This old TV episode (Hit and Run) of Highway Patrol shows a '52 Cadillac Ambulance on a run with lights and siren. It is at the 4:00 mark. Sorry, I don't know how to pull a clip or if it is even possible so the whole link is below. Lot of great old non-pro cars in this show as well even an early VW bug. Show was aired 2/15/1956. Enjoy
http://www.hulu.com/watch/104157/highway-patrol-hit-and-run#x-0,vepisode,1,0
http://www.hulu.com/watch/104157/highway-patrol-hit-and-run#x-0,vepisode,1,0