Idaho Code § 50-1330

In a county with highway districts, the highway district board of commissioners in such district shall have exclusive general supervisory authority over all public streets and public rights of way under their jurisdiction within their district, excluding public streets and public rights of way located inside of an incorporated city that has a functioning street department, with full power to establish design standards, establish use standards and regulations in accordance with the provisions of title 49, Idaho Code, accept, create, open, widen, extend, relocate, realign, control access to or vacate said public streets and public rights of way. Provided, however, when said public street or public right of way lies within one (1) mile of a city, or the established county/city impact area or adjacent to a platted area within one (1) mile of a city or the established county/city impact area, consent of the city council of the affected city shall be necessary prior to the granting of acceptance or vacation of said public street or public right of way by the highway district board of commissioners.