True, probably should be an and/or, but almost certainly you'll have a better time using both - RADAR's spatial resolution isn't nearly as good. Also probably because if they tried to put a LIDAR rig into a consumer car it'd push the price considerably. Unless they could magically get the price down (as Waymo claim) it would be a healthy fraction of the cost of the car. The Velodyne x64 unit cost about $75k not too long ago.
You can do weird tricks with RADAR though, like the two-car lookahead thing that Tesla has implemented. You can do that with LIDAR if you're looking at a mirror (you'll measure the distance to thing in the mirror), but typically multipath returns don't have a high enough SNR to be useful.
You can do weird tricks with RADAR though, like the two-car lookahead thing that Tesla has implemented. You can do that with LIDAR if you're looking at a mirror (you'll measure the distance to thing in the mirror), but typically multipath returns don't have a high enough SNR to be useful.