Ill. Admin. Code tit. 92, § 3000.1360
d) Petition for appeal shall detail the assailed findings and be confined to factual and legal issues which are essential to the ultimate and just determination of the proceeding. Petitions shall not exceed 10 pages in length, excluding a separate preface and summary of argument which shall not exceed 3 pages. A reply to the petition, if any, shall be filed within 20 days of receipt of the petition for appeal and shall meet the same requirements as to length and format.
(Recodified from 92 Ill. Adm. Code 107 (Department of Transportation) pursuant to P.A. 104-0025, at 49 Ill. Reg. 12509)