A Game Theoretical Approach for Modelling Merging and Yielding Behavior at Freeway On- Ramp Section 1 CHAPTER 9 A GAME THEORETICAL APPROACH FOR MODELING MERGING AND YIELDING BEHAVIOR AT FREEWAY ON-RAMP SECTION

Traffic conflicts between merging and through vehicles are typical phenomena near freeway on-ramp sections, yet few microscopic models describing the interaction of these vehicles in the merging process have been proposed. In this paper, vehicle interactions during merging process are modeled under an enhanced game-theoretic framework. Freeway on-coming through vehicle and on-ramp merging vehicle are considered as competing players that seek to maximize their respective rewards during the merging process. As the freeway vehicle aims to maintain their initial car-following state and minimize speed variations, the on-ramp merging vehicle strives to join mainline traffic in the minimal time possible subject to safety constraints. Considering non-cooperative nature of the game, drivers at the merging section would eventually adopt strategies that form Nash equilibrium. To assess the model parameters, we propose a bi-level estimation methodology with the upper level as a least square problem and the lower level a linear complementarity problem searching for the equilibria. Applicability of the proposed model is examined and validated using trajectory data collected from field. Testing results indicate that this framework can effectively capture vehicle interactions at freeway merging sections while achieving a relatively high accuracy of predicting vehicles’ actions. 1 Corresponding author: Civil Engineering Department, University of Minnesota, 500 Pillsbury Drive S.E., Minneapolis, Minnesota 55455, U.S.A. Email: [email protected] 2 A Game Theoretical Approach for Modelling Merging and Yielding Behavior at Freeway On-Ramp Section