EVALUATION OF FREEWAY TRAFFIC FLOW AT RAMPS, COLLECTOR ROADS, AND LANE DROPS

THIS STUDY WAS DESIGNED TO EVALUATE FREEWAY TRAFFIC FLOW CHARACTERISTICS FOR SEVERAL HIGH-STANDARD GEOMETRIC DESIGN FEATURES. THE STUDY EVALUATES AND COMPARES THE EFFECT OF DIFFERENT RAMP TYPES, SPACING, AND VOLUMES ON FREEWAY CAPACITY AND OPERATION. COLLECTOR-DISTRIBUTOR ROADS, AUXILIARY LANES, AND LANE DROPS ARE INCLUDED. THE PRIMARY MEASURE OF EFFECTIVENESS USED FOR THIS STUDY WAS DENSITY (VEHICLES PER LANE-MILE). DENSITY WAS CHOSEN RATHER THAN SPEED BECAUSE IT IS A BETTER INDICATION OF DRIVING CONDITIONS. THE MAJOR FINDING OF THIS STUDY IS THAT FREEWAY DESIGNS THAT OFFER GREATER FLEXIBILITY (FREEDOM OF CHOICE TO THE DRIVERS) WILL RESULT IN SMOOTHER AND MORE EFFICIENT OPERATION. FOR EXAMPLE, A FREEWAY WITH AUXILIARY LANES HAS GREATER FLEXIBILITY THAN A FREEWAY WITH A COLLECTOR ROAD SYSTEM WITH THE SAME TOTAL NUMBER OF LANES. IT ALSO HAS GREATER CAPACITY AND MORE EFFICIENT OPERATION.

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/hrr/1973/432/432-003.pdf
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309021626
• Supplemental Notes:
  • Sponsored by Commitee 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:
  • Martin, Darryl B
  • Newman, Leonard
  • Johnson, Roger T
• Conference:
  • 52nd Annual Meeting of the Highway Research Board
  • Location: Washington District of Columbia, United States
  • Date: 1973-1-22 to 1973-1-26
• Publication Date: 1973

Media Info

• Media Type: Digital/other
• Features: Appendices; Figures; Tables;
• Pagination: pp 25-30
• Monograph Title: Relations between geometric design and operations
• Serial:
  • Highway Research Record
  • Issue Number: 432
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Auxiliary lanes; Freeway operations; Freeways; Highway capacity; Interchange ramps; Lane drops; Location; Spacing; Streets; Traffic density; Traffic flow
• Old TRIS Terms: Collector distributor roads; Freeway capacity; Freeway ramps; Ramp location & spacing
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00226767
• Record Type: Publication
• ISBN: 0309021626
• Files: TRIS, TRB
• Created Date: Dec 22 1973 12:00AM