PEAK-PERIOD ANALYSIS AND CONTROL OF A FREEWAY SYSTEM

SEVERAL METHODS OF OPERATING A SYSTEM OF FREEWAY RAMP CONTROLS DURING MORNING AND AFTERNOON RUSH OR PEAK PERIODS ARE CURRENTLY UNDER CONSIDERATION BY TRAFFIC ENGINEERS. SOME IDEAS ON AN OPTIMIZATION APPROACH TO THIS CONTROL PROBLEM ARE PRESENTED HERE. THE VARIABLE TO BE OPTIMIZED /IN THIS CASE MAXIMIZED/ IS THE TOTAL OUTPUT RATE OF THE CRITICAL PORTION OF THE FREEWAY SYSTEM. SINCE THIS HAS BEEN SHOWN TO BE ESSENTIALLY EQUIVALENT TO MINIMIZING THE TOTAL TRAVEL TIME OCCURRING TO ALL VEHICLES USING THE FREEWAY DURING THE PEAK PERIOD. IN THE CONTROL SYSTEM PROPOSED, EACH FREEWAY ENTRANCE RAMP /IN THE DIRECTION OF THE PEAK FLOW/ IS METERED AT A RATE WHICH MAINTAINS THE TOTAL MERGING FLOW RATE AT OR BELOW A RATE SET BY A CONTROL COMPUTER. THE CENTRAL COMPUTER DETERMINES THE OPTIMUM MERGING FLOW RATES BY SOLVING AN APPROPRIATE LINEAR PROGRAMMING PROBLEM. THE CONTINUITY CHARACTERISTICS OF CLOSED TRAFFIC SYSTEMS ARE USED TO DETECT REDUCED CAPACITY OCCURRENCES /ACCIDENTS, ETC./ AND TO DETERMINE THE CAPACITY FLOW RATE AT SUCH LOCATIONS. THIS INFORMATION IS USED AS INPUT FOR A MODIFIED L-P MODEL WHICH IS SOLVED TO DETERMINE OPTIMUM OPERATION UNDER EXISTING CONDITIONS. /BPR/

• Corporate Authors:

  Texas Transportation Institute

  Texas A&M University System, 1600 E Lamar Boulevard
  Arlington, TX  United States  76011
• Authors:
  • Wattleworth, J A
• Publication Date: 1965-10

Subject/Index Terms

• TRT Terms: Centralized traffic control; Computers; Control systems; Detection and identification; Detectors; Freeways; Highway capacity; Interchange ramps; Linear programming; Mathematical models; Merging traffic; Methodology; Operations; Output; Peak hour traffic; Proposals; Rates; Reduction (Chemistry); Traffic control; Traffic flow; Variables
• Uncontrolled Terms: Models
• Old TRIS Terms: Centralized control; Critical areas; Freeway entrances and exits; Freeway ramps; Metering; Reduction; Traffic control systems
• Subject Areas: Administration and Management; Highways; Operations and Traffic Management; Research;

Filing Info

• Accession Number: 00224812
• Record Type: Publication
• Report/Paper Numbers: Hpr 1/4/
• Files: TRIS
• Created Date: Jan 1 1994 12:00AM