The provisions of this act shall apply in all cases where the improvement of a highway had been petitioned for under the provisions of chapter 265 [*], Laws of Kansas of 1917, or chapter 246 [*], Laws of Kansas of 1919, amendatory thereto, but which projects had not been completed prior to the taking effect of this act. This act shall apply to all petitions heretofore signed, but not filed or granted under the provisions of acts above mentioned.