Why would anyone think that was a good idea
That's what it looks like to me too. They always used big Caddys and Lincolns for that. I think they call them gate cars and the are used in harness racing.This looks like a vehicle modified to use at a horse race track. The gates would extend out and the horses would line up and follow the car at low speed. Then the gates would fold back and the horses were off.
Kind of like a horse race pace car.
Found it. I saw it as a kid.