A Hybrid Optimal Velocity Drag Model for Traffic Flow Dynamics

We develop a Hybrid Optimal Velocity-Drag (OVD) model that combines the behavioral structure of the classical Optimal Velocity Model (OVM) with a drag-based saturation law motivated by Newtonian mechanics. The model retains the OVM principle that desired speed depends on headway, but replaces the linear relaxation law with a formulation that enforces bounded accelerations and smooth convergence to equilibrium. After reviewing the OVM framework and its stability properties, we introduce the OVD dynamics and derive the dispersion relation from a linear stability analysis of uniform flow. This analysis shows that the OVD formulation preserves the instability mechanisms responsible for stop-and-go waves, while avoiding the unrealistic acceleration predictions of the classical OVM. We also illustrate the model using desired velocity functions of hyperbolic tangent type, a common choice in the OVM literature, and highlight applications to large-scale traffic simulation and empirical data studies. Taken together, our results demonstrate that the OVD model enforces bounded accelerations while preserving the nonlinear instabilities of the classical OVM, providing a physically grounded and interpretable foundation for advancing traffic flow research.