What’s a rumble device designed to do?

Rumble Devices

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.

SABRE, the Society for All British and Irish Road Enthusiasts, also have information on them.