THE SCOOT ON-LINE TRAFFIC SIGNAL OPTIMISATION TECHNIQUE

Many large cities have, or plan to have, urban traffic control (utc) systems that centrally monitor and control the traffic signals in their jurisdiction. The present generation of utc systems usually co-ordinates the signals on fixed-time plans, which consist of sets of timings that determine when each signal turns red and green. The plans are precalculated to suit average conditions during each part off the day (e.g. A.M. peak) and do not respond to variations in flows in the network. Since 1973 the UK Transport and Road Research Laboratory has been researching a vehicle responsive method of signal control called SCOOT (split, cycle and offset optimisation technique). Research was carried out in Glasgow by a small team from TRRL and the Ferranti, GEC and Plessey traffic companies, with assistance from Strathclyde Regional Council. In 1976 the success of the research phase led to a development project between the departments of transport and of industry and the three traffic companies. TRRL continued research into SCOOT and in 1979 carried out a full-scale trial of SCOOT in Glasgow. As part of the development project, and with the co-operation of West Midlands County Council, SCOOT was installed in Coventry. A further full-scale trial of the developed system was carried out in 1980. This paper describes the SCOOT system and the results of the trials which compared SCOOT with up-to-date fixed-time systems. It is concluded that SCOOT reduced vehicle delay by an average of about 12 percent during the working day. The surveys demonstrate that scoot rapidly adapts to unusual traffic conditions as well as to the usual variations in demand that occur throughout the day and night. It is an important benefit of SCOOT that there is no need to periodically prepare new fixed-time plans and that the signal timings are automatically kept up-to-date. The traffic model in SCOOT provides real-time information on flows and queues and is likely to be a key element in the development of new traffic management strategies that make the best overall use of roads in urban areas. This paper is a shortened version of TRRL Report LR 1014 (see TRIS 348845). This paper was presented at the IEE's Conference on Road Traffic signalling, Londong, March 1982. See also TRIS abstracts 368871 and 368872. (TRRL)

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    Printerhall Limited

    29 Newmart Street
    London W1P 3PE,   England 
  • Authors:
    • HUNT, P B
    • ROBERTSON, D I
    • BRETHERTON, R D
    • ROYLE, M C
  • Publication Date: 1982-4

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  • Accession Number: 00368870
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Jan 31 1983 12:00AM