The basis of freeway surveillance and control systems is described in terms of 4 interrelated functional subsystems: driver, vehicle and roadway; surveillance and control input; central decision-making and control facilities; and surveillance and control outputs. Four tyes of ramp control are described in terms of control strategy, hardware, methodology and techniques, as well as function and utility of such control. Instances where ramp closure may be considered are set forth and details of fixed time metering control are outlined. The variations of traffic responsive metering control are: demand capacity control, gap acceptance control, occupancy control gap acceptance/demand capacity control, and demand-capacity/ occupancy control. The two moving merge control systems under experimentation are the pacer system and the green band system. The former consists of 3 elements, namely, a vehicle detection element (embedded loop detectors), control element (digital computer) and the driver communication element (traffic signs, traffic signals, and pacer light display, all located along the left shoulder of the ramp). A cost and benefit comparison is made of alternate ramp control systems.

  • Supplemental Notes:
    • Presented at Seminar W (Road Design 2: Specialist Topics) of the PTRC Summer Annual Meeting, Warwick University, England, 8-12 July 1974.
  • Corporate Authors:

    Planning and Transport Res and Computation Co Ltd

    167 Oxford Street
    London W1R 1AH,   England 
  • Authors:
    • Rottinghaus, B H
  • Publication Date: 1974-7

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00096303
  • Record Type: Publication
  • Report/Paper Numbers: PTRC/P/109
  • Files: TRIS
  • Created Date: Sep 10 1975 12:00AM