OPTIMAL SYNCHRONIZATION OF TRAFFIC SIGNAL NETWORKS BY DYNAMIC PROGRAMMING

THIS PAPER PRESENTS A SYNCHRONIZATION METHOD FOR DETERMINATION OF OPTIMAL OFFSETS IN ROAD TRAFFIC NETWORKS CONTROLLED BY FIXED-TIME SIGNALS. THE METHOD IS BASED ON DYNAMIC PROGRAMMING AND PROVIDES AN OPTIMAL SOLUTION, INDEPENDENT OF NETWORK LAYOUT, IN A FINITE NUMBER OF COMPUTATION STEPS. THE MATHEMATICAL MODEL OF THE SYNCHRONIZATION PROBLEM IS INTRODUCED FIRST. DEFINITIONS OF THE SYSTEM'S INDEPENDENT VARIABLES ARE GIVEN AND THE EQUATIONS CHARACTERIZING THE CONSTRAINTS IMPOSED ON THE OFFSET ACROSS-VARIABLES ARE FORMULATED. THE DEPENDENT VARIABLES OF THE SYSTEM ARE THE COST FUNCTIONS ASSOCIATED WITH EACH LINK OF THE TRAFFIC NETWORK. THE OPTIMIZATION TARGET IS A MINIMIZED ECONOMIC OBJECTIVE FUNCTION COMPRISING THE INDIVIDUAL LINK FUNCTIONS AND POSSIBLY IN- CLUDING DELAY TIMES AS WELL AS STOPS. THE PROBLEM IS NONLIN- EAR (OWING TO THE CHARACTER OF THE LINK COST FUNCTIONS) AND CONTAINS INTEGER VARIABLES IN THE CIRCUIT CONSTRAINT EQUA- TIONS. THE ALGORITHM FOR ITS SOLUTION IS BASED ON PARTIAL MINIMIZATIONS CONCLUDED BY DETERMINING A FUNDAMENTAL SET OF OPTIMAL OFFSETS AS WELL AS THE OPTIMAL VALUE OF THE OBJECT- IVE FUNCTION. IN ORDER TO OVERCOME THE "CURSE OF DIMENSION- ALITY" INHERENT IN MULTIVARIABLE PROBLEMS, A DECISION-TREE ALGORITHM IS EMPLOYED FOR OBTAINING A MINIMIZATION PLAN WHICH IS OPTIMAL IN TERMS OF THE COMPUTATIONAL EFFORT INVESTED. THE AIM, IN THIS CASE, IS TO MINIMIZE THE REQUIRED COMPUTER STORAGE CAPACITY AND NUMBER OF OPERATIONS.

• Authors:
  • Gartner, N
• Publication Date: 1972

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 281-95
• Serial:
  • Traffic Flow and Transportation

Subject/Index Terms

• TRT Terms: Algorithms; Costs; Mathematical models; Pretimed traffic signal controllers; Traffic delays; Traffic signal control systems
• Uncontrolled Terms: Synchronization
• Subject Areas: Finance; Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00226792
• Record Type: Publication
• Files: TRIS
• Created Date: Dec 22 1973 12:00AM