Idaho Code § 40-603: County highways recommended by commissioners — Approved by board.

The commissioners of each county shall recommend highways for the county highway system to the board at least once a year and in a manner and form to be prescribed by the board. All recommendations shall clearly show which highways are improved highways and which are unimproved. All recommendations must be approved by the board before they shall constitute the official highway system of the county. The board may require commissioners to submit financial and operating data as it may deem necessary to assist it in determining what highways should properly be included in the respective county highway systems.