Well the driver did provide input, he touched the gas pedal, which disengaged the autonomous system and put the vehicle in manual mode, and that's presumably what you want to have happen.
When it's time to disengage the vehicle you don't want to be fighting for control with the computer, manual override needs to be on a hair trigger in case the computer makes a sudden error. Unfortunately so long as there's a human in the loop, the propensity for human error is going to be there. I honestly don't know what Waymo could do to prevent this, multiple bells and whistles went off.
Waymo takes this stuff very seriously, they absolutely do not want to have to face the music should one of their vehicles get into an at-fault accident or suffer some other kind of catastrophic failure.
I just did a Google News search for "asleep at the wheel", and in the last week a few people have been killed, a few more hospitalized, and the more minor incidents don't even get reported. Waymo sincerely wants to solve this, but there's an awkward no-mans land between no autonomy and fully autonomous where Vigilance Decrement[1] is an issue.
Fortunately this was a minor accident. Waymo's test fleet reportedly covers 25,000 miles a day, and in regular day to day driving minor accidents happen about once every 160,000 miles. So if incidents like this are happening once a week for Waymo, that's about par for the course.
https://en.wikipedia.org/wiki/Vigilance_(psychology)#Vigilan...