Maryland Code, Transportation § 21-902.3

(a) In this section, “test” has the meaning stated in § 16-205.1 of this article.

(b) If a person is convicted of a violation of § 21-902(b) or (c) of this subtitle and the trier of fact finds beyond a reasonable doubt that the person refused to take a test arising out of the same circumstances as the violation, the court shall require the person to participate in the Ignition Interlock System Program under § 16-404.1 of this article for 1 year.

(c) The penalty provided under this section shall be:

(d) If a person subject to this section participates in the Ignition Interlock System Program under § 16-205.1 of this article, the person shall receive credit toward the length of participation in the Ignition Interlock System Program arising out of the same incident required under this section.