(b) Any motor vehicle in use on a highway shall be equipped with,  and
required  signal  shall be given by, signal lamps when the distance from
the center of the top of the steering post to the left outside limit  of
the body, cab, or load of such motor vehicle exceeds twenty-four inches,
or  when the distance from the center of the top of the steering post to
the rear limit of the body or load thereof exceeds  fourteen  feet.  The
latter  measurement  shall  apply  to  any  single  vehicle, also to any
combination of vehicles. On a combination of vehicles, the  rear  signal
lamps  shall  be at the rear of the last vehicle in the combination. The
provisions of this subdivision shall not apply to a vehicle, alone or in
combination with other vehicles or implements, if such vehicle  is  used
solely  for  agricultural  purposes,  and  is  not designed and intended
primarily for use on the highway, or to fire  vehicles,  or  to  special
purpose  commercial  motor  vehicles  registered  under  schedule  F  of
subdivision seven of section four hundred one of this chapter.
Structure New York Laws
Article 28 - Turning and Starting and Signals on Stopping and Turning
1160 - Required Position and Method of Turning at Intersections.
1161 - U Turns in Certain Areas Prohibited.
1162 - Starting Parked Vehicle.
1163 - Turning Movements and Required Signals.
1164 - Signals by Hand and Arm or Signal Lamps.