Privacy issues aside, the data volume would be far to high for the cars mobile connection to transfer. But if they only send whenever the actual and the expecta

Privacy issues aside, the data volume would be far to high for the cars mobile connection to transfer. But if they only send whenever the actual and the expectation differs, e.g. the cars GPS track deviates locally from the map data, or whenever the driver disagrees with the autopilot, they can get a lot of information. With this new usage of the radar, they seem to create "radar maps" of all radar echoes from bridges and traffic signs. Using those maps they should be able to detect true obstacles with a high enough confidence to enable automatic braking/evasion. The problem so far with automatic braking by radar is not so much with detecting possible obstacles but with false positives. A car must not randomly brake when there is no obstacle.