That doesn't mean it can't be solved. Don't drive faster than you can see. If you're driving 6 feet from a parked car, you can go slow enough to stop assuming a worst case of a sprinter waiting to leap out at every moment.
If that's too annoying then bad parking by school areas so the situation doesn't happen.
And why would you make Waymo's go slower than human drivers, when it's the human drivers with worse reaction times? I had interpreted the suggestion as applying to all drivers.