Final answer:
The triangular sign on a vehicle indicates it is a slow-moving vehicle, typically traveling at 25 mph or less, and other drivers should slow down and pass with caution.
Step-by-step explanation:
The sign with a triangle on a vehicle signifies that the vehicle is a slow-moving vehicle. This triangular sign usually has a bright orange or red border with a reflective red interior. It warns other drivers that the vehicle is traveling slower than the normal speed of traffic, typically 25 miles per hour or less. You will often see this sign on farm equipment, construction machinery, or other vehicles that are not capable of maintaining high speeds. It is important to slow down and pass with caution when you come across a vehicle with this sign.