URBAN TRAFFIC CONTROL: HOW FAR CAN WE TAKE IT?

BECAUSE OF THE DIFFICULTIES OF CONSTRUCTING URBAN HIGHWAYS ON NEW RIGHTS-OF-WAY, CONSIDERABLE ATTENTION HAS BEEN FOCUSED ON THE USE OF URBAN TRAFFIC CONTROL SYSTEMS (UTCS) TO EXPEDITE FLOW AND INCREASE CAPACITY. AS THE STOCHASTIC NATURE OF TRAFFIC FLOW MAKES PREDICTION OF SYSTEM STATE QUITE DIFFICULT, REAL-TIME CONTROL SYSTEMS ARE INCREASINGLY ATTRACTIVE. CURRENT RESEARCH AND DEVELOPMENT PROJECTS IN REAL-TIME CONTROL REVIEWED TO ASSESS THE STATE-OF-THE- ART AND POTENTIAL IMPROVEMENTS WITH RESPECT TO PRESENTATION AND PROCESSING OF INFORMATION FOR HARDWARE AND DRIVER AND TO TYPE OF CONTROL, DEGREE OF CONTROL, AND TIMING. IT IS NOTED THAT AT HIGH VOLUMES A TRAFFIC-RESPONSIVE SYSTEM IS PUSHED TO THE UPPER LIMITS WHERE THE CYCLE IS DETERMINED BY THE MAXIMUM ALLOWABLE PHASE TIMES, AT WHICH POINT IT BEHAVES LIKE ANY OTHER FIXED-TIME CONTROLLER WITH THE SAME CYCLE LENGTH AND SPLIT, BREAKING DOWN IN THE SAME WAY AS VOLUMES INCREASE AND DELAYS BECOME INFINITE. ACCORDINGLY, UTCS SHOULD BE REGARDED NOT SOLELY FROM THE STANDPOINT OF INTERSECTION CAPACITY AND ARTERIAL FLOW BUT ALSO FROM THAT OF INFORMATION AND CONTROL FUNCTIONS RELATING TO SPEED CONTROL, REROUTING THROUGH THE STREET NETWORK, STORAGE OF DOWNSTREAM O & D INFORMATION FOR SUBSEQUENT REAL-TIME CONTROL, AND PRETRIP CONTROL OF TRAVEL ITSELF. EACH OF THESE FOUR APPLICATIONS WOULD HAVE ITS OWN EFFECTS ON BUS OPERATIONS. FREEWAY OPERATIONS WOULD BENEFIT MOST FROM THE THIRD TYPE OF CONTROL--COMBINING O & D INFORMATION WITH MANDATORY ROUTING.

• Authors:
  • Brand, D
• Publication Date: 1972-8

Media Info

• Features: Figures; Photos;
• Pagination: p. 50-5
• Serial:
  • Traffic Engineering, Inst Traffic Engr
  • Volume: 42
  • Issue Number: 8

Subject/Index Terms

• TRT Terms: Demand; Drivers; Highway capacity; Information management; Information processing; Information, data, and knowledge; Intersections; Motor vehicles; Origin and destination; Real time control; Routing; Traffic assignment; Traffic control; Travel
• Uncontrolled Terms: Intersection capacity
• Old TRIS Terms: Real-time systems
• Subject Areas: Data and Information Technology; Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00226458
• Record Type: Publication
• Files: TRIS
• Created Date: Dec 13 1972 12:00AM