Advanced Transport Telematics Systems Research Articles

The Effects of Navigation Sensors and Spatial Road Network Data Quality on the Performance of Map Matching Algorithms

Map matching algorithms are utilised to support the navigation module of advanced transport telematics systems. The objective of this paper is to develop a framework to quantify the effects of spatial road network data and navigation sensor data on the performance of map matching algorithms. Three map matching algorithms are tested with different spatial road network data (map scale 1:1,250; 1:2,500 and 1:50,000) and navigation sensor data (global positioning system (GPS) and GPS augmented with deduced reckoning) in order to quantify their performance. The algorithms are applied to different road networks of varying complexity. The performance of the algorithms is then assessed for a suburban road network using high precision positioning data obtained from GPS carrier phase observables. The results show that there are considerable effects of spatial road network data on the performance of map matching algorithms. For an urban road network, the results suggest that both the quality of spatial road network data and the type of navigation system affect the link identification performance of map matching algorithms.

Urban road transport navigation: performance of the global positioning system after selective availability

Satellite navigation systems have a potential to support multi-modal transport navigation requirements. In road transport, the global positioning system (GPS) is currently supporting a wide variety of in-car navigation and transport telematics systems. The performance of GPS has in the past been limited by the artificial degradation of the signal through the process of selective availability (SA). With SA operational, the instantaneous horizontal positional accuracy was 100 m 95% of the time. Additional infrastructure was used with the differential concept (where range errors are determined at a known location and transmitted to users) to improve this to the level of a few metres. The US Government on 1 May 2000 removed SA. This paper presents the results of a study to assess and characterise the post-SA performance of GPS for positioning vehicles in urban areas. This is an important functionality of advanced transport telematics systems that aim to address everyday problems associated with road transport, particularly in urban areas. The performance assessment addresses, in varying levels of detail, the issues of service coverage, positioning accuracy, integrity and availability of service. Comparison is made with the results of a previous study conducted when SA was turned on. The results show an improvement in stand-alone navigation accuracy without SA compared to the period when SA was operational. Furthermore, no significant difference is seen between the level of accuracy achievable with differential positioning and post-SA stand-alone navigation. The parameters that characterise the performance of GPS determined at the analysis stage have been used to specify an architecture for a local navigation system for urban areas.

Impact of speech presentation level on cognitive task performance: implications for auditory display design

Speech displays and verbal response technologies are increasingly being used in complex, high workload environments that require the simultaneous performance of visual and manual tasks. Examples of such environments include the flight decks of modern aircraft, advanced transport telematics systems providing in-vehicle route guidance and navigational information and mobile communication equipment in emergency and public safety vehicles. Previous research has established an optimum range for speech intelligibility. However, the potential for variations in presentation levels within this range to affect attentional resources and cognitive processing of speech material has not been examined previously. Results of the current experimental investigation demonstrate that as presentation level increases within this ‘optimum’ range, participants in high workload situations make fewer sentence-processing errors and generally respond faster. Processing errors were more sensitive to changes in presentation level than were measures of reaction time. Implications of these findings are discussed in terms of their application for the design of speech communications displays in complex multi-task environments.

Deployment of interurban ATT test scenarios (DIATS): implications for the European road network

The paper summarizes the research results and implications from the DGVII-funded Fourth Framework research project Deployment of Interurban ATT Test Scenarios (DIATS). The objective of DIATS was to identify options available in the short and medium terms, for implementing advanced transport telematics (ATT) systems for motorway-type roads and to develop scenarios of 'highest potential impact' for each of the systems identified. Included are the results of a Delphi study into the most likely deployment scenarios for ATT technologies. The methodology developed to assess the organizational, social, environmental, efficiency, safety and legal concerns associated with new ATT systems is then described. This includes stated preference questionnaires, traffic simulation modelling, driver behaviour assessment using an instrumented vehicle, analysis of accident databases and literature reviews. A multicriteria analysis of the impacts of a range of ATT systems is then presented. In particular, the results discuss the potential impacts of new in-vehicle driver assistance devices such as adaptive cruise control on the operation and effectiveness of existing fixed-infrastructure systems. The paper concludes with a prioritized list of deployment strategies of maximum impact for all of the systems assessed. The research findings are already being applied nationally and a number of field trial assessments that will assist in this are also proposed.

Deployment of interurban ATT test scenarios (DIATS): Implications for the European road network

The paper summarizes the research results and implications from the DGVII-funded Fourth Framework research project Deployment of Interurban ATT Test Scenarios (DIATS). The objective of DIATS was to identify options available in the short and medium terms, for implementing advanced transport telematics (ATT) systems for motorway-type roads and to develop scenarios of 'highest potential impact' for each of the systems identified. Included are the results of a Delphi study into the most likely deployment scenarios for ATT technologies. The methodology developed to assess the organizational, social, environmental, efficiency, safety and legal concerns associated with new ATT systems is then described. This includes stated preference questionnaires, traffic simulation modelling, driver behaviour assessment using an instrumented vehicle, analysis of accident databases and literature reviews. A multicriteria analysis of the impacts of a range of ATT systems is then presented. In particular, the results discuss the potential impacts of new in-vehicle driver assistance devices such as adaptive cruise control on the operation and effectiveness of existing fixed-infrastructure systems. The paper concludes with a prioritized list of deployment strategies of maximum impact for all of the systems assessed. The research findings are already being applied nationally and a number of field trial assessments that will assist in this are also proposed.

