N.M. Stat. Ann. § 66-7-304
A. The board of county commissioners of a county may alter and establish speed limits lower than those established by law on county roads within its county, provided that:
History: 1953 Comp., § 64-7-304, enacted by Laws 1978, ch. 35, § 408; 2003, ch. 142, § 14.
Cross references. — For the adoption of a manual and specifications for a uniform system of traffic-control devices, see 66-7-101 NMSA 1978.
The 2003 amendment, effective July 1, 2003, added "deemed to be" preceding "reasonable" in Paragraph A(1) and substituted "transportation commission" for "highway commission" in Paragraphs A(2), A(3) and Subsection B.