IMO it's not necessarily unreasonable to use standards/evaluations set by a private industry group for this kind of thing.

US automobile safety ratings/improvements over time are largely driven by IIHS (Insurance Institute for Highway Safety). It's a private group but is the standard yardstick manufacturers expect to be tested against and fills in a lot of gaps in NHTSA official crash tests.

It wouldn't be strange to see IIIS plus NHTSA criteria used colloquially to describe "US crash standards" when talking about cars even if not fully defined by regulation.

"UL Listed" products or the International Building Code (the base model broadly followed with modifications by each state) are also "national standards" but not set by regulation.