  We introduce and study a deterministic lattice model describing the motion of
an infinite system of oppositely charged particles under the action of a
constant electric field. As an application this model represents a traffic flow
of cars moving in opposite directions along a narrow road. Our main results
concern the Fundamental diagram of the system describing the dependence of
average particle velocities on their densities and the Phase diagram describing
the partition of the space of particle configurations into regions having
different qualitative properties, which we identify with free, jammed and
hysteresis phases.
