THE DETERMINATION OF MERGING CAPACITY AND ITS APPLICATION TO FREEWAY DESIGN AND CONTROL - VOL IV

VOLUME 4 OF THE FINAL REPORT, PRESENTS A NEW APPROACH TO THE DETERMINATION OF THE CAPACITY AND SERVICE VOLUMES IN RAMP-FREEWAY MERGING AREAS. THE CAPACITY OF A MERGING AREA IS BASED ON THE CRITICAL GAP CONCEPT AND ON ASSUMPTIONS REGARDING THE DISTRIBUTION OF GAPS IN THE FREEWAY SHOULDER LANE. THE SERVICE VOLUMES SUGGESTED ARE DEVELOPED FROM CONSIDERATIONS OF THE RAMP JUNCTION AS A QUEUEING SYSTEM. A LEVEL OF SERVICE CAN THEN BE PROVIDED SUCH THAT A RAMP VEHICLE HAS A CERTAIN PROBABILITY OF FINDING THE MERGING AREA EMPTY. ANOTHER MEASURE OF LEVEL OF SERVICE IS THE DELAY SUFFERED BY RAMP VEHICLES. THIS ASPECT IS TREATED AND CHARTS PRESENTED FOR ITS DETERMINATION. THE ABOVE MERGING PARAMETERS ALL INVOLVE THE CRITICAL GAP OF THE JUNCTION. THIS CRITICAL GAP CAN BE ESTIMATED FROM THE GEOMETRICS OF THE RAMP-FREEWAY JUNCTION BY A REGRESSION EQUATION, DEVELOPED THROUGH THE STUDY OF A NUMBER OF ENTRANCE FACILITIES, WHICH RELATES THE CRITICAL GAP TO THE LENGTH OF ACCELERATION LANE AND THE ANGLE OF CONVERGENCE. RELATIONSHIPS ARE ALSO PRESENTED OF ESTIMATING THE ENTIRE GAP ACCEPTANCE CHARACTERISTICS FROM THESE TWO GEOMETRIC FEATURES. THE PAPER PROCEEDS TO DISCUSS IN DETAIL THE APPLICATION OF THE DEVELOPED MERGING PARAMETERS IN FREEWAY DESIGN AND CONTROL. /AUTHOR/

• Supplemental Notes:
  • Hpr, Cpr-11-2842
• Corporate Authors:

  Texas Transportation Institute

  Texas A&M University System, 1600 E Lamar Boulevard
  Arlington, TX  United States  76011
• Authors:
  • Drew, D R
  • Buhr, J H
  • Whitson, R H
• Publication Date: 1967

Subject/Index Terms

• TRT Terms: Acceleration lanes; Angularity; Freeways; Gap acceptance; Geometric design; Highway capacity; Highway design; Interchange ramps; Length; Level of service; Merging traffic; Queuing theory; Regression analysis; Traffic control; Traffic delays; Traffic volume
• Uncontrolled Terms: Angles; Convergence
• Old TRIS Terms: Freeway design; Freeway entrances and exits; Queueing theory
• Subject Areas: Data and Information Technology; Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00224856
• Record Type: Publication
• Source Agency: Bureau of Public Roads /US
• Files: TRIS
• Created Date: Jul 28 1994 12:00AM