You'd be surprised how well the lidar systems on these actually do see in the rain. Snow and ice is another story, and hydroplaning as well, but again it's not the sensors hampering it here. It's the logic. It's much more complicated than it first appeared, and right now the AI for detection and recognition is light years beyond where the self driving car logic is. You can watch a few YouTube videos of people training networks to drive cars (and also look at how well every company is currently doing) to see how difficult it is to get an AI solution for driving behavior.
They work well when they are working. Things a different when something blocks the lens, when a mirror bounces the laser back on itself, or when the laser's view is obstructed by something (ussually the road) that isnt up to code. Then the concept of lidar as reliable or even useful comes into question. Forget the math of driving, it is beyond today's lidar to tell whether there is frost on its own lens, a very basic safety proceedure.
