Level 5 means there is no instance when Waymo intervenes from home base to tell the car what to do to get around an obstacle, and no instance where an emergency responder drives the car to move it out of the way. If the car is told to take the passengers to Arrowhead stadium, and it is directed verbally by stadium staff to go to parking lot 3, it goes to parking lot 3. Waymo will probably roll out level 4 robotaxis to a major city soon, but it's very hard to see them getting to level 5.

Emergencies are noted exceptions to Level 5, so the "A first responder insists on driving the car" case is still level 5.

Waymo has level 4 taxis in two US cities and is running tests elsewhere too. The usual reaction from the "This can't be done because somehow driving a motor vehicle is a uniquely human ability" people in those cities seems to be head-in-the-sand refusal to believe. The good news is that if they choose to believe a Waymo doesn't exist and step in front of it, it'll probably brake politely to a halt like they're any other asshole.

Level 5 mostly requires more range. I don't think this bet is a sure thing, but it's certainly possible that Waymo's reason you can't go from say New York City to Birmingham Alabama in 2030 is something that sounds like a taxi company reason rather than an "Our AI can't do that" reason.