'We' have already succeeded in autonomous driving in agricultural and mining domains - these are much simpler, more tightly controlled and less liability prone than open highways and suburban backstreets.
eg:
> We run more than 130 autonomous trucks, part of our Autonomous Haulage System, across our Iron Ore operations. The trucks are operated by a supervisory system and a central controller, rather than a driver. The system uses pre-defined GPS courses to automatically navigate haul roads and intersections and knows actual locations, speeds and directions of all vehicles at all times.
> In 2018, each truck was estimated to have operated on average 700 hours more than conventional haul trucks, with 15% lower costs – delivering clear productivity benefits. They also take truck operators out of harm’s way, reducing the risks associated with working around heavy machinery.