THE ALBANY CBD NETWORK TRAFFIC SURVEILLANCE AND CONTROL SYSTEM
THIS PAPER REVIEWS THE NEARLY TWO YEARS OF ALMOST TROUBLE-FREE OPERATING EXPERIENCE OF THE ALBANY, NEW YORK, COMPUTERIZED TRAFFIC SIGNAL CONTROL SYSTEM. THE SYSTEM CONSISTS OF 20 SIGNALIZED INTERSECTIONS UNDER THE CONTROL OF A MINICOMPUTER MAKING SIGNAL TIMING DECISIONS BASED ON SURVEILLANCE INFORMATION FROM 65 INDUCTIVE LOOP DETECTORS. THE EXISTING CENTRAL CONTROL SYSTEM IS CAPABLE OF EXPANSION TO INCLUDE AS MANY AS 300 INTERSECTIONS. A LARGE VARIETY OF TWO TO FOUR-PHASE FIXED-TIME AND ACUATED CONTROLLERS ARE ACCOMMODATED. COMMUNICATIONS BETWEEN ALL INTERSECTIONS AND THE CENTRAL CONTROL IS ACCOMPLISHED OVER SEVERAL PAIR OF LINES USING FREQUENCY DIVISION MULTIPLEXING. TWO MINOR FAILURES IN THE COMPUTER, ABOUT A YEAR APART, RESULTED IN THE SIGNALS OPERATING UNDER LOCAL CONTROL FOR LESS THAN A TOTAL OF THIRTY-SIX HOURS. DUE TO LARGE FLUCTUATIONS IN THE PRIMARY POWER SUPPLY AT THE START OF THE FIRST SUMMER OF OPERATIONS, A HIGH RATE OF ON/OFF COMPUTER CYCLING WAS EXPERIENCED. THE QUICK AND SIMPLE REMEDY WAS A VOLTAGE REGULATING TRANSFORMER BETWEEN THE POWER LINE AND COMPUTER. MALFUNCTION OF THE COMMUNICATIONS EQUIPMENT CAN ORIGINATE IN THE LINE OR AT EITHER INTERFACE TERMINATION. TYPICAL INTERFACE MAINTENANCE HAS INCLUDED CLEANING CONTACTS OR REPLACING RELAY UNITS WHENEVER FAILURES OCCUR. RELIABLE SOLID STATE INTERFACES ARE NOW AVAILABLE THAT CAN OBVIATE THIS PROBLEM. COMMUNICATIONS LINE DIFFICULTIES INCLUDE NOISE BURSTS AND LINE BREAKS. THE FDM TECHNIQUE REDUCES TO ALMOST NEGLIGIBLE PROPORTIONS THE AFFECT OF SPURIOUS NOISE. LINE BREAKS HAVE BEEN LOCATED AND REPAIRED WITHIN A FEW HOURS. THUS, OVER THE LAST TWO YEARS, A CENTRAL CONTROL AVAILABILITY OF 99.5 PERCENT HAS PERMITTED THE CITY OF ALBANY TO REALIZE A SUBSTANTIAL IMPROVEMENT IN THE CAPACITY OF THE CBD STREET NETWORK, AND A SIGNIFICANT REDUCTION IN BOTH VEHICULAR DELAY AND ACCIDENT RATE. /AUTHOR/
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Corporate Authors:
Institute of Traffic Engineers
2029 K Street, NW
Washington, DC 20006 -
Authors:
- Yagoda, H N
- Wisepart, I S
- Principe, E H
- Publication Date: 1972-9
Media Info
- Features: Figures;
- Pagination: p. 151-6
- Serial:
Subject/Index Terms
- TRT Terms: Central business districts; Information processing; Loop detectors; Multiplexing; Pretimed traffic signal controllers; Traffic actuated controllers; Traffic control; Traffic signal control systems; Traffic surveillance
- Old TRIS Terms: Traffic control systems
- Subject Areas: Highways; Operations and Traffic Management;
Filing Info
- Accession Number: 00226561
- Record Type: Publication
- Files: TRIS
- Created Date: Apr 17 1973 12:00AM