70 ILCS 3715/16

In all actions for the violation of any ordinance of the authority, the first process shall be a summons or a warrant. A warrant for the arrest of an accused person may issue upon the affidavit of any person that an ordinance has been violated, and that the person making the complaint has reasonable grounds to believe that the party charged is guilty thereof. Every person arrested upon a warrant shall be taken, without unnecessary delay, before the proper officer for examination.

The person upon whom any fine or penalty is imposed, upon the order of the court may be committed to any place lawfully provided by ordinance for the incarceration of offenders until the fine, penalty, and costs are fully paid where failure to pay is wilful. No imprisonment, however, shall exceed 30 days if the fine is imposed for a petty offense, business offense, or misdemeanor, or 6 months if the fine is imposed for a felony.