Subject to the limitations referred to in § 13a-198c and in order to effectuate the purposes of sections 13a-198a to 13a-198j, inclusive, the Commissioner of Transportation may (1) plan, design, lay out, construct, reconstruct, relocate, improve, maintain and operate the projects, and reconstruct and relocate existing highways, sections of highways, bridges or structures and incorporate or use the same, whether or not so reconstructed or relocated or otherwise changed or improved, as parts of such projects; (2) retain and employ consultants and assistants on a contract or other basis for rendering professional, legal, fiscal, engineering, technical or other assistance and advice; and (3) do all things necessary or convenient to carry out the purposes and duties and exercise the powers expressly given in sections 13a-198a to 13a-198j, inclusive. Except as otherwise stated in § 13a-198c, nothing contained in sections 13a-198a to 13a-198j, inclusive, shall be construed to limit or restrict, with respect to the projects, any power, right or authority of the Commissioner of Transportation existing under or pursuant to any other law.