65 ILCS 5/11-42-12

They may require that the owner of a parking garage, lot or ramp post a bond in an amount established by ordinance to assure the payment of any damages to vehicles while under the control of a parking garage, lot or ramp. The words "parking garages, lots and ramps" as herein used do not include private parking garages, lots and ramps operated for the sole use of the owner, his employees, agents, and customers.