[azernik]

> but mixed with radar can it be effective enough.

The usual solution is actually lidar + optical; lidar gives much better spatial resolution than radar, which is why it's been the standard going back to the DARPA challenge. You really want to have good spatial resolution in order to distinguish e.g. bikers and tail-lights and road signs for your optical systems, which radar typically isn't good enough for; that's the point of that qualifier in "imaging radar". Still probably worse performance (i.e. time and spatial resolution) than lidar, but better range and weather resistance.

(The previous generation of Waymo cars already had one lidar on top; the radar and the close-range lidars are the new additions.)