The exercise of the powers granted by this act will be in all respects for the benefit of the people of the state, for the increase of their commerce and prosperity and for the improvement of their health and living conditions; and as the construction, improvement and reconstruction of highway projects in the state will constitute the performance of essential governmental functions, all bonds issued pursuant to the provisions of this act, and all income or interest therefrom, at all times shall be exempt from all state taxes.
K.S.A. 68-2309