Final answer:
A 3-sided red Yield sign instructs drivers to slow down and yield right-of-way, stopping if necessary for safety, to let other road users proceed first.
Step-by-step explanation:
A 3-sided red Yield sign means that drivers must slow down and be prepared to stop if necessary to let any vehicles, bicyclists, or pedestrians pass before they proceed. It is a regulatory sign used to assign the right-of-way, indicating that drivers must yield to others but do not necessarily have to come to a complete stop unless it's needed for safety. This sign is typically found at intersections where it is deemed unnecessary to have a full stop, or in situations where a stop might actually impede traffic flow. Yield signs help to keep traffic moving smoothly, provided that drivers adhere to the rules and give the right-of-way when required.