Oczywiście pominąłeś najważniejsze kwestie czyli:

highway=unclassified is used for minor public roads, typically at the lowest level of administrative hierarchy in that jurisdiction.

Unclassified roads are public roads usable by motor cars that are less important than tertiary roads. Unlike residential and track, they are generally outside of residential areas and are not primarily used for agriculture. They can connect small hamlets; remote industry such as power plants or oil fields; wilderness areas; minor ski centers; and similar features requiring infrequent car access.

Co do "Usually, they are designed for local traffic, but may sometimes be used as a detour or a shortcut for through traffic." masz napisane, że 'usually', a definicja kategorii się różni między krajami, jak wiesz bardzo dobrze.

Ale to nijak się ma do tej sytuacji. Również sposób, w jaki przedstawiłeś definicję, pokazuje, że tutaj zupełnie nie pasuje unclassified.