Final answer:
A triangular orange-color sign on the back of a slow-moving vehicle indicates that the vehicle is traveling at a significantly reduced speed. It is used to alert other drivers to exercise caution when approaching or overtaking the vehicle.
Step-by-step explanation:
When you see a triangular orange-color sign on the back of a slow-moving vehicle, it means that the vehicle is traveling at a significantly reduced speed. This is often seen on vehicles such as farm machinery, construction equipment, or vehicles used for maintenance work on the road. The purpose of these signs is to alert other drivers that the vehicle ahead is moving slowly and to exercise caution when approaching or overtaking it.