Abstract
The number of speed reducing road humps in villages and cities has shown significant increase since the last CROW recommendations in 1988. Certainly the `Duurzaam Veilig' initiative of the Dutch Ministry of Transport, Public Works and Water Management has contributed to this growth. After all the final goal of this project is to set up 50% of the residential areas as 30 kph zones. No statistics are available on the current number of road humps in an average municipality, but it is estimated there must be thousands of them aiding traffic calming in the larger cities. These humps do not always comply with the CROW recommendations in force.