AUTOMATIC FREEWAY SURVEILLANCE AND EVALUATION TECHNIQUES

A PILOT FREEWAY DETECTION SYSTEM WAS INSTALLED IN 1962, UNDER THE CHICAGO AREA EXPRESSWAY SURVEILLANCE PROJECT, WHICH HAS BEEN REFINED TO PROVIDE AUTOMATIC SURVEILLANCE, CONTROL, AND EVALUATION FOR A TOTAL OF 24 DIRECTIONAL MILES ON TWO CHICAGO AREA EXPRESSWAYS. CRITICAL SURVEILLANCE- EVALUATION DETECTORS TRANSMIT DATA OVER LEASED PHONE LINES TO A PROCESS-CONTROL COMPUTER IN THE PROJECT OFFICE. THE DIGITAL COMPUTER PROCESSES DETECTOR DATA INTO ON-LINE, REAL-TIME, FREEWAY SURVEILLANCE, ENTRANCE RAMP METERING CONTROL AND EVALUATION OUTPUTS. A DESCRIPTION IS GIVEN OF HOW THE ELECTRONIC SURVEILLANCE SYSTEM IS USED TO AUTOMATICALLY EVALUATE FREEWAY TRAFFIC OPERATIONS THROUGH EACH RUSH PERIOD. ON ONE AUTOMATIC TYPEWRITER, AN ON-LINE LANE OCCUPANCY PLOT IS DEVELOPED BY THE DIGITAL COMPUTER. ON THE SECOND AUTOMATIC TYPEWRITER, AN EXCESS VEHICLES PLOT IS DEVELOPED BY THE DIGITAL COMPUTER FROM A CLOSED SYSTEM OF FREEWAY AND RAMP DETECTORS. USING THE INPUT-OUTPUT TECHNIQUE OF COMPUTING SUBSYSTEM DENSITY CHANGES, THE EXCESS TOTAL TRAVEL TIME EXPERIENCED BY RUSH-PERIOD TRAFFIC IS DETERMINED. EXAMPLES ARE PRESENTED TO ILLUSTRATE THE EXTREMES OF RUSH PERIOD FREEWAY OPERATIONS, AS WELL AS ADDITIONAL REFINEMENTS IN THE PRINTOUT FORMAT.

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/hrr/1969/279/279-016.pdf
• Supplemental Notes:
  • Paper sponsored by Committee on Freeway Operations. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Authors:
  • McDermott, Joseph M
• Publication Date: 1969

Media Info

• Media Type: Print
• Pagination: p 158
• Monograph Title: Freeway traffic characteristics and control
• Serial:
  • Highway Research Record
  • Issue Number: 279
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Automatic control; Digital computers; Electronic control; Expressways; Freeway operations; Interchange ramps; Peak hour traffic; Traffic control; Traffic density; Traffic surveillance; Travel time; Vehicle detectors
• Old TRIS Terms: Freeway entrances and exits; Freeway ramps
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00225548
• Record Type: Publication
• Report/Paper Numbers: Paper No 1
• Files: TRIS, TRB
• Created Date: Oct 21 1994 12:00AM