23 C.F.R. § 1275.4
(a) To avoid the reservation of funds specified in § 1275.6, a State must enact and enforce a repeat intoxicated driver law that establishes, as a minimum penalty, that all repeat intoxicated drivers:
(1) Receive, for a period of not less than one year, one or more of the following penalties:
(3) Except as provided in § 1275.5, receive a mandatory sentence of -
(b) Special exceptions. As used in paragraph (a)(1)(ii) of this section, special exception means an exception under a State alcohol-ignition interlock law for the following circumstances only: