The Department of Public Works under the direction
of the Chief of Police shall install and maintain traffic control
devices under the provision of this chapter to make effective the
provisions of said chapter and shall install and maintain such additional
traffic control devices as the Board of Trustees may deem necessary
to regulate, warn or guide, traffic under the Vehicle and Traffic
Law of the State of New York subject to the provisions of §§ 1681,
1682 and 1684 of that law.