When did emergency service vehicles swap bells etc. for electric sirens?
sort by best latest
You can help the HubPages community highlight top quality content by ranking this answer up or down.
Thank you very much, Mehul1427, but I've already looked there. I need a year, which is not given. I'm thinking of fire, ambulance and police and the two-tone horn. Would it have been used during the late 40s and 50s?