What is a Rumble Device on the road designed to do?

Ivy School of Motoring - This mornings theory question was What's a rumble device designed to do? The answer is 'D'. Were you right? The explanation A rumble device consists of raised

Rumble Strip

Improving Road Safety and Traffic Safety

Portable Temporary Rumble Strips (PTRS)

Rumble strip - Wikipedia

The Invention of the Rumble Strip

Rumble strips boost work-zone safety in Wisconsin

All you need to know about Rumble Strips Device

Speed reduction methods to promote road safety and to save lives – Making Cities Safer