SOME REMARKS ON MACROSCOPIC TRAFFIC FLOW MODELING

This note contributes to the discussion on the current state and the p rospectives of macroscopic traffic flow modelling. It is argued that m acroscopic traffic flow models may never reach the descriptive accurac y level of other domains in physics and engineering. On the other hand , there is an eminent need for computer codes emulating dynamic traffi c phenomena for various traffic engineering tasks (simulation, plannin g, control strategy design and testing etc.) hence the need to emphasi ze practical model validation work at the current stage of development s. Some properties of macroscopic traffic flow models are outlined and the usefulness of second-order approaches, as evidenced in empirical validation results, is underlined. (C) 1998 Elsevier Science Ltd. All rights reserved.