You may be relieved to hear Waymo is rolling out to Portland, Oregon. It's not in the south, and with over 150 rainy days per year, it ranks among the rainiest US cities.
Safer, cheaper, etc are less arbitrary.
The question is: why haven't you fixed this already?
Since you're of the opinion that this is taking too long, what do you think is a reasonable time for a fix, and why? I'm assuming Waymo didn't have a team of flood-detection experts twiddling their thumbs waiting to be prompted into action.