Wis. Stat. § 182.46: Tax exemptions.

The exercise of the powers granted by ss. 182.30 to 182.48 will be in all respects for the benefit of the people of this state, for the increase of their commerce and prosperity and for the improvement of their health and living conditions. Therefore the corporation shall not be required to pay any taxes or assessments upon any turnpike project or any property acquired or used by the corporation under the provisions of ss. 182.30 to 182.48 or upon the income therefrom, and the bonds issued under the provisions of ss. 182.30 to 182.48, their transfer and the income from the bonds, including any profit made on the sale of the bonds, shall at all times be free from taxation within this state.