Abstract
In the fourth part of the state of the art report "traffic flow models" the behaviour of macroscopic traffic flow characteristics in dynamic situations is discussed. The models are mostly formulated here as one, or as a system of, partial differential equations. First the so called input-output models are discussed. Secondly the modes which describe the propagation of a certain traffic flow situation and which describe a modification in such a flow in position and in time, are discussed. For abstracts of parts 1, 2 and 3, see IRRD abstracts nos 240606 to 240608.