93. (1) The driver of a motor vehicle with a right hand steering control shall on the occasions specified in the Eleventh Schedule make the signals specified therein: Provided that the signal of an intention to turn to the right or left or to stop may be given by a mechanical or an electrical device of a prescribed nature affixed to the vehicle. (2) In the case of a motor vehicle with a left hand steering control the signal of an intention to turn to the right or left or to stop shall be given by a mechanical or an electrical device of a prescribed nature affixed to the vehicle, and in case of sudden failure of the devices, the signal shall, however, be given with the left hand.