GRAPHICAL REPRESENTATION OF THE EFFECT OF SIGNAL TIMINGS ON DELAY AT 2-STAGE JUNCTIONS USING COMPUTER GRAPHICS

Allsop (1971) has shown that if delay at a road junction controlled by fixed-time traffic signals is estimated by the simpler form of Webster's expression (1958), the calculations of delay-minimising signal settings can be expressed as a mathematical optimisation problem having a unique solution (Allsop, 1972). In calculating the signal settings, a maximum can be specified for the lengths of time for which particular sets of traffic streams have right of way. These are the constraints which often have to be imposed on signal settings. In simple cases the constraints imposed can be represented diagrammatically, and the way in which the estimated delay per unit time to all the traffic passing through the junction varies with the signal timings can be shown in the same diagram. The minimum-delay and maximum-capacity points can also be included. Within this framework the paper describes the process of working out the above mentioned diagrams orientated to develop a computer program with graphics capabilities which enable the user, in an interactive way, to draw the diagrams. A review and summary of the mathematics, the basis for the algorithms, an example and finally an indication of scope for future work are presented in the paper. For the covering abstract of the seminar see TRIS 450556. (Author/TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/086050137X
• Supplemental Notes:
  • Proceedings of Seminar L, Traffic Operation and Management; Held at the 12th PTRC Summer Annual Meeting, University of Warwick, England, From 10-13 July 1984, Volume P, 254.
• Corporate Authors:

  PTRC Education and Research Services Limited

  110 Strand
  London WC2,   England 
• Authors:
  • SAAVEDRA, A
• Conference:
  • Planning & Transport Res & Comp, Sum Ann Mtg, Proc
• Publication Date: 1984

Media Info

• Features: Figures; References;
• Pagination: p. 217-237

Subject/Index Terms

• TRT Terms: Algorithms; Charts; Computer graphics; Computer programs; Conferences; Digital computers; Highway capacity; Intersections; Mathematical models; Minimization; Optimization; Simulation; Traffic control; Traffic delays; Traffic signal cycle; Traffic signal timing; Traffic signals
• Uncontrolled Terms: Interactive graphics; Interactive models; Minimum; Optimum
• ITRD Terms: 643: Capacity (road, footway); 6486: Chart; 8525: Conference; 576: Cycle (traffic signals); 9010: Delay; 8673: Digital computer; 6462: Interactive model; 455: Junction; 6473: Mathematical model; 9046: Minimum; 8645: Software; 654: Traffic control; 565: Traffic signal
• Subject Areas: Highways; Operations and Traffic Management; I71: Traffic Theory; I73: Traffic Control;

Filing Info

• Accession Number: 00450580
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• ISBN: 086050-137-X
• Files: ITRD, TRIS
• Created Date: Aug 27 2004 9:56PM