THE CAPACITY OF SIGNALIZED INTERSECTIONS IN AUSTRALIA

NEW APPROXIMATIONS HAVE BEEN DERIVED FOR THE PROBABILITY OF CLEARING THE QUEUE AND FOR THE AVERAGE NUMBER OF VEHICLES LEFT IN THE QUEUE AT THE END OF THE PHASE AT FIXED-TIME SIGNALS. SATURATION FLOWS HAVE BEEN MEASURED IN SEVEN AUSTRALIAN CITIES. THESE ARE EXPRESSED IN THROUGH CAR UNITS (TCU'S). THIS METHOD SAVES THE NEED TO ESTIMATE THE DISTRIBUTION OF COMMERCIAL VEHICLES AND TURNING VEHICLES BETWEEN LANES. THE FOLLOWING EQUIVALENTS, IN TERMS OF THROUGH CARS BEING 1 UNIT HAVE BEEN FOUND: A LEFT TURNING CAR IS EQUIVALENT TO 1 1/2 UNITS; A LEFT TURNING COMMERICAL VEHICLE, 2 1/2; AND A THROUGH COMMERCIAL VEHICLE, 2. A FORMULA IS PRESENTED FOR THE EQUIVALENTS FOR OPPOSED RIGHT-TURNING CARS AND COMMERCIAL VEHICLES. AVERAGE EQUIVALENTS ARE 2.9 AND 3.9 FOR RIGHT-TURNING CARS AND COMMERCIAL VEHICLES RESPECTIVELY. SATURATION FLOWS HAVE BEEN FOUND TO BE ALMOST CONSTANT FOR LANE WIDTHS BETWEEN 10 FT AND 13 FT. A TABLE IS GIVEN OF AVERAGE SATURATION FLOWS AS A FUNCTION OF THE TYPE OF LANE AND THE LOCALITY WITHIN THE CITY. AT APPROACHES WITH THREE OR MORE LANES, IT HAS BEEN FOUND THAT ABOUT 40 PER CENT OF THE AVAILABLE KERB LANE CAPACITY IS UTILIZED WHEN PARKING IS BANNED. THIS INCREASES TO 60 PER CENT WHEN STOPPING IS BANNED AND THIS IS ENFORCED BY POLICE. IT IS RECOMMENDED THAT THE AVERAGE LOST TIME PER CHANGE OF PHASE SHOULD BE TAKEN AS EITHER THE INTERGREEN TIME MINUS 1/2 SEC, OR 2 1/2 SEC PLUS THE TRAVEL TIME THROUGH THE INTERSECTION OF THE LAST VEHICLE, WHICHEVER IS LONGER. /RRL/A/

• Record URL:
  • http://arrbknowledge.com
• Supplemental Notes:
  • No 3, 95 Pp, 11 FIG, 17 TAB, 26 REF
• Authors:
  • Miller, A J
• Publication Date: 0

Media Info

• Serial:
  • Australian Road Research Board Bulletin

Subject/Index Terms

• TRT Terms: Automobiles; Commercial vehicles; Highway capacity; Intersections; Percent saturation; Queuing; Traffic counting; Traffic flow; Traffic lanes; Traffic signal cycle; Traffic signal timing; Width
• Uncontrolled Terms: Intersection capacity
• Old TRIS Terms: Types
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00227760
• Record Type: Publication
• Source Agency: Road Research Laboratory /UK
• Files: TRIS
• Created Date: Apr 9 1971 12:00AM