A VOLUME WARRANT FOR URBAN STOP SIGNS

NUMERICAL STANDARDS ARE DEVELOPED FOR SOME OF THE CONDITIONS UNDER WHICH STOP SIGNS SHOULD BE USED. THE PURPOSES SERVED BY STOP SIGNS FALL INTO TWO CATEGORIES: (1) REDUCTION OF ACCIDENT HAZARDS, AND (2) FACILITATION OF TRAFFIC MOVEMENT. RESEARCH WAS CONDUCTED TO FORMULATE ADEQUATE STOP SIGN WARRANTS. THE STUDY WAS DIVERTED TO DEVELOPING A STOP-SIGN WARRANT FOR RIGHT-ANGLED CROSSINGS THAT ARE: (1) IN URBAN AREAS, AND (2) ISOLATED IN THE SENSE OF NOT BEING PART OF A THROUGH-STREET SYSTEM. IN ORDER TO DETERMINE THE FACTORS ON WHICH A VOLUME WARRANT MUST DEPEND, IT WAS NECESSARY TO FIND THE FIELD METHOD THAT WOULD PERMIT MEASUREMENTS OF THE FOLLOWING TRAFFIC CHARACTERISTICS: (1) MAIN-STREET VOLUME, (2) SIDE-STREET VOLUME, (3) TIMES OF ALL ARRIVALS AND DEPARTURES OF CARS ON BOTH STREETS, AND (4) NUMBER OF DELAYED CARS ON THE SIDE STREET. A GRAPHIC TIME-RECORDER WAS USED AND WAS OPERATED FROM INSIDE A PARKED CAR. A VOLUME-WARRANT WAS DEVELOPED FOR INSTALLING 2-WAY STOP SIGNS AT URBAN INTERSECTIONS. THE WARRANT WAS BASED ON THE PERCENTAGE OF SIDE-STREET CARS THAT MEET INTERFERENCE FROM TRAFFIC ON THE MAIN STREET. IN APPLYING THE WARRANT TO A SPECIFIC INTERSECTION, THREE QUANTITIES NEED TO BE MEASURED: (1) THE MAIN-STREET VOLUME, (2) THE SIDE-STREET VOLUME, AND (3) A QUANTITY CALLED THE CRITICAL LAG, WHICH IS A CONSTANT FOR EACH PARTICULAR INTERSECTION BUT VARIES FROM ONE INTERSECTION TO ANOTHER. THE RECOMMENDED WARRANT IS BASED ON THE PRINCIPLE THAT A STOP SIGN IS NEEDED IF THE PERCENTAGE OF SIDE-STREET TRAFFIC WHICH CAN BE EXPECTED TO BE DELAYED EXCEEDS 50 PERCENT. THE DELAYED PERCENTAGE COMPUTATION IS PRESENTED. THE APPLICATION OF MATHEMATICAL THEORY OF PROBABILITY TO THE MOVEMENTS OF TRAFFIC WAS EXTENDED. A START WAS MADE TOWARD A THEORETICAL EXPLANATION OF INTERACTION BETWEEN TWO INTERSECTING STREAMS OF TRAFFIC, WHEN BOTH STREAMS ARE DISTRIBUTED AT RANDOM. STUDY CONCLUSIONS INDICATE THAT: (1) THE CRITICAL LAG VARIES FROM ONE INTERSECTION TO ANOTHER, BUT THERE IS NEED FOR ADDITIONAL RESEARCH TO DISCOVER WHAT OTHER INTERSECTION CHARACTERISTICS ARE MOST CLOSELY RELATED TO THE CRITICAL LAG, (2) THE AVERAGE LENGTH OF DELAYS FOR SIDE-STREET CARS DOES NOT CORRELATE WELL WITH TRAFFIC VOLUMES, AND IS THEREFORE NOT A GOOD BASIS FOR A SIGN WARRANT, AND (3) THE USEFULNESS OF THE MATHEMATICAL THEORY WAS EXTENDED, BUT THERE REMAINS THE PROBLEM OF TAKING ADEQUATE ACCOUNT OF THE SLUGGISH STARTING OF A LINE OF STOPPED CARS.

• Record URL:
  https://rosap.ntl.bts.gov/view/dot/16265
• Supplemental Notes:
  • 121 Pp, 36 FIG, 13 TAB, 2 APP
• Corporate Authors:

  Eno Foundation for Highway Traffic Control

  1250 I Street, NW
  Washington, DC  United States  20005
• Authors:
  • Raff, M S
• Publication Date: 1950

Subject/Index Terms

• TRT Terms: Gap acceptance; Highway operations; Intersections; Measurement; Prevention; Probability theory; Queuing; Safety; Stop signs; Traffic; Traffic delays; Traffic volume; Urban areas; Warrants (Traffic control devices)
• Subject Areas: Data and Information Technology; Highways; Operations and Traffic Management; Safety and Human Factors; Security and Emergencies;

Filing Info

• Accession Number: 00227753
• Record Type: Publication
• Files: NTL, TRIS
• Created Date: Aug 15 2004 2:04AM