Any town adopting the provisions of sections 13a-8 to 13a-11, inclusive, may appoint a superintendent of highways and bridges. Within thirty days after the adoption of said sections by any town having a board of finance, and triennially thereafter, such board of finance, at a meeting called and held by it, shall, by a majority vote, nominate to the selectmen of such town two or more persons for the office of superintendent of highways and bridges. The selectmen shall, within ten days from the date of such nomination, from the list of nominees, appoint a superintendent of highways and bridges for such town to hold office for three years from the first Monday of October next succeeding his appointment. Within thirty days after the adoption of said sections by any town not having a board of finance, and triennially thereafter, the selectmen shall appoint a superintendent of highways and bridges for such town to hold office for three years from the first Monday of October next succeeding his appointment. The superintendent of highways and bridges may be removed from office by the selectmen on charges preferred by a majority vote of the board of finance or by the selectmen where no board of finance exists, after notice to such superintendent and hearing upon such charges. In case of the removal of such superintendent from office, a successor for the unexpired portion of the term may be appointed by the selectmen or by the selectmen on nomination of the board of finance in the manner hereinbefore provided.