  We study the formation of localized shocks in one-dimensional driven
diffusive systems with spacially homogeneous creation and annihilation of
particles (Langmuir kinetics).We show how to obtain hydrodynamic equations
which describe the density profile in systems with uncorrelated steady state as
well as in those exhibiting correlations. As a special example of the latter
case the Katz-Lebowitz-Spohn model is considered. The existence of a localized
double density shock is demonstrated for the first time in one-dimensional
driven diffusive systems. This corresponds to phase separation into regimes of
three distinct densities, separated by localized domain walls. Our analytical
approach is supported by Monte-Carlo simulations.
