Use in water protection areas

Contaminated surface water may not run off roads and motorways which pass through water protection areas. 

The RiStWag (German Guidelines for Construction Measures on Roads in Water Extraction Areas ("Richtlinie für bautechnische Maßnahmen an Straßen in Wassergewinnungsgebieten")) require rainwater to be carried out of the protection zone in watertight channels and pipes within water protection zones II and III A. Reinforced concrete slot units with and without kerb reliably fulfil this requirement.