I've found New York State figures.[1] But they don't have a breakdown by fatal/nonfatal. Like the UK data, they show much lower accident rates on divided, limited access highways.

California has a fatality rate of 0.94 per 100 million miles traveled.[2] That's lower than the US average. But it's not broken down by freeway/non freeway. (You can request a login to query the database directly and download data, and it might be possible to compute freeway accident rates.)

[1] https://www.dot.ny.gov/divisions/operating/osss/highway-repo... [2] https://www.chp.ca.gov/programs-services/services-informatio...

His point was not to compare US and UK.

His point was that miles driven on freeway (when you are using Tesla's autopilot) seems less dangerous than miles driven everywhere else.

He found the UK data and wonders if the same applies to the US. The implication is that if it did, then Tesla would be comparing apples with oranges in its 100m miles reference.