A TRAFFIC SIGNAL SYSTEM FOR HIGH-SPEED ROADS

ON THE APPROACH TO TRAFFIC SIGNALS, THE "DILEMMA ZONE" IS WHERE MOST DRIVERS, AT THE ONSET OF THE AMBER SIGNAL, FIND THEMSELVES IN THE PREDICAMENT OF BEING TOO CLOSE TO THE INTERSECTION STOP LINE TO STOP SAFELY OR COMFORTABLY, AND YET TOO FAR FROM IT TO CLEAR THE INTERSECTION BEFORE THE RED SIGNAL IS DISPLACED. THE DEVELOPMENT OF A TRAFFIC SIGNAL SYSTEM IS DESCRIBED FOR USE ON HIGH SPEED ROADS. THE AIM OF THE SYSTEM IS TO REDUCE THE RISK OF DRIVER ERROR BY MINIMIZING THE CHANCE OF THE TRAFFIC SIGNALS CHANGING FROM GREEN TO AMBER WHILE A VEHICLE IS WITHIN THE DILEMMA ZONE ASSOCIATED WITH ITS APPROACH SPEED. THE EQUIPMENT DEVELOPED CONSISTS OF A SERIES OF CONVENTIONAL VEHICLE LOOP-DETECTORS INSTALLED IN THE ROADWAY ON THE HIGH SPEED APPROACH TO THE SIGNALS. THSE DETECTORS ARE COUPLED TO A STANDARD TRAFFIC SIGNAL CONTROLLER THROUGH A TIMING AND DETECTOR OUTPUT CONTROL DEVICE WHICH RENDERS THE DETECTORS SENSITIVE TO VEHICLES IN CERTAIN SPEED RANGES. THE RELATIONSHIP BETWEEN THE DISTANCE OF EACH DETECTOR FROM THE STOP LINE AND THE RANGE OF ITS SPEED SENSITIVITY ARE DERIVED FROM CRAWFORD'S EXPERIMENTAL RESULTS ON DRIVER JUDGMENT AND ERROR DURING THE AMBER PERIOD AT TRAFFIC LIGHTS. /HSRI/

• Supplemental Notes:
  • Rpt No 3/71, 29 PP, FIGS, PHOTS, REFS
• Corporate Authors:

  Motor Transport Dept /Australia

  /Traffic Accident Research Unit
  ,   United States 
• Authors:
  • Messiter, G F
• Publication Date: 1971-6

Subject/Index Terms

• TRT Terms: Detectors; High speed ground transportation; High speed vehicles; Loops (Control systems); Roads; Signal generators; Signals; Speed; Traffic actuated controllers; Traffic control; Traffic signals; Yellow interval (Traffic signal cycle)
• Old TRIS Terms: Detecting devices; Loop
• Subject Areas: Highways; Operations and Traffic Management; Railroads;

Filing Info

• Accession Number: 00226271
• Record Type: Publication
• Source Agency: Highway Safety Research Institute
• Files: TRIS
• Created Date: May 16 1972 12:00AM