No, the only way to know how well it's doing is for it to get enough "interesting" miles, and then compare the success rate of those miles to similar human-driven miles. Right now Waymo is past 8 million miles driven. Miles driven is a better and normalized metric, with comparable real world statistics, unlike time.
Miles driven is a less valuable number if the miles are largely along "easy" paths. What interests me is challenging events, perhaps what you call "interesting miles" because the more of those that cars successfully navigate, the more real-world ready the autonomous vehicles will be. There are hundreds of different types of these situations that are common enough that these vehicles will have to react appropriately (construction, detours, officer using hand signals, missing or misleading road paint, inaccurate maps, etc.) I don't know where Google's cars have driven, so they may have encountered these things, but I don't know.
I did explicitly say "interesting" miles, but we shouldn't mix up Phoenix miles with New York miles or Canada miles. No one claims they are ready to run anywhere in the world, but they have enough miles in Phoenix that they're confident they've seen almost all interesting miles there.
Waymo is past 8 million miles total, how many miles on the latest version of the software? Certainly there are new features that are there in the last half than the first half? I think miles count is a bad metric and if it wasn't, Tesla would be the front runner.
All those miles are recorded, fuzzed and replayed in simulation, where they've driven over 5 billion miles. I assume they retest all the miles + fuzzed versions on every version release.
It’s past 10 million miles and it’s driving more than 500k mi per month.
If the last version of the software was in August that it’s more than 2 million miles by now.
The miles per month figure will only increase.
And how many of those miles are up and down 101 after midnight on weekdays?