Fire Truck Lights and Sirens
Emergency and first responder vehicles depend on emergency lights to serve several important purposes. Essentially they are there to convey the urgency of the situation to oncoming traffic so that they may let the responding vehicle pass. But that's not always their purpose. Sometimes a blue warning light could mean that there is a problem on the road ahead like an accident. In other instances, the lights may be used by law enforcement as a sign to the driver of a vehicle to pull over.