The following signs are unlawful and a public nuisance:
Each sign declared by this Section to be unlawful and a public nuisance shall be removed or brought into compliance with this Act by the owner, without compensation, within 30 days after receipt of notice by certified mail from the Department, such notice period to be computed from the date of mailing. If the unlawful sign is affixed to a motor vehicle or a trailer or other vehicle capable of being propelled by a motor vehicle, it shall be removed by the owner, without compensation, within 24 hours after verbal notice by the Department. Any signs not so removed by the owners or any such signs which are removed and re-erected illegally by the owners shall become the property of the State and shall be removed and disposed of by the Department or may be painted over by the Department. The Department is also granted authority to enter upon private property for these purposes. If the name and address of the owner of the sign cannot be ascertained from the records of the Department or from a visual inspection of the sign foregoing notice provisions are not required and the Department shall take immediate action to remove or paint over the sign.
225 ILCS 440/10