[masklinn]

Doesn't look like it:

> Swiss Re has more than 500,000 liability claims and more than 200 billion miles of exposure in its data bank. Waymo has logged 25.3 million fully autonomous miles available for analysis as well.

So looks like they took human-driven miles in all sorts of conditions, and compared it to Waymo's operation in a handful of southern states.

Although I would expect not using highways to be detrimental, statistically highways (especially controlled access highways) are the road types with the highest safety levels, thanks to having no intersections, more consistent speeds, and traffic separation.