EVALUATION OF ON-FREEWAY TRAFFIC CONTROL AT AN INTERCHANGE

DUE TO IMBALANCE OF TRAFFIC DEMAND DURING PEAK HOURS AND TO A LANE REDUCTION AT MERGE AREAS, TRAFFIC CONGESTION IS OCCURRING AT MAJOR INTERCHANGES DURING PEAK PERIOD OPERATION. THE PREMISE IS THAT BETTER INTERCHANGE OPERATION IS ACHIEVED BY TRAFFIC CONTROL OR MINOR GEOMETRIC MODIFICATION. IN HOUSTON, THE MERGE AREAS AT TWO INTERCHANGES WERE CONSIDERED AS POSSIBLE STUDY SITES FOR EVALUATION OF PART OF THE PREVIOUS PREMISE. PRELIMINARY ANALYSIS INDICATED THAT ONE OF THE INTERCHANGES WOULD BE A DESIRABLE SITE FOR A PILOT STUDY. A MORNING AND AN EVENING STUDY AT THE INTERSTATE 610 AND INTERSTATE 10 WEST INTERCHANGE WERE MADE TO EVALUATE THE EFFECTS OF ON-FREEWAY CONTROL AS A MEANS OF IMPROVING THE MERGE OPERATION. USING STANDARD MAINTENANCE PROCEDURES, THE OUTSIDE FREEWAY LANE UPSTREAM OF THE MERGE AREA WAS CLOSED FOR A SHORT PERIOD OF TIME AT THE BEGINNING OF THE MERGE CONGESTION. BASED ON VEHICLE COUNTS AND AVERAGE VEHICLE STUDIES WHICH WERE COLLECTED BEFORE AND DURING THE CLOSURE STUDY, A COMPARISON OF CHANGES IN FLOW RATES AND IN TOTAL DELAY WAS MADE. SINCE ACCIDENT DATA WERE NOT AVAILABLE, ONLY NON-INCIDENT DAYS WERE ANALYZED. DURING THE MORNING AND EVENING CLOSURES, THE FLOW RATES THROUGH THE MERGE AREAS DID NOT CHANGE; HOWEVER, THE MORNING CLOSURE CAUSED A NINE PERCENT INCREASE IN DELAY, WHEREAS THE EVENING CLOSURE REDUCED DELAY BY TWO PERCENT. THE AVERAGE FLOW RATE ON THE TWO OPEN FREEWAY LANES DURING THE CLOSURE WAS ABOUT 1650 VEHICLES PER HOUR PER LANE. IT WAS FOUND THAT IMPLEMENTATION OF POSITIVE LANE CLOSURE WAS TOO TIME CONSUMING FOR A SHORT CLOSURE. THEREFORE, IT WAS CONCLUDED THAT THE METHOD OF POSITIVE CLOSURE WAS NOT THE OPTIMAL SOLUTION FOR THIS INTERCHANGE. FURTHER STUDIES USING OTHER METHOD OF ON-FREEWAY CONTROL HAVE BEEN RECOMMENDED. /AUTHOR/

• Supplemental Notes:
  • RESEARCH REPORT 139-10
• Corporate Authors:

  Texas Transportation Institute

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

  Texas State Department of Highways & Public Transp

  11th and Brazos Streets
  Austin, TX  United States  78701
• Authors:
  • Loutzenheiser, R C
  • Henderson, D M
• Publication Date: 1971-8

Media Info

• Features: Figures; References; Tables;
• Pagination: 43 p.

Subject/Index Terms

• TRT Terms: Freeway operations; Freeways; Highway operations; Interchanges; Lane closure; Merging traffic; Peak hour traffic; Traffic; Traffic congestion; Traffic control; Traffic flow; Traffic lanes
• Uncontrolled Terms: Closures
• Old TRIS Terms: Lanes
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00226346
• Record Type: Publication
• Files: TRIS, STATEDOT
• Created Date: Aug 3 1972 12:00AM