(a) With the board of supervisors, or other legislative body, of the county in which such town is located, together with the written recommendations of the county superintendent.

(b) With the commissioner, together with a copy of the resolution of approval of such county board of supervisors or legislative body. 2. The commissioner, after investigation, may approve such plan or the plan of any separate project thereof for execution as appropriations therefor may be available or may disapprove any such plan and shall immediately notify the town board of such approval or disapproval. If any such plan be disapproved, the commissioner shall immediately return such plan to the town board with his reasons for disapproval and suggestion for modification of the plan and shall notify the board of supervisors and county superintendent of such action. Modification of a disapproved plan shall be made and filed in like manner. 3. A copy of such plan, when prepared and approved as herein provided, together with copies of the approval of the commissioner and the board of supervisors, shall be filed in the office of the clerk of the town in which such highway is located, in the office of the county clerk and county superintendent of the county in which such town is located. The copy transmitted to the commissioner shall be retained by him. 4. The statement of necessity required as a part of the plan for a project shall set forth the reasons why such improvement, repair or reconstruction is necessary adequately to serve permanent agricultural, residential, commercial or industrial development and to sustain the vehicular load imposed or likely to be imposed on such town highway. 5. Modification of any plan approved as herein provided may be made by the town board of the town affected thereby and must be filed and approved in the manner hereinbefore provided for the filing and approval of an original plan, except that the approval of the county board of supervisors, or other legislative body, of the county in which such town is located shall not be required. The commissioner may refuse to approve the modification of the plan of any project unless the modification is filed in his office prior to September first of the calendar year preceding that for which the project has been approved. Any modification must be recommended on or before April first, nineteen hundred eighty. 6. No meeting of the town board shall be held for the purpose of adopting or modifying a plan, unless the town and county superintendent of highways shall be notified thereof. 7. If a town has not adopted and filed a plan as above provided in the section, it may adopt and file a plan in the manner set forth in this section on or before July first in any year covering all projects contemplated during the remaining years of the period of the duration of this article. In such event the provisions of this article shall apply as if the plan originally had been filed in the manner provided in this section.