N.Y. VAT Law § 1163

§ 1163. Turning movements and required signals. (a) No person shall\nturn a vehicle at an intersection unless the vehicle is in proper\nposition upon the roadway as required in section eleven hundred sixty,\nor turn a vehicle to enter a private road or driveway, or otherwise turn\na vehicle from a direct course or move right or left upon a roadway\nunless and until such movement can be made with reasonable safety. No\nperson shall so turn any vehicle without giving an appropriate signal in\nthe manner hereinafter provided.\n (b) A signal of intention to turn right or left when required shall be\ngiven continuously during not less than the last one hundred feet\ntraveled by the vehicle before turning.\n (c) No person shall stop or suddenly decrease the speed of a vehicle\nwithout first giving an appropriate signal in the manner provided herein\nto the driver of any vehicle immediately to the rear when there is\nopportunity to give such signal.\n (d) The signals provided for in section eleven hundred sixty-four\nshall be used to indicate an intention to turn, change lanes, or start\nfrom a parked position and not be flashed on one side only on a parked\nor disabled vehicle, or flashed as a courtesy or "do pass" signal to\noperators of other vehicles approaching from the rear.\n (e) The driver of a vehicle equipped with simultaneously flashing\nsignals as provided for in subdivision eighteen-a of section three\nhundred seventy-five shall use such signals when the vehicle is stopped\nor disabled on a public highway, except when such vehicle is stopped in\ncompliance with a traffic-control device or when legally parked. The\ndriver of a vehicle so equipped may use such signals whenever necessary\nto warn the operators of following vehicles of the presence of a traffic\nhazard ahead of the signaling vehicle, or to warn the operators of other\nvehicles that the signaling vehicle may itself constitute a traffic\nhazard, taking into account traffic and highway conditions. No person\nshall use such signals for any other purpose.\n