What signals indicate that a motorist should yield the right of way?

In the context of right-of-way rules, the correct answer is the combination of both lights and siren. This combination is crucial for indicating that emergency vehicles, such as police cars, ambulances, or fire trucks, are responding to a call and need to navigate through traffic safely and quickly. The use of flashing lights alerts other motorists to the presence of an emergency vehicle, while the siren serves as an audible warning, further emphasizing the need for drivers to yield.

This dual signaling method is established to enhance road safety and facilitate faster responses in critical situations, ensuring that emergency personnel can reach their destinations without unnecessary delays. Drivers are trained to recognize the importance of adhering to these signals, as they play a life-saving role during emergencies.

In contrast, flashing headlights alone may not carry the same immediate urgency or authority as combined lights and siren. Similarly, warning lights on their own do not convey the full context of an emergency situation as effectively as including a siren. Lastly, a stop sign is a clear right-of-way indicator but applies to regular traffic scenarios, rather than the urgent circumstances that emergency vehicles encounter. Therefore, the combination of both lights and siren is essential for conveying the need to yield in emergency situations.