N.M. Stat. § 66-7-327
Method of giving hand and arm signals.
All signals herein required given by hand and arm shall be given from the left side of
the vehicle in the following manner and such signal shall indicate as follows:
A. left turn: hand and arm extended horizontally;
B. right turn: hand and arm extended upward; and
C. stop or decrease speed: hand and arm extended downward.