Ill. Admin. Code tit. 92, § 3000.1250
b) If, within 20 days after service of an order assessing a civil penalty, the respondent does not pay the civil penalty or file an appeal as provided in Section 107.323(a), the case shall be referred to the Attorney General with a request that an action to collect the penalty be brought in the appropriate Circuit Court.
(Recodified from 92 Ill. Adm. Code 107 (Department of Transportation) pursuant to P.A. 104-0025, at 49 Ill. Reg. 12509)