23 CFR § 1215.4 - Compliance criteria.
(a) Except as provided in paragraphs (c) or (d) of this section, in order to avoid the transfer or reservation (as applicable) specified in § 1215.7, a State must have and continue in effect at all times during the fiscal year a law which makes unlawful throughout the State the operation of a passenger vehicle whenever an individual in a front seat of the vehicle (other than a child who is secured in a child restraint system) does not have a safety belt properly fastened about the individual's body.
(b) A State that enacts the law specified in paragraph (a) of this section will be determined to comply with 23 U.S.C. 153, provided that any exemptions are consistent with § 1215.5.
(c) If New Hampshire or Maine enacts a law described in paragraph (a) of this section by January 27, 1996, the State shall be deemed as having that law in effect on September 30, 1995.
(1) If the Secretary certifies in a fiscal year that New Hampshire or Maine has achieved the safety belt use rate specified in paragraph (d)(2) of this section, the State shall be considered as complying with the provisions of paragraph (a) of this section.
(2) The safety belt use rate must be not less than 50 percent in each of fiscal years 1995 and 1996, and not less than the national average as determined by the Secretary in each fiscal year thereafter.