Existence of traveling wave solutions in continuous optimal velocity models

Abstract

In traffic flow theory, hydrodynamic models, a subset of macroscopic models, can be derived from microscopic-level car-following models. Self-organized wave propagation, which characterizes congestion, has been replicated in these macroscopic models. However, the existence of wave propagation has only been validated using numerical technique or formal analyses and has not yet been rigorously proven. Therefore, analytical approaches are necessary to ensure their validity rigorously. This study investigates the properties of solutions corresponding to congestion with sparse and dense waves. Specifically, we demonstrate the existence of traveling back/front, traveling pulse, and periodic traveling wave solutions in macroscopic models. All theorems are proven using phase-plane analysis without local bifurcation theory. The key to the proofs is the monotonicity of solution trajectories concerning implicit parameters that naturally appear in the models. We also examine the global bifurcation structure for heteroclinic, homoclinic, and periodic orbits, which correspond to traveling back/front, traveling pulse, and periodic traveling wave solutions, via the numerical continuation package HomCont/AUTO.