MO Rev Stat § 304.019 (2021)
2021 Missouri Revised Statutes|Title XIX - Motor Vehicles, Watercraft and Aviation|Chapter 304 - Traffic Regulations|Section 304.019 - Hand and mechanical signals, violations, penalty.

Effective - 28 Aug 1996   304.019. Hand and mechanical signals, violations, penalty. — 1. No person shall stop or suddenly decrease the speed of or turn a vehicle from a direct course or move right or left upon a roadway unless and until such movement can be made with reasonable safety and then only after the giving of an appropriate signal in the manner provided herein.  (1) An operator or driver when stopping, or when checking the speed of the operator's vehicle, if the movement of other vehicles may reasonably be affected by such checking of speed, shall extend such operator's arm at an angle below horizontal so that the same may be seen in the rear of the vehicle;  (2) An operator or driver intending to turn the operator's vehicle to the right shall extend such operator's arm at an angle above horizontal so that the same may be seen in front of and in the rear of the vehicle, and shall slow down and approach the intersecting highway as near as practicable to the right side of the highway along which such operator is proceeding before turning;  (3) An operator or driver intending to turn the operator's vehicle to the left shall extend such operator's arm in a horizontal position so that the same may be seen in the rear of the vehicle, and shall slow down and approach the intersecting highway so that the left side of the vehicle shall be as near as practicable to the center line of the highway along which the operator is proceeding before turning;  (4) The signals herein required shall be given either by means of the hand and arm or by a signal light or signal device in good mechanical condition of a type approved by the state highway patrol; however, when a vehicle is so constructed or loaded that a hand and arm signal would not be visible both to the front and rear of such vehicle then such signals shall be given by such light or device. A vehicle shall be considered as so constructed or loaded that a hand and arm signal would not be visible both to the front and rear when the distance from the center of the top of the steering post to the left outside limit of the body, cab or load 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 thereon exceeds fourteen feet, which limit of fourteen feet shall apply to single vehicles or combinations of vehicles. The provisions of this subdivision shall not apply to any trailer which does not interfere with a clear view of the hand signals of the operator or of the signaling device upon the vehicle pulling such trailer; provided further that the provisions of this section as far as mechanical devices on vehicles so constructed that a hand and arm signal would not be visible both to the front and rear of such vehicle as above provided shall only be applicable to new vehicles registered within this state after the first day of January, 1954.  2. Violation of this section shall be deemed a class C misdemeanor. ­­-------- (L. 1953 p. 587 § 304.020, A.L. 1996 H.B. 1047)  (1954) Where plaintiff admittedly did not give hand signal of his intention to stop, and other evidence was to the effect that no electric stop signal was seen, question of contributory negligence in failing to give warning of stop held for jury even though car was equipped with adequate electrical signaling devices. White v. Rohrer (Mo.), 267 S.W.2d 31. (1958) Under the circumstances of the case, whether defendant was guilty of negligence in failing to give signal of intention to turn right at driveway was question for jury. Ilgenfritz v. Quinn (Mo.), 318 S.W.2d 186. (1959) Where driver gave timely and adequate signal of intention to stop by means of a stop light on left rear of vehicle operated off of the brake, he was not required to give hand signal. Pilkenton v. Fegley (Mo.), 321 S.W.2d 435. (1961) Section 304.019 is not limited to cases where there is a sudden checking of speed but the degree of abruptness would have a decided bearing upon whether it would reasonably affect the movement of a following vehicle. Lafferty v. Wattle (A.), 349 S.W.2d 519. (1964) A motorist who intends to turn left may not assume that other vehicles will not be on the highway in violation of rules of the road and must make proper observation to rear to see that another vehicle is not coming into such close proximity that a left turn cannot be made with reasonable safety and must give appropriate signal of intent to turn left. Reed v. Shelly (A.), 378 S.W.2d 291. (2004) Signal requirement does not apply to vehicles moving from stopped position and entering traffic; probable cause did not therefore exist for police officer to stop vehicle after defendant pulled vehicle onto street from parked position without signaling. State v. Johnson, 148 S.W.3d 338 (Mo.App.W.D.).