AN EVALUATION OF TRAFFIC SIGNAL COORDINATION. FINAL REPORT

THE IMPACT OF A FLEXIBLE COORDINATED TRAFFIC SIGNAL SYSTEM ON THE TRAFFIC PATTERNS AND FLOW OF A MEDIUM SIZE CITY WAS STUDIED TO (1) EVALUATE THE ADVANTAGES OF A FLEXIBLE COORDINATED SYSTEM OVER LESS SOPHISTICATED AND LESS COSTLY SYSTEMS, AND (2) TO DETERMINE WHETHER THE BENEFITS DERIVED JUSTIFIED THE COST OF THE FLEXIBLE SYSTEM. THE PROJECT WAS STARTED IN THE FALL OF 1962 AT WHICH TIME THE CITY OF LAFAYETTE, INDIANA, IN COOPERATION WITH THE INDIANA STATE HIGHWAY COMMISSION, HAD CONTRACTED TO HAVE A FLEXIBLE COORDINATED TRAFFIC CONTROL SYSTEM INSTALLED IN THE CENTRAL BUSINESS DISTRICT OF THE CITY. THIS SYSTEM UTILIZED ELECTRO-MATIC PR COORDINATED SIGNAL CONTROL SYSTEM EQUIPMENT MANUFACTURED BY THE AUTOMATIC SIGNAL DIVISION OF LABORATORY FOR ELECTRONICS, INC. THIS INSTALLATION AFFORDED A GREAT OPPORTUNITY TO OBTAIN THE DATA REQUIRED TO EVALUATE THE IMPACT AND ECONOMIC CONSEQUENCES OF A SYSTEM OF THIS TYPE ON A MEDIUM SIZED CITY. TRAVEL TIME RUNS, WITH SIMULTANEOUS VOLUMES TAKEN, WERE CONDUCTED FOR THREE DIFFERENT MODES OF SIGNAL OPERATION: UNCOORDINATED RANDOM, A COORDINATED SIMULTANEOUS, AND COORDINATED SINGLE ALTERNATE. IN ORDER TO ISOLATE THE EFFECT OF THE SIGNAL TIMING ON DELAYS, RUNS INVOLVING OTHER DELAYS DUE TO PEDESTRIANS, TURNING CARS, AND PARKING CARS WERE DISCARDED. THIS ALLOWED THE RELATIONSHIPS AMONG VOLUME, TRAVEL TIME, AND SIGNAL MODE TO BE DETERMINED. THE ANALYSIS WAS INTENDED TO REVEAL WHICH SYSTEM FUNCTIONED MOST EFFICIENTLY AT DIFFERENT VOLUME LEVELS; HOWEVER, THE FLEXIBLE SYSTEM WAS SHOWN TO BE SUPERIOR TO THE OTHER MODES OVER THE ENTIRE RANGE OF VOLUMES TESTED. THE FLEXIBLE SYSTEM PRODUCED SIGNIFICANT SAVINGS IN TOTAL TRAVEL TIMES, DELAY TIMES, AND NUMBER OF STOPS PER RUN FOR ALL VOLUMES. AN ECONOMIC EQUATION WAS DEVELOPED, AND THE FLEXIBLE SYSTEM WAS SHOWN TO REALIZE A SAVINGS IN DELAY TIME AND OPERATING COSTS VALUED AT THE PRESENT TIME OF APPROXIMATELY $140,000 PER YEAR. AT A 10% RATE OF RETURN, THIS ANALYSIS ALSO SHOWED THE FLEXIBLE SYSTEM TO HAVE CUT DELAY TIME AND OPERATING COSTS BY AN AMOUNT EQUAL TO THE INITIAL CAPITAL COST OF THE SYSTEM IN LESS THAN TWO YEARS FROM THE COMPLETION OF ITS INSTALLATION. /AUTHOR/

• Supplemental Notes:
  • No 17, 87 PP, 18 FIG, 15 TAB, 23 REF, 2 APP
• Corporate Authors:

  Purdue University/Indiana Department of Transportation JHRP

  Purdue University, School of Civil Engineering
  West Lafayette, IN  United States  47907-1284
• Authors:
  • Cooper, C E
• Publication Date: 1971-9

Subject/Index Terms

• TRT Terms: Alternatives analysis; Costs; Evaluation; Operating costs; Traffic delays; Traffic signal control systems; Travel time
• Subject Areas: Finance; Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00226105
• Record Type: Publication
• Files: TRIS
• Created Date: Jan 17 1972 12:00AM