Texas Transportation Code - TRANSP § 545.107. Method of Giving Hand and Arm Signals

(1) to make a left turn signal, extend hand and arm horizontally;

(2) to make a right turn signal, extend hand and arm upward, except that a bicycle operator may signal from the right side of the vehicle with the hand and arm extended horizontally; and

(3) to stop or decrease speed, extend hand and arm downward.