What does a yellow and black sign with a truck going downhill indicate?

A yellow and black sign depicting a truck going downhill indicates that a steep grade is ahead. This warning is essential for drivers, particularly those operating larger vehicles like trucks, which may have difficulty maintaining control on steep descents due to their weight. The sign serves as an alert to check the vehicle's brakes and to prepare for a change in speed and handling requirements, ensuring that the driver can navigate the terrain safely.

In the context of driving regulations, this sign is crucial for both the safety of the driver and other road users, as it helps prevent accidents caused by losing control on steep slopes. Awareness of such warnings helps all drivers appropriately adjust their speed and driving techniques when approaching steep grades.