1 Estimating PM-emission reductions from speed management

Speed reduction measures have become an increasingly popular way to increase traffic safety especially in urban areas. Recently many cities have converted entire districts into 30 km/h zones. In many European countries the maximum speed of haulage trucks is under discussion or review sometimes in combination with a ban on overtaking. Reducing the maximum speed is perceived and promoted by policy makers as beneficial to the environment because of reduced fuel consumption and lower emissions. These claims however have not been scientifically validated. They stem from the popular believe that the widely used Copert-approach, which is scientifically valid for average trip speeds, can be used to assess the environmental impact of speed management policies at a local scale. It is obvious that speed reductions in urban areas or on highways may have very different effects on PM emissions. On the other hand the simplistic idea that speed reductions increase urban emissions and decrease emissions on highways is probably wrong. Although fe