The city finance department of a city of the metropolitan class shall establish and maintain a fund to be designated fund to finance intersections. Immediately upon the completion of the work of any contract for improvements authorized by this section, the city engineer shall estimate and certify to the city council the amount which has been spent in the performance of such contract for proper intersection purposes. The city council shall at once examine such certification and either approve or reject the amount so certified. If such certification is rejected, further certifications shall be required until a proper amount has been certified, which shall be approved. As soon as approved, the city finance department shall charge the special assessment sinking fund with the full amount as approved and shall credit the fund to finance intersections with a like amount. Just before each interest payment date an account shall be correctly and exactly stated between such funds so as to apportion as properly and exactly as possible the respective interest charge against each fund. Both such funds shall be continuously kept and maintained so that the fund to finance intersections will show exactly or approximately the total amount of bonds which has been devoted to the payment of intersection charges.