A police siren is a loud, attention-grabbing sound used by law enforcement vehicles, such as police cars, to alert the public of their presence. The siren helps clear the way for emergency responders, allowing them to reach their destinations quickly and safely. Typically, police sirens produce a variety of tones and patterns, which can vary by region or department. These sounds are designed to be heard over traffic noise and other environmental sounds, ensuring that drivers and pedestrians are aware of the approaching emergency vehicle.