Abstract
This paper reports the results of research into performance of Austrian motorways surfaced with porous asphalt. Hydraulic conductivity was found to reduce with time. Rolling noise reduction depended on particle size in the surface. Good values for skid resistance were found except immediately after laying. Climatic changes were found to be probably responsible for differences in the accident rate. Increased winter maintenance was needed, with regional glazed frost formation being a problem. Mechanical durability and environmental aspects were also studied.