can be applied for ground movement surveillance. The approach can be used as a complementary surveillance system for existing and future advanced surface movement guidance and control systems (A-SMGCS) at large airports or as a cost-effective stand-alone solution for monitoring critical areas at medium and small airports. Furthermore, this system can be applied as well in road traffic and car park occupancy monitoring. Unaffected by weather conditions, interference and shadowing effects, the system provides reliable vehicle position, velocity and direction information without requiring any equipment in aircraft or ground vehicles and thus it increases airport operational safety. View full abstract»

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Aims & Scope

IET Intelligent Transport Systems is an interdisciplinary journal devoted to research into the practical applications of intelligent transport systems and infrastructures.

Full Aims & Scope

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IET Research Journals
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