No vehicle standing at or along the curb or side of any street shall start or turn from such curb or side of the street until the driver shall have given a signal which can be plainly seen from the rear of such vehicle and from the side toward which he or she is about to turn, which signal shall be by signal lights or by extending the left arm to the left of and beyond the vehicle, with the hand and forearm extending horizontally and at right angles to the vehicle.