If prior to the conclusion of the hearing written protests against the formation of the proposed improvement district and the proposed project signed by a majority in number of the holders of title to taxable property within the proposed improvement district and who are also the holders of title to not less than 51 percent of the area thereof are filed with the board, further proceedings relating to the proposed improvement district and the proposed project shall be terminated and no proceedings for the formation of any improvement district to undertake the proposed project shall be instituted for a period of not less than six months following the date of the conclusion of the hearing.