Advanced Transport Telematics Positioning Requirements: An Assessment of GPS Performance in Greater London

This paper presents the results of a study carried out in the Greater London area to assess and characterise the performance of the Global Positioning System (GPS) for vehicle positioning in urban areas. The performance assessment addresses, in varying levels of detail, the issues of service coverage, positioning accuracy, integrity and availability of service. The project was supported by Racal Survey Limited and is part of the wider research at Imperial College in the area of architectural design and testing of Advanced Transport Telematics (ATT) systems. The results highlight the shortcomings of GPS as the sole means for in-car navigation in urban areas and details the temporal and spatial considerations to be taken into account in the process of designing an integrated positioning system capable of meeting navigation requirements placed on ATT systems.

Elderly and Disabled Travelers: Intelligent Transport Systems Designed for the 3rd Millennium

The TELematic Standards and Coordination of Advanced Transport Telematics systems in relation to elderly and disabled travelers (TELSCAN) project in the Transport Sector of the Telematics Applications Programme of the European Union has developed a Handbook of Design Guidelines (Nicolle & Burnett, 1999) to support designers of Intelligent Transport Systems (ITS) to include the needs of people who are elderly or disabled. This article describes the methods of the Handbook's development, including an overview of the methodology for capturing the requirements of elderly and disabled travelers, a survey of existing guidelines, and empirical results and lessons learned from simulator testing. The authors conclude that although general guidelines are necessary, the most specific and useful guidelines emerge only when carefully chosen research questions can be investigated. The development of such guidelines should help us come closer to achieving usability of ITS not only for elderly and disabled people, but for everybody as we enter the 3rd millennium.

Dynamic Behavioral Data Collection Using an Instrumented Vehicle

A significant problem that has become increasingly apparent in the development of models of driver behavior over the last few years is the absence of reliable data with which simulated processes, such as car following, may be compared. Obtaining such data, and the associated increase in model validity that this would allow, is clearly becoming of greater importance since a reliable baseline is required against which improvements in traffic flow and safety produced by many advanced transport telematics systems can be judged. One source of such data is an instrumented vehicle; a vehicle equipped with relative distance- and speed-measuring sensors that may be deployed in the traffic stream to collect data that are realistic, accurate, and dynamic. The opportunities for data collection afforded by instrumented vehicles are examined, in particular, the construction and testing of a new facility fitted with an optical speedometer, a radar rangefinder (capable of measuring the distance to, and relative speed of, the next vehicle in the traffic stream), and forward- and rear-looking video camera. Examples are given of the use of the vehicle in several current research projects, the operational strategies for which will be presented and discussed along with output. These include experiments on close-following, lane-changing, and the perception of relative speed. In conclusion, future areas of research and development are examined.

Advanced Transport Telematics System for Ports/The Piraeus Case

Abstract Aiming at enhancing the efficiency of transport systems and reducing the level of pollution,Advanced Transport Telematics(ATT) systems have been introduced, as they become feasible, due to rapid technological advances in computer systems, electronics and communications. The city of Piraeus was one of the initiators that used an integrated approach to traffic management and provision of travel and traffic information in order to improve the network efficiency and encourage the use of public transport. Information dissemination is planned to satisfy the requirements of travellers on board ferries and travellers approaching and leaving the port by car or public transport. The system architecture, the benefits, and the gained experience from the design and implementation of ATT systems for ports and especially the Piraeus case, are going to be presented in the paper.

Advanced Accessibility Systems for Elderly and Disabled Travellers in Canada

In Canada, as a result of the aging of the baby boom generation, the number of people 65 and older will nearly double by the year 2000. Since the rate of disability is highly correlated with aging, the number of Canadians with disabilities will likewise grow at a much faster rate than the general population. Of the disabled adult population, 62 percent (or 2 million) have difficulties using transportation services. The rapid developments in Intelligent VehicleHighway Systems (IVHS) in North America, or Advanced Transport Telematics Systems (AITS) in Europe, will be of great help to elderly and disabled travellers, including drivers, passengers, and pedestrians.It is strongly advocated in this paper that the requirements of these groups be integrated into the design of IVHS systems now, to avoid expensive and troublesome retrofits. The paper describes a conceptual framework for an advanced accessibility system developed by Canadian researchers to provide focus to this thrust, by linking it to existing IVHS modules, such as Advanced Traveller Information Systems (ATIS) and Advanced Public Transportation Systems (APTS), and to newly developed concepts like Advanced Mobile Support Systems (AMSS). An overview of Canadian activities in this area, with an emphasis on ergonomics evaluation, is presented.