If the commissioner does not take over the highway in the manner prescribed in section 27:9-3 of this title within six years after the authorization of the appropriation for its construction and improvement, the county shall refund the indebtedness incurred pursuant to section 27:9-2 of this title by the issuance of bonds under the provisions of article 1 of chapter 1 of the title Municipalities and Counties (s. 40:1-1 et seq.), none of which shall mature at a date later than the period set forth in section 40:1-34, of the title Municipalities and Counties, counting from the time of the authorization of the appropriation for the construction and improvement.