S.D. Codified Laws § 31-8-3

The highway authorities of the state, counties, and municipalities, acting alone or in cooperation with each other or with any federal, state, or local agency or any other state having authority to participate in the construction and maintenance of highways, may plan, designate, establish, regulate, vacate, alter, improve, maintain, and provide controlled-access facilities for public use wherever the authority is of the opinion that traffic conditions, present or future, will justify the special facilities. However, within a municipality that authority is subject to any municipal consent as may be required by law.