The exercise of powers for turnpike projects shall be in all respects for the benefit of the people of the state, for the increase of their commerce and prosperity, and the improvement of turnpike projects by the board shall constitute the performance of essential governmental functions. The board shall not be required to pay any taxes or assessments upon any turnpike project or any property acquired or used by it relating to turnpike projects or upon the income from them, and any turnpike project and any property acquired or used by the board, and the income from them, and the bonds issued, their transfer and the income from them, including any profit made on the sale of them, shall be exempt from all taxation.
Idaho Code § 40-408