I have questions about Waymo's taxi service. I'm certain that they occasionally run into situations that require human intervention, or at least need to be prepared for such an eventuality (see examples below). In such scenarios, what happens? The passenger operates the car? A remote operator takes controls? The car refuses to move and becomes a hazard or causes congestion?

For example, you come up to a 4-way intersection and a traffic cop there signals you to stop and says you can't go through because all the man-hole covers are off, but since you want to turn left you can go through the parking lot of the corner gas station to get onto the other road.

For another example, right after the st-patrick's day parade is over or right after the college town's team has just won the NCAA championship, the street is full of people and the car has to inch forward at a rate of half of a mile per hour and the pedestrians don't get out of the way until the car is about to touch them.

In the scenarios you described, a remote operator would "help" the car. They've specifically said remote operators can't control or joystick the car, but can "answer questions" which I take it to mean plot a different course. It can also pull over at a safe spot and not get stuck in the middle of an intersection, though nobody has run into this issue to test it from the videos I've watched.

The examples you gave sound like scenarios where remote operator would instruct "don't go there, go here" and the car does it by itself. But specifically about the traffic cop, it can actually detect hand signals from them (can't find the video though).

> since you want to turn left you can go through the parking lot

In my state this is explicitly illegal. You may not use a parking lot as a thoroughfare, regardless of convenience.