REDUCING IMBALANCE OF INTERSECTING FREEWAYS BY ON-FREEWAY CONTROL

BECAUSE OF A HEAVY TRAFFIC DEMAND ON MERGING RAMPS DURING PEAK PERIODS AND A LANE IMBALANCE AT THE MERGE AREAS, AN INTERCHANGE OF INTERSTATE 610 AND INTERSTATE 10 IN HOUSTON HAS RAMP QUEUES THAT FREQUENTLY EXTEND ONTO UPSTREAM FREEWAYS. A MORNING AND AN EVENING STUDY WAS MADE TO EVALUATE THE EFFECT OF ON-FREEWAY CONTROL AS A MEANS OF IMPROVING THE MERGE OPERATION. STANDARD MAINTENANCE PROCEDURES WERE USED TO CLOSE THE OUTSIDE FREEWAY LANE UPSTREAM OF THE MERGE AREA FOR A SHORT PERIOD OF TIME AT THE BEGINNING OF THE MERGE CONGESTION. BASED ON VEHICLE COUNTS AND AVERAGE VEHICLE DATA THAT WERE COLLECTED BEFORE AND DURING THE CLOSURE STUDY, A COMPARISON OF CHANGES IN FLOW RATES AND IN TOTAL DELAY WAS MADE. BECAUSE ACCIDENT DATA WERE NOT AVAILABLE, ONLY NONINCIDENT DAYS WERE ANALYZED. DURING MORNING AND EVENING CLOSURES, THE FLOW RATES THROUGH THE MERGE AREAS DID NOT CHANGE; HOWEVER, THE MORNING CLOSURE CAUSED A 9 PERCENT INCREASE IN DELAY, WHEREAS THE EVENING CLOSURE REDUCED DELAY BY 2 PERCENT. THE AVERAGE FLOW RATE ON THE 2 OPEN FREEWAY LANES DURING CLOSURE WAS ABOUT 1,650 VEHICLES PER HOUR PER LANE. IMPLEMENTATION OF POSITIVE LANE CLOSURE WAS TOO TIME-CONSUMING FOR A SHORT-TERM CLOSURE. THEREFORE, THE METHOD OF POSITIVE CLOSURE USED IN THIS STUDY WAS NOT THE OPTIMAL SOLUTION FOR THIS INTERCHANGE. /AUTHOR/

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/hrr/1972/388/388-003.pdf
• Supplemental Notes:
  • Sponsored by Committee on Operational Effects of Geometrics. 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:
  • Loutzenheiser, Roy C
  • Henderson, Donald M
• Publication Date: 1972

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: pp 22-31
• Monograph Title: Freeway operations and control
• Serial:
  • Highway Research Record
  • Issue Number: 388
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Merging traffic; Queuing; Ramps; Traffic flow; Traffic lanes; Vehicles
• Subject Areas: Highways; Operations and Traffic Management; Vehicles and Equipment;

Filing Info

• Accession Number: 00226397
• Record Type: Publication
• Report/Paper Numbers: No 390 PP 36-9
• Files: TRIS, TRB
• Created Date: Sep 19 1972 12:00AM