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Intelligent Transport Systems, IET

Issue 3 • Date Sept. 2008

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Displaying Results 1 - 6 of 6
  • Review of traffic data estimations extracted from cellular networks

    Page(s): 179 - 192
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (605 KB)  

    One of the main characteristics of modern society is the never-ending increase in mobility. This leads to a series of problems such as congestion and increased pollution. To resolve these problems, it is imperative to have a good road network management and planning. To efficiently identify the characteristics of traffic in the road network, it would be necessary to perform a permanent monitorisation of all roadway links. This would involve an excessive cost of installation and maintenance of road infrastructure. Hence, new alternatives are required which can characterise traffic in a real time with good accuracy at an acceptable price. Mobile telephone systems are considered as a promising technology for the traffic data collection system. Its extensive use in converting its subscribers in a broad sample to draw information from phones becomes anonymous probes to monitor traffic. It is reviewed how to obtain parameters related to traffic from cellular-network-based data, describing methods used in existing simulation works as well as field tests in the academic and industrial field. View full abstract»

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  • The way ahead for London's bus priority at traffic signals

    Page(s): 193 - 200
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (251 KB)  

    London has a long history of successful schemes for bus priority at traffic signals. Recently, transport for London (TfL) has procured a modern automatic vehicle location (AVL) system for bus fleet management, passenger information and bus priority. The new system is known as iBUS and is based on Global Positioning System (GPS) and supporting technologies for bus location. The system eliminates the need for on-street hardware for detecting buses and provides more flexibility and opportunity for using bus detectors. However, bus location based on this system is less accurate than location based on fixed infrastructure (e.g. beacons) and could result in reduced benefits from bus priority. This paper first summarises how bus priority at traffic signals works within iBUS, and then explores the effects of GPS locational errors on bus priority benefits. This is followed by a discussion of opportunities available in the context of iBUS to build an even more efficient and beneficial bus priority system by taking advantage of its cost-effective multiple detection capabilities. The paper is based on various studies carried out by the Transportation Research Group (TRG) at the University of Southampton for TfL. View full abstract»

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  • Real-time pedestrian classification exploiting 2D and 3D information

    Page(s): 201 - 210
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (679 KB)  

    A new approach for standing and walking pedestrian detection using pattern matching and exploiting both 2D image information and 3D dense stereo information is proposed. Because 3D information accuracy does not allow the direct classification of the 3D shape, a combined 3D-2D method is proposed. The 3D data are used in an innovative way for pedestrian hypotheses generation, scale and depth estimation and 2D models selection. Also the 3D hypotheses allow the corresponding 2D image region of interest selection and the 2D hypothesis generation. The 2D hypothesis consists of the object-s external edges obtained by an edge extraction and a depth coherency-based filtering out process. The scaled models are matched against the selected hypothesis using an elastic high-speed matching based on the Chamfer distance. The method has been tested on synthetic and real-world scenarios. View full abstract»

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  • Planning feasible vehicle manoeuvres on highways

    Page(s): 211 - 218
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (326 KB)  

    The development of collision avoidance systems which are based on active intervention into the steering process is a promising way of reducing accident fatalities resulting from collisions with other road users. An important prerequisite of such systems is the calculation of feasible manoeuvres. In this paper, a sampling-based path-planning algorithm from robotics is proposed for planning trajectories on highways. In particular, adaptive polar splines are presented as one suitable way of describing path segments. Furthermore, it is demonstrated how kinematic constraints can be incorporated into the path-planning process. View full abstract»

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  • Route computation in large road networks: a hierarchical approach

    Page(s): 219 - 227
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (401 KB)  

    The optimal route between a given origin and destination needs to be computed in a fast and efficient manner in dynamic route guidance systems. Conventional routing algorithms have been found to be inadequate when applied directly to large road networks. Algorithms based on the concept of hierarchical abstraction make use of the knowledge about the road network to reduce search and provide near-optimal solutions. A generic procedure is presented for organising a given road network as a multiple-layer hierarchy. An efficient hierarchical routing algorithm is proposed, which breaks down the route search into a number of individual searches in small sub-networks. The algorithm incorporates a heuristic layer-switching technique to improve its performance without compromising the accuracy. The hierarchical routing algorithm was tested on the road network of Singapore and the solutions were found to be comparable to the optimal least-cost paths. View full abstract»

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  • Benchmarking travel time estimates

    Page(s): 228 - 237
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (752 KB)  

    Travel time estimates are widely regarded as the most practical information about traffic conditions available to individual drivers. Although there are numerous data collection and estimation methods in use today, few attempts have been made to evaluate them in a systematic manner. Even more fundamentally, there are no broadly accepted metrics to measure the quality of travel time estimates. The study exposes the methodology and tools employed to conduct a benchmark of travel time estimates in the San Francisco Bay Area. The methodology and the proposed quality measures are intended to set a standard that can be universally applied. Their use is illustrated through a sample data set collected for 24 h on one Bay Area freeway. 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.

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