Road environment descriptors - a database for integrating urban environment protection aspects in route guidance systems

Road environment descriptors (REDs) are one result of a research project for large-scale traffic assessment tasks used by the Federal Transport Masterplan of the German Ministry of Transport, Building and Housing. The main component is a cost-benefit analysis step, which results in a ranking list where all projects are ordered by their specific cost-benefit quotient. The assessment of traffic impact on urban areas and on the people living in those regions has a very high political importance in the actual masterplan. In the research project, we have analysed the usual methods of traffic impact assessment and filtered out the most-used indicators to estimate traffic noise, pollutant elements, separation effects and "linger quality". Essential indicators are urban land use, distance between developments across the carriageway, density of development (open or closed coverage), height of buildings and the people exposed. The Federal Transport Masterplan covers the whole of Germany, but the indicators we have to provide deal with small-scale aspects of urban land use and transport planning. As expected, we discovered that there is no complete and uniform database in Germany to retrieve these indicators