TRAFFIC PERFORMANCE AT URBAN STREET INTERSECTIONS

A PRELIMINARY EXPLORATION WAS CONDUCTED INTO THE FUNDAMENTAL RELATIONSHIPS WHICH EXIST BETWEEN TRAFFIC UNITS. METHODS AND THE MORE COMMONLY OBSERVED TRAFFIC PHENOMENA OF ACCELERATION AND DECELERATION WERE OBSERVED. THE SEVERAL COMPONENTS OF THE PERFORMANCE OF VEHICLE STARTING AT URBAN INTERSECTIONS WERE INVESTIGATED. REACTION TIMES TO THE LIGHT CHANGE AND BETWEEN VEHICLES WERE FOUND TO BE IN SOME MEASURE DEPENDENT ON PEDESTRIAN MOVEMENT. SEVERAL METHODS OF PRESENTING STARTING-TIME-DISTANCE PERFORMANCE WERE USED FOR THE SAKE OF CLARITY. THE TIME-DISTANCE RELATIONSHIPS AT START PROVED TO BE SIMILAR AT THE DIFFERENT INTERSECTIONS STUDIED. TWO METHODS FOR DETERMINING THEORETICAL INTERSECTION CAPACITY WERE PRESENTED AND THEIR PRACTICAL APPLICATION DISCUSSED. IT IS CONCLUDED THAT A VERY SMALL PERCENTAGE OF DECELERATIONS IN ACTUAL PRACTICE REACH THE POSSIBLE MAXIMUM. THERE ARE TWO TYPES OF DECELERATION, THE FUNCTIONAL, AND WHAT HAS BEEN CALLED CHRONOTROPIC. NO TIME IS LOST DUE TO NOT TAKING ADVANTAGE OF MAXIMUM DECELERATION IN THE LATTER TYPE. THE TRAFFIC DELAY IN URBAN AREAS IS NOT CLOSELY RELATED TO THE RATES OF DECELERATION EMPLOYED SINCE MOST STOPS ARE OF A CHRONOTROPIC NATURE. A TECHNIQUE OF TIME-SPACING ANALYSIS IS APPLIED TO TRAFFIC BEHAVIOR AT NON- CONTROLLED INTERSECTIONS. PHYSICAL CHARACTERISTICS OF THE INTERSECTION AFFECT THE BEHAVIOR OF THE DRIVERS INSOFAR AS THEIR ABILITY TO MAKE EARLY DECISIONS AND AVOID DELAY IN CROSSING IS CONCERNED. THERE IS A TENDENCY AT THE NON- CONTROLLED INTERSECTIONS FOR THE MAJOR STREAM OF TRAFFIC TO BE AGGRESSIVE AND TO FORCE THE MINOR TO GIVE WAY. IN GENERAL, TIME-SPACE RELATIONSHIPS GOVERN THE BEHAVIOR OF MOTORISTS AT UNSIGNALIZED INTERSECTIONS. ROAD TRAFFIC CONFORMS SO WELL TO POISSON'S RANDOM SERIES THAT ITS APPLICATION LEADS TO RESULTS OF PRACTICAL IMPORTANCE. IT IS POSSIBLE TO DETERMINE DELAY AT SIGNALIZED INTERSECTIONS THROUGH THE USE OF POISSON'S FORMULA. A THEORETICALLY CORRECT METHOD HAS BEEN DEVELOPED. THE THEORY, IN REGARD TO SIGNALS WHICH FAIL TO CLEAR SOME VEHICLES RETARDED DURING THE RED PERIOD, IS DEVELOPED SINCE POISSON'S FORMULA IS APPLICABLE TO THIS PROBLEM AS WELL. THE TRAFFIC PROBLEM TREATMENT BY PROBABILITY THEORY AND OTHER PRINCIPALS DEVELOPED IN THIS STUDY ARE ONLY EXEMPLARY OF A VARIETY OF APPLICATIONS.

  • Corporate Authors:

    Bureau Highway Traffic, Yale University

    ,    

    Eno Foundation for Highway Traffic Control

    1250 I Street, NW
    Washington, DC  USA  20005
  • Authors:
    • Greenshields, B D
    • Schapiro, D
    • Ericksen, E L
  • Publication Date: 1946

Media Info

  • Pagination: 152 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00227722
  • Record Type: Publication
  • Report/Paper Numbers: Tech Rpt 1
  • Files: TRIS
  • Created Date: Aug 15 2004 1:26AM