# MULTIPATH TRAFFIC MODEL WITH DYNAMIC INPUT FLOWS

TRANSPORTATION PROBLEMS ARE AMONG THE MOST SIGNIFICANT BEING FACED BY SOCIETY TODAY. MUCH EFFORT IS BEING EXPENDED ON THE PLANNIFICATION FOR SYSTEMS WHICH ARE EFFICIENT, ACCEPTABLE TO MAN AND COMPATIBLE WITH HIS ENVIRONMENT. TO SOLVE THESE PROBLEMS WE NEED THE DEVELOPMENT OF POWERFUL TOOLS THAT ENABLE THE TRANSPORTATION PLANNERS TO COMPREHEND THE PHENOMENA OF TRANSPORTATION AND TO FIND SOLUTIONS WELL PROPORTIONAL TO THE AMOUNT FOR THE STATIONARY CASE. /AUTHOR/ ASSUMPTION MADE BY ALMOST EVERY TRAFFIC MODEL IN USE TODAY IN TRANSPORTATION PLANNING, THAT IS THE ASSUMPTION OF THE STATIONARITY OF THE TRAFFIC FLOW WHERE THE INPUT FLOWS ARE ASSUMED CONSTANT THROUGH TIME. IT IS IMPORTANT TO REFINE THE PRESENTLY USED TRAFFIC MODELS WHICH ARE SUPPOSED TO SIMULATE THE REALITY TO THE CASE OF NON-STATIONARY MODELS. THE STUDY OF THE DYNAMIC ASPECT OF THE TRAFFIC FLOW PATTERNS, THEIR EVOLUTION WITH TIME AND LOCATION IS A KEY TO A BETTER UNDERSTANDING OF THE TRANSPORTATION PHENOMENA. WE PRESENT IN THIS STUDY AN APPROACH TO THE REALIZATION OF THIS GOAL BY ADAPTING THE PROBABILISTIC MULTIPATH ASSIGNMENT MODEL TO THE CASE OF NON-STATIONARY INPUT FLOWS. THE PROBABILISTIC MULTIPATH ASSIGNMENT MODEL INTRODUCED BY DIAL (TRANS. RES. : 5, PP. 83-111; 1972) IS A MULTIPATH GENERALIZATION OF THE ALL-OR-NOTHING MODEL AND SUBSUMES IT AS A PARTICULAR CASE. GIVEN NON-STATIONARY INPUT FLOWS THE ASSIGNMENT MODEL EVALUATES FOR EACH POINT OF THE TRANSPORTATION NETWORK, THE FLOW DISTRIBUTION THROUGH TIME. THIS ALLOWS TO STUDY THE FORMATION AND THE EVOLUTION OF CONGESTIONS AND GIVES A MUCH PRECISE IMAGE OF THE REALITY. THE ALGORITHM IMPLEMENTING THIS DYNAMIC MODEL USES REPEATEDLY AN ADAPTED VERSION OF THE ALGORITHM FOR THE STATIONARY CASE AND A FAST FOURIER TRANSFORM PROCEDURE. THE AMOUNT OF WORK REQUIRED IS A FUNCTION OF THE PRECISION NEEDED. FOR A GIVEN PRECISION IT IS

• Supplemental Notes:
• Rept No 121
• Corporate Authors:

University of Montreal

Center for Research on Transportation (CRT)/CIRRELT
P.O. Box 6128, Station Centre-ville
Montreal, Quebec  Canada  H3C 3J7
• Authors:
• Robillard, P
• Publication Date: 1973-3

## Media Info

• Features: Figures; References;
• Pagination: 21 p.

## Filing Info

• Accession Number: 00227408
• Record Type: Publication
• Files: TRIS
• Created Date: Jul 16 1974 12:00AM