(extract from our Traffic Calming Good Practice Guide)

Thumps are low narrow humps which have been installed at regular intervals as an alternative to other forms of humps. They are not recommended as it has been found that often drivers do not reduce speeds as they experience no increase in discomfort at faster speeds and increased bus maintenance costs have been reported.

Department for Transport Traffic Advisory Leaflet 7/96, found below, provides guidance on thumps and other types of road humps.