Final answer:
Overhanging objects behind a vehicle must have a red flag when they extend more than 1 meter beyond the vehicle.
Step-by-step explanation:
According to traffic regulations, overhanging objects behind a vehicle must have a red flag when they extend more than 1 meter beyond the vehicle. This is to ensure that other drivers can easily see and avoid any potential hazards caused by these objects. It is important to follow these rules to maintain safety on the road.