RESULTS OF SIGOP-TRANSYT COMPARISON STUDIES

THE SIGOP, A TRAFFIC SIGNAL OPTIMIZATION PROGRAM AND THE TRAFFIC NETWORK STUDY TOOL (TRANSYT), BOTH EMPLOY TWO BASIC ELEMENTS, NAMELY, A MODEL OF TRAFFIC FOR USE IN PREDICTING DELAY AND STOPS IN THE STREET NETWORK FOR ANY GIVEN TIMING PLAN; AND A SEARCH TYPE OF OPTIMIZATION PROCEDURE FOR IMPROVING A GIVEN TIMING PLAN. THE OBJECTIVE FUNCTION TO BE OPTIMIZED IS A WEIGHTED SUM OF DELAY AND STOPS WITH THE CHOICE OF WEIGHTS DECIDED BY THE TRAFFIC ENGINEER. DETAILS ARE GIVEN OF THE SIMILARITIES AND DIFFERENCES BETWEEN THE TWO SYSTEMS AND THE EVALUATORY EXPERIMENTS ARE DESCRIBED. TRAFFIC FLOWS WERE DETERMINED IN GLASGOW FROM PNEUMATIC DETECTORS WHILE SAMPLE MANUAL COUNTS PROVIDED TURNING MOVEMENT AND COMMERCIAL VEHICLE DATA. MINIMUM DELAY WAS THE CRITERION USED IN THE TRANSYT PROGRAM CALCULATION OF THE OPTIMUM LINK OFFSETS, I.E., NO COST WAS ASSOCIATED WITH STOPS. IN ORDER TO MINIMIZE THE NUMBER OF VARIABLES INVOLVED, THE SIGOP SETTINGS WERE CALCULATED USING THE SAME CYCLE TIMES AND GREEN SPLITS USED FOR TRANSYT. LATER MEASUREMENTS WERE MADE CONSISTING OF ONE WEEK OF TESTING SINGLE-CYCLE TRANSYT, TWO WEEKS OF SIGOP, AND TWO WEEKS OF DOUBLE-CYCLE TRANSYT. EVALUATORY STUDIES IN SAN JOSE WERE CONDUCTED BY MANUAL COUNTS, WITH DETECTOR DATA USED AS A TEST FOR RELIABILITY. THE FLOATING CAR TECHNIQUE USED IN GLASGOW IS OUTLINED. RESULTS OF THE EVALUATION STUDY ARE SUMMARIZED, TABULATED, AND DISCUSSED. THERE IS NO MEASURABLE DISTANCE BETWEEN SIGOP AND TRANSYT WHERE SHORT CYCLES ARE USED. HOWEVER, DOUBLE CYCLE TRANSYT WHEN TESTED, RESULTED IN TRAVEL TIME UP TO FIVE PERCENT LOWER THAN WITH SIGOP AND SINGLE-CYCLE TRANSYT. DOUBLE-CYCLE TRANSYT IS ONLY APPLICABLE WHERE MAJOR INTERSECTIONS REQUIRE CYCLE LENGHTS LONGER THAN ABOUT 80 SECONDS AND MINOR INTERSECTIONS ARE RELATIVELY LIGHTLY LOADED. THE TRANSYT PREDICTION MODEL APPEARS TO BE MORE OF A RELIABLE TOOL FOR TRAFFIC ENGINEER USE THAN THE SIGOP PREDICTION PROGRAM.

• Authors:
  • Kaplan, J A
  • POWERS, L D
• Publication Date: 1973-9

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 17-23
• Serial:
  • Traffic Engineering, Inst Traffic Engr
  • Volume: 43
  • Issue Number: 12

Subject/Index Terms

• TRT Terms: Alternatives analysis; Forecasting; Intersections; Signalization; Stopped time delays; Traffic delays; Traffic flow; Traffic measurement
• Uncontrolled Terms: Comparative analysis; Etching; Signal analysis
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00226823
• Record Type: Publication
• Files: TRIS
• Created Date: Apr 27 1974 12:00AM