FREEWAY OPERATIONS ON THE GULF FREEWAY RAMP CONTROL SYSTEM

THE GULF FREEWAY SURVEILLANCE AND CONTROL PROJECT IS DESCRIBED AS IT OPERATED IN 1969. THE EQUIPMENT CONFIGURATION, CONTROL STRATEGY USED, AND OPERATIONAL MEASURES OF EFFECTIVENESS ARE PRESENTED AND COMPARED TO "BEFORE CONTROL" CONDITIONS. FOLLOWING ARE SOME OF THE SIGNIFICANT RESULTS OF CONTROL: (1) TOTAL TRAVEL INCREASED BY 10% DURING 6:30-8:30 AM PERIOD AND 16% DURING 7:00-8:00 AM PERIOD; (2) AVERAGE SPEED DURING CONTROL PERIOD INCREASED 12.2 MPH TO 32.6 MPH; (3) ACCIDENTS DURING CONTROL DECREASED 27%; AND (4) VIOLATION OF RAMP SIGNALS RANGED FROM 1% TO 13%. /AUTHOR/ THE BASIS OF MAXIMIZING THE TOTAL NUMBER OF VEHICLES SERVED, AND ALSO BALANCING THE ENTRANCE RAMP QUEUES. THE OPTIMAL STEADY-STATE COMPONENTS ARE SELECTED BY QUADRATIC PROGRAMMING. FOR ANY GIVEN VECTOR FO THESE COMPONENTS, THERE CORRESPONDS A VECTOR OF STEADY STATE DENSITIES ALONG THE FREEWAY. A LOCAL LINEARIZATION OF THE FREEWAY MODEL IS PERFORMED ABOUT THIS REFERENCE VECTOR OF DENSITIES. THE TIME-VARYING COMPONENT OF THE ENTRANCE RAMP RATES IS DETERMINED USING STANDARD STATE REGULATOR TECHNIQUES BASED ON THE LINEARIZED MODEL AND A QUADRATIC PERFORMANCE FUNCTIONAL OF DEVIATIONS FROM THE STEADY-STATE DENSITIES AND ENTRANCE-RAMP RATES. SEVERAL SIMULATION EXAMPLES ILLUSTRATE THE SUPERIORITY OF THE CONTROL ALGORITHM OVER NO CONTROL AND RAMP METERING BASED ONLY ON LOCAL INFORMATION ABOUT THE STATE OF THE SYSTEM. /AUTHOR/

• Supplemental Notes:
  • Rr 24-25, 27 PP, 12 FIG, 11 TAB
• Corporate Authors:

  Texas Transportation Institute

  Texas A&M University System, 1600 E Lamar Boulevard
  Arlington, TX  United States  76011

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Goolsby, M E
  • McCasland, W R
• Publication Date: 1969-8

Subject/Index Terms

• TRT Terms: Control devices; Equipment; Freeway operations; Freeways; Interchange ramps; Signals; Traffic control; Traffic crashes; Traffic speed; Traffic surveillance; Traffic volume; Travel time
• Uncontrolled Terms: Violations
• Old TRIS Terms: Freeway ramps; Freeway traffic accidents; Overall travel speed; Traffic control systems
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00225659
• Record Type: Publication
• Files: TRIS, USDOT
• Created Date: Apr 13 1970 12:00AM