Section 5. If at the time of the view or hearing as provided in section three when a plan has been prepared no person interested objects, the commissioners may, within twelve months thereafter, lay out, alter, relocate, or order specific repairs upon such highway without further notice. If at such time any person interested objects, the commissioners shall not lay out, alter, relocate, or order specific repairs upon such highway without another hearing, at which any party interested may be heard with respect to the manner in which the proposed improvement shall be carried out. Notice of such hearing shall be given in the manner prescribed in section three. If at the time of a view upon a petition for discontinuing or discontinuing maintenance of a highway, the commissioners decide that it ought to be discontinued or no longer maintained, they may at the same time adjudge that it be discontinued or no longer maintained, without a further or subsequent meeting therefor; and if a return of said proceedings and adjudication is made and accepted at the next regular meeting of the commissioners, it shall be a discontinuance or discontinuance of maintenance of such highway. The commissioners may adjudicate and decree in respect to a portion of a way described in a petition pending before them, leaving the petition open pending a further or final adjudication and decree in respect to a further portion of said way or a final adjudication and decree as to the remainder of such way. Upon petition of a town or city, the commissioners may discontinue a county highway and thereafter the way or section of way so discontinued shall be a town way. Unless so petitioned, the discontinued way shall no longer be a public way.