REPORT ON COMMITTEE ON SIGHT DISTANCES, NEEDED RESEARCH FOR THE DETERMINATION OF SIGHT DISTANCES

TWO AND THREE-LANE HIGHWAYS SHOULD BE DESIGNED WITH TWO MINIMUM SIGHT DISTANCES IN MIND; ONE TO ACCOMMODATE THE PASSING OF MOTOR VEHICLE WITH SAFETY AND ONE FOR A NON-PASSING MINIMUM. IT IS DESIRABLE THAT THE SIGHT DISTANCE AT EVERY POINT ON A HIGHWAY SHOULD EXCEED THE PASSING MINIMUM. THIS GENERALLY IS NOT POSSIBLE, BUT IF DRIVERS ARE TO BE ENCOURAGED TO REMAIN BEHIND SLOWER MOVING VEHICLES UNTIL IT IS SAFE TO PASS, SAFE PASSING SECTIONS MUST BE ENCOUNTERED FREQUENTLY. SIGHT DISTANCE ADEQUATE FOR PASSING WITH SAFETY IS THE SUM OF THREE DISTANCES: THAT TRAVERSED DURING PERCEPTION TIME, THAT TRAVERSED WHILE PASSING, AND THAT TRAVERSED BY AN OPPOSING VEHICLE. RESEARCH IS REQUIRED TO DETERMINE PERCEPTION TIME, OR THE TIME ELAPSED FROM THE INSTANT THE ROAD OPENS UP TO THE VIEW OF THE DRIVER TO THE TIME HE BEGINS THE OPERATION OF PASSING, WHEN THE OPPOSING LANE IS FREE OF TRAFFIC; SPACING OF VEHICLES BEFORE AND AFTER PASSING; THE ACCELERATION OF THE VEHICLE; AND THE TIME OF PASSING. RESEARCH ALSO IS NEEDED TO DETERMINE MANY FACTORS WHICH INFLUENCE MOST DRIVERS IN ARRIVING AT A DECISION REGARDING THE PASSING OF SLOWER MOVING VEHICLES AND TO GAUGE THE ABILITY OF MOST DRIVERS TO PROPERLY UTILIZE LONG SIGHT DISTANCES. AT INTERSECTIONS RESEARCH IS REQUIRED FOR MANY FACTORS SIMILAR TO THOSE RELATED TO SIGHT DISTANCES ON THE ROAD, AND FOR OTHER FACTORS SUCH AS ACCELERATION OF VEHICLES FROM A STOPPED POSITION, WHICH ARE RELATED ONLY TO SIGHT DISTANCES AT INTERSECTIONS. ALL FACTORS MUST BE RELATED TO THE ASSUMED DESIGN SPEED OF THE HIGHWAY AND ALL RESEARCH SHOULD BE UNDERTAKEN WITH THIS END IN MIND. /AUTHOR/

• Record URL:
  https://onlinepubs.trb.org/Onlinepubs/hrbproceedings/17/17Pt1-006.pdf
• Supplemental Notes:
  • Vol 17, ParT I, PP 111-120; part of Report of Department of Design. 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:
  • Barnett, J
  • Greenshields, B D
  • Lauer, A R
• Publication Date: 1938

Media Info

• Media Type: Digital/other
• Monograph Title: Proceedings of the Seventeenth Annual Meeting of the Highway Research Board Held at Washington, D.C. November 30, December 1, 2, 3, 1937. Part I
• Serial:
  • Highway Research Board Proceedings
  • Volume: 17
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Acceleration (Mechanics); Design speed; Distance; Distance perception; Highway design; Highway safety; Intersections; Passing sight distance; Passing zones; Sight distance; Spacing; Stopping sight distance; Three lane highways; Two lane highways; Vehicles
• Old TRIS Terms: Determination; Perception distance; Sight distance /minimum non passing/; Sight distance, restricted passing
• Subject Areas: Design; Highways; Vehicles and Equipment;

Filing Info

• Accession Number: 00203487
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Aug 15 1971 12:00AM