Do you recognize the sound of the hi-lo safety siren? The hi-lo is a distinctive two-tone siren used by patrol cars and other public safety vehicles in the event of an emergency like a fire or flood when an immediate evacuation is required. When you hear the hi-ho siren, it means you must evacuate immediately. Watch this brief video with Nader Oweis, Chief of Police with the Sonoma State University Police Department, to become familiar with the hi-lo siren sound and remember, when you hear the h