Where: On any road.
Purpose: To warn that the level of the right-hand side of the carriageway is higher than the left-hand side, or the left-hand side of the carriageway is higher than the right-hand side.
Action: Slow down and be aware that your vehicle may tend to the left or right if you straddle the step between the higher and lower level. Because of the ridge vehicles may also be slow to return to the higher level and could react suddenly if the wheel mounts the ridge. Do not make any sudden jerking steering