New York Consolidated Laws, Vehicle and Traffic Law - VAT § 1684. State highways maintained by the state

No local authority shall place or maintain any traffic-control device on any state highway maintained by the state, or at any location so as to prohibit, restrict or limit the movement of traffic proceeding along, entering or crossing such highway, nor shall any ordinance, rule or regulation affecting traffic or stopping, standing or parking on state highways maintained by the state be effective unless or until approval in writing has been obtained from the department of transportation, and the department of transportation may at any time rescind or modify such approval.