  We present a phase diagram of the different kinds of congested traffic that
are triggered by disturbances when passing ramps or other spatial
inhomogeneities of a freeway. The simulation results obtained by the nonlocal,
gas-kinetic-based traffic model are in good agreement with empirical findigs.
They allow to understand the observed trasitions between free and various kinds
of congested traffic, among them localized clusters, stop-and-go waves, and
different types of ``synchronized'' traffic. The proposed conditions for the
existence of these states suggest that the phase diagram is universal for a
class of different microscopic and macroscopic traffic models.
