  We use a cellular automata approach to numerically investigate traffic flow
patterns on a single lane. The free-flow phase (F), the synchronized phase (S),
and the jam phase (J) are observed and the transitions among them are studied
as the vehicular density $\rho$ is slowly varied. If $\rho$ is decreased from
well inside the J phase, the flux $\Phi$ follows the lower branch of the
hysteresis loop, implying that the adiabatic decrease of $\rho$ is not an
efficient way to put the system back into S or F phases. We propose a simple
way to help the system to escape out of J phase, which is based on the local
information of the velocities of downstream vehicles.
