Highways rack up a lot of miles, but is a really easy environment to drive in. Intersections, pedestrian crossings, busy streets, parking etc don't yield a lot

Highways rack up a lot of miles, but is a really easy environment to drive in. Intersections, pedestrian crossings, busy streets, parking etc don't yield a lot of miles to the statistics, but is where most interaction with other people, and most edge cases show up. So I'm not sure that accidents per mile is necessarily the best metric either.