L1-L4 don't inherently have anything to do with safety or anything else. They're simply terms to define different divisions of responsibilities between humans a

L1-L4 don't inherently have anything to do with safety or anything else. They're simply terms to define different divisions of responsibilities between humans and computers while driving. L5 mostly exists to have a term for "it's a computerized chauffeur without caveats". An L4 system with shitty safety metrics is still L4, simply unsafe. Likewise, a superhumanly safe L4 system still isn't L5. The whole level system isn't applicable to humans, except that humans are almost universally as capable as hypothetical L5 systems by definition.