(a) Except as provided in subsection (c) of this section, every driver's license expires eight years from the date of its issuance.
(b)(1) Every driver's license issued to a person who has attained his or her twenty-first birthday expires on the licensee's birthday. The commissioner may modify the expiration date of any license as necessary to effectuate the transition from the five-year renewal cycle to an eight-year renewal cycle as he or she considers necessary.
(2) Every driver's license issued to a person who has not attained his or her twenty-first birthday expires thirty days after the licensee's twenty-first birthday, except as provided in section three-a of this article.