I'm honestly curious what test tracks Tesla uses. Do they just rent private tracks for their road testing before it gets to public beta? It clearly isn't done onroad by safety drivers.

GM has Milford and Yuma + others, Waymo has Castle, Zoox uses Altamont Raceway, Nuro has a track at the Vegas speedway. I can't imagine Tesla's small Fremont loop and their winter track in Fairbanks are sufficient.