  As a typical self-driven many-particle system far from equilibrium, traffic
flow exhibits diverse fascinating non-equilibrium phenomena, most of which are
closely related to traffic flow stability and specifically the
growth/dissipation pattern of disturbances. However, the traffic theories have
been controversial due to a lack of precise traffic data. We have studied
traffic flow from a new perspective by carrying out large-scale car-following
experiment on an open road section, which overcomes the intrinsic deficiency of
empirical observations. The experiment has shown clearly the nature of
car-following, which runs against the traditional traffic flow theory.
Simulations show that by removing the fundamental notion in the traditional
car-following models and allowing the traffic state to span a two-dimensional
region in velocity-spacing plane, the growth pattern of disturbances has
changed qualitatively and becomes qualitatively or even quantitatively in
consistent with that observed in the experiment.
