Apparently, this is how a company called Saint-Gobain PAM Canalisation tests the manhole covers and different kinds of street grates it builds for strength and durability. Not only is the motion of the carrousel satisfying but just listen to the singing of the tire over the metal and concrete, especially at lower speeds:

I’ve got to stop paying for those meditation apps like a sucker and just play this thing on a loop. I probably would if the video had just slightly better sound quality, as there are a few cracks in there. Maybe Saint-Gobain PAM should go into ASMR videos instead of ductile iron pipes.