Law-enforcement officers and uniformed school crossing guards may direct traffic by signals. Such signals other than by voice shall be as follows: 1. To stop traffic by hand. — Stand with shoulders parallel to moving traffic. Raise arms forty-five degrees above shoulder with hand extended, palm towards moving traffic to be stopped. 2. To move traffic by hand. — Stand with shoulders parallel to traffic to be moved. Extend right arm and hand full length at height of shoulders towards such traffic, fingers extended and joined, palm down. Bring hand sharply in direction traffic is to move. Repeat movement with left arm and hand to start traffic from opposite direction. 3. To stop and start traffic by whistle. — One blast, moving traffic to stop; two blasts, traffic in opposite direction to move. 4. Emergency stop of traffic by whistle. — Three or more short blasts, all traffic shall immediately clear the intersection and stop. Such law-enforcement officers and uniformed school crossing guards may also use supplemental traffic direction devices, including but not limited to hand-held stop or go signs, in directing traffic as provided in this section.