I’m thinking of using the term indigenous instead of natural to describe the existing infrastructure of a city prior to the construction of any bike-specific facilities. The OED defines indigenous as “Originating or occurring naturally in a particular place,” which I think captures the idea I want to get across. Indigenous bikeways aren’t entirely natural, but they exist (or don’t) based on decisions that were made decades or centuries ago.
The term also has a slightly unsettling connection to colonialism which I actually think is good, because I think urbanism often has a slightly unsettling connection to colonialism, or more specifically Orientalism.
And I happened to be visiting a city named for America’s favorite colonialist.