Idaho Code § 40-321

No commercial enterprise or activity for serving motor vehicle users, other than emergency services for disabled vehicles and vending machines permitted under the provisions of federal law or federal rule and section 67-5411, Idaho Code, and board right-of-way use permit shall be conducted within or on any property designated as, or acquired for, or in connection with a prohibited access highway, as designated by the Idaho transportation board. However, the board may construct on that property, at locations it deems appropriate, connecting service highways parallel to the prohibited access highways in such manner as to facilitate the establishment and operation of commercial enterprises for serving motor vehicle users on private property abutting those service highways.