The city shall pay such part of the cost and expense of improvements for which special assessments are levied as the commission deems just which part shall not be less than one-fiftieth (1/50) of all such cost and expense; and in addition thereto the city shall pay the cost of intersections. The commission may provide for the payment of the city’s portion of all such improvements by the issuance of bonds or notes therefor, and may levy taxes, in addition to all other taxes authorized by law, to pay such bonds or notes and the interest thereon.