GREAT!
Now all I need know is who built it and why and I will be able to die happy!
The only reason I can think of for such a light would be for use as a "Follow Me" car at an airport. Either that, or as a clever device to lure unsuspecting motorists in the Alps to drive over a cliff and kill themselves.
Oh, wait! How about a pace car kinda thingie?
As you can tell, being privy to the knowledge that this thing has a big damn light on the roof advances my understanding of it origins or history not at all.....