Where:
On any road, but especially in mountainous or hilly areas where the road slopes sharply downward.
These signs are often placed before long or dangerous downhill stretches to alert drivers to adjust their driving accordingly.

Purpose:
To warn that the road ahead descends steeply, which can affect a vehicles speed and braking performance.
On steep declines, vehicles particularly heavy ones like trucks or buses, may gain speed quickly and require more distance to stop.
The sign ensures drivers are prepared to control their speed and drive safely down the hill.

Action:
Reduce speed before starting the descent.
Select a lower gear to use engine braking instead of relying only on the brakes, as continuous braking can cause brake failure due to overheating.
Be alert for slow-moving or heavy vehicles, such as trucks, that may be descending at reduced speeds.
Maintain a safe following distance and be ready for sharp bends or curves often found on steep roads.
Use caution in wet or slippery conditions, as braking distances will increase.