Reports must be filed in connection with any accident involving an injury, death or property damage in excess of $1,500 ($500 if there is no insurance coverage). See 625 ILCS 5/11-406 (from Ch. 95 1/2, par. 11-406).
625 ILCS 5/11-408 states in relevant part:
Every law enforcement officer who investigates a motor vehicle accident for which a report is required by this Article or who prepares a written report as a result of an investigation either at the time and scene of such motor vehicle accident or thereafter by interviewing participants or witnesses shall forward a written report of such motor vehicle accident to the Administrator on forms provided by the Administrator under Section 11\u2011411 within 10 days after investigation of the motor vehicle accident, or within such other time as is prescribed by the Administrator.
Sec. 11-406. Duty to report accident.
(a) The driver of a vehicle that is in any manner involved in an accident within this State, resulting in injury to or death of any person, or in which damage to the property of any one person, including himself, in excess of $1,500 (or $500 if any of the vehicles involved in the accident is subject to Section 7\u2011601 but is not covered by a liability insurance policy in accordance with Section 7\u2011601) is sustained, shall, as soon as possible but not later than 10 days after the accident, forward a written report of the accident to the Administrator.