What’s a rumble device designed to do?
The then Department of Transport produced a leaflet which outlines the concept of Rumble Devices very well. Although it was produced in 1993 the concept is still the same today. It states:
Features with a vibratory and audible effect can be used, usually in rural areas, to alert drivers to take greater care in advance of a hazard such as a bend or junction. In combination with a gateway they can indicate the entry to a village or the start of a series of traffic calming measures. They have also been used to designate the start of shared use roads in new residential developments.