What’s a rumble device designed to do?

Explanation: A rumble device consists of raised markings or strips, designed to give drivers an audible, visual and tactile warning. These devices are used in various locations, including in the line separating the hard shoulder and the left-hand lane on the motorway and on the approach to some hazards, to alert drivers to the need to slow down.

Category: Vehicle handling

References: Know Your Traffic Signs: Page 75