PJ Vogt

His name is Timothy B. Lee, author of the newsletter Understanding AI.

I asked him how much our picture of the Waymo safety data has been evolving.

So it's been pretty consistent the last couple of years.

They are scaling up.

And so all the numbers get bigger, like the total number of miles get bigger, the number of crashes get bigger.

But the light crashes per mile have not changed a ton.

Waymo says, and I think this is correct, that it's roughly 80% safer in terms of crashes that are severe enough to trigger an airbag, crashes severe enough to cause an injury, and also crashes involving vulnerable road users like pedestrians or bicyclists.

So 80% fewer airbag crashes than human drivers, and actually 90% fewer crashes that cause a serious injury.

Some independent experts have small quibbles with the methodology, but broadly they find Waymo's data credible.

Timothy pointed out there's one very important thing we don't know, the fatal crash comparison.

For every 100 million miles humans drive, we cause a little over one fatal crash.

The Waymo driver has driven 200 million miles without causing a fatal crash.

But statistically speaking, that could still be a fluke.

Some academics have suggested we'd need about 300 million miles to have statistical confidence.

In the hundreds of millions of miles the Waymo driver has traveled, it was involved in two fatal crashes which it did not appear to cause.

Here are the details of those crashes.

In one, a speeding human driver rear-ended a line of vehicles at a stoplight.

There's an empty Waymo in the line of struck cars.

In another crash, a Waymo was yielding for a pedestrian.

It was rear-ended by a motorcycle.