Three main yardsticks: HH) fatalities per million passenger hours MM) fatalities per million passenger mile TT) fatalities per thousand trips.

I think MM records are more accurate, and data volume is much bigger. MM is more discussed, more reported in mass media, but I care more about HH.

https://turbli.com/blog/the-safest-transport-modes-ranked-by-statistics-from-10-years-of-data/

• uses both HH and MM
• explains “per passenger hour” is very different from “per vehicle hour”, and a much better yardstick