The Department of Public Works, in coordination
with the Police Department, shall install and maintain traffic control
devices when and as required under the provisions of this chapter,
to make effective the provisions of this chapter, and may install
and maintain such additional traffic control devices as it 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
§§ 1682 and 1684 of that law, as amended or changed.