As far as I'm aware, all L4 AV companies have done years of closed course testing. You can (not) see these vehicles being tested in places like GoMentum station in Concord, Altamont Raceway in Livermore, and TRC in Merced, not to mention other courses in Vegas, Seattle, Tahoe, AZ, Florida, Michigan, and China.
Of course, companies also started with small, slow vehicles like the Waymo firefly and the Nuro R vehicles. Voyage (acquired by Cruise) was doing their testing in a low speed access controlled retirement community, with essentially golf carts.
Of course, companies also started with small, slow vehicles like the Waymo firefly and the Nuro R vehicles. Voyage (acquired by Cruise) was doing their testing in a low speed access controlled retirement community, with essentially golf carts.