All moneys received by treasurers of cities, towns and villages under this act [67-4-18, 67-4-19 NMSA 1978] shall be held and expended as "street paving and improvements funds," and for no other purposes, providing that all funds received hereunder shall be expended for street maintenance and improvement of streets in such cities, towns and villages which are extensions of the public roads and highways through or into such cities, towns and villages and that paving shall not be considered as improvements for the purposes of this act.
And provided further that such funds may be expended upon roads within the county outside of the limits of and leading into such cities, towns and villages.
NMS § 67-4-19