DIAGRAMMATIC SIGNS

Engage lower gear
Where: On the left-hand side of the road.
Purpose: To warn that, because of a steep descent, it is necessary to engage a lower gear.
Action: If you are driving a heavy motor vehicle, engage a lower gear so that the vehicle will move down the descent more slowly.

Overhead lane use control by regulation
Where: In any lane of any road.
Purpose: To inform you by means of a diagram that the lane below the sign is subject to a compulsory requirement indicated by a 'command' or 'prohibition' regulatory sign.
Action: Do not turn in at such a road unless you are going to a destination in the road that ends.