Conn. Gen. Stat. § 13a-43

The commissioner may, in connection with a new highway constructed in a town, abandon any highway, or section or appurtenance thereof, in the state highway system no longer conforming with the definitions set out in section 13a-14 or no longer serving the best interest of the state as a part of the state highway system, upon notice to the board of selectmen of the town wherein such highway, or section or appurtenance thereof, is located, and such highway, or section or appurtenance thereof, shall revert to the town unless legally abandoned by it. Before abandonment of any part of the state highway system, the commissioner shall put the same in reasonably good condition, except where the same is no longer useful or necessary for highway purposes. Any town aggrieved by the abandonment of any part of any road, or section or appurtenance thereof, may elect to submit the matter to arbitration as provided in section 13a-17 .