Which color light is used when climbing uphill to indicate the vehicle is moving under load?

• A. Red
• B. Amber
• C. White
• D. Green

Answer: (B)

Amber lights communicate caution and non-standard operation. When a vehicle is climbing uphill with a load, its speed may slow and the engine work increases, so using an amber warning light signals to others that the vehicle isn’t moving at normal speed and extra space may be needed. This helps prevent surprises for following drivers and keeps traffic safer. Red is for stop or danger, white is for visibility or reversing, and green generally means proceed or clear, so amber fits best for indicating the vehicle is moving under load.