I've seen this rig before; it's how the GM factories test that a car's doors, hood, trunk lid and windows are all properly installed and adjusted to ensure a waterproof seal. But, I s'pose it could also be used as a car wash.
Some one just asked me this question. My reply is that my 4 day a week 2004 Ford Focus, now 20 years old, and been hand washed by me at over 900 times. The older two day a week 91 Mazda, 13 year ownership has been washed about 338 times by hand. All vintage cars are under covers so are washed 3X per year now. I clean every nook and cranny, door jambs, trunk and hood jambs. and toothbrush around trim. Yes, I am that anal on all my work.
I won’t go to a roller brush car wash, for fear of rusty bits of other cars stuck in the brush. I also won’t go to a touchless high pressure wash, since last time it blasted some decal and pinstripe off my vintage wagon. So what I do is go to a cheap manual wash during non peak hours. Put in the minimum coinage, soap it up and spray out the underside, until the time is up. Then go over the whole thing with a microfiber cloth, removing any dirt, oil, bugs, tar marks, old tire shine, etc. Then with minimum coinage I rinse it off using the wax, bottom and top, until the time is up. Then afterwards I take it somewhere nearby, dry off what’s left of the water, and take a magic eraser to the windows. It really shines. This is what I do before every show, and several times throughout the summer.