  We study a system of interacting self-propelled particles whose walking
velocity depends on the stage of the locomotion cycle. The model introduces a
phase equation in the optimal velocity model for vehicular traffic. We find
that the system exhibits novel types of flow: synchronized free flow,
phase-anchoring free flow, orderly jam flow, and disordered jam flow. The first
two flows are characterized by synchronization of the phase, while the others
do not have the global synchronization. Among these, the disordered jam flow is
very complex, although the underlying model is simple. This phenomenon implies
that the crowd behavior of moving particles can be destabilized by coupling
their velocity to the phase of their motion. We also focus on "phase-anchoring"
phenomena. They strongly affect particle flow in the system, especially when
the density of particles is high.
