  We focus in this work on the study of traffic in open systems using a
modified version of an existing cellular automaton model. We demonstrate that
the open system is rather different from the closed system in its 'choice' of a
unique steady-state density and velocity distribution, independently of the
initial conditions, reminiscent of self-organised criticality. Quantities of
interest such as average densities and velocities of cars, exhibit phase
transitions between free flow and the jammed state, as a function of the
braking probability R in a way that is very different from closed systems.
Velocity correlation functions show that the concept of a dynamical cluster,
introduced earlier in the context of granular flow is also relevant for traffic
flow models.
