Being satisfied that the petitioners are responsible and that an inquiry into the merits is expedient, the county commissioners shall cause 30 days' notice to be given of the time and place of their meeting by posting copies of the petition, with their order thereon, in 3 public places in each town in which any part of the way is, by serving one on the Department of Transportation and serving one on the clerks of such towns and publishing it in some newspaper, if any, in the county. The fact that notice has been so given, being proved and entered of record, shall be sufficient for all interested, and evidence thereof.   [PL 1971, c. 593, §22 (AMD).]