Many years ago I worked as an EMT for Beacon Ambulance Service in Raleigh, NC. One evening, my driver (John) and I were responding to an emergency call in our old reliable chariot, "Beacon 5."
Looking in a rear view mirror, there were a total of 15 flashing red lights, plus the two headlights wig-wagging. On the roof was a Federal Q2 mechanical siren operated by a foot switch. The torque on that monster would literally twist the front end on spin up.
Adding to the audio mayhem was an electronic Federal siren, for which I have forgotten the precise model number.
Any way, eventually our way was blocked by a very slow moving Cadillac battle tank being driven by a little old lady. She was completely oblivious to both the sirens and the lights. We could see the "wash of red light" that was illuminating her car's interior.
After a few frustrating minutes, I reached over and blew the unit's anemic horn.
That she heard! In any event, it startled her so much that she jerked the wheel, ran off the road directly into a tree. We had to stop to aid her and call for a backup unit to take over our original call.
Beacon #5 was in the center: