605 ILCS 5/9-129
Agricultural aircraft used for crop dusting or other activities in aid of agriculture as authorized by the Division of Aeronautics of the Department of Transportation may use any county highway or township road as defined under Sections 2-204 and 2-205 of this Code, if granted permission by the County Superintendent of Highways or the Highway Commissioner, whoever shall have proper jurisdiction over such road. Permission to use county highways or township roads shall only be granted by the County Superintendent of Highways or the Highway Commissioner if the average daily traffic count is less than 200. Roads used by agricultural aircraft shall be blocked by barricades conforming to the Manual of Uniform Traffic Control Devices adopted by the Department and shall be accompanied at all times, while in place upon such road, by a flagman. All barricades and flagmen shall be furnished by any individual applying for permission to use any such roads for agricultural aircraft. Traffic shall not be delayed by the use of a county highway or township road by agricultural aircraft by more than 15 minutes in each 30 minute period, and no emergency vehicle shall be delayed at any time unless the safety of either the plane or emergency vehicle would be seriously threatened if the emergency vehicle were allowed to proceed.
A county, county superintendent of highways, township or township commissioner shall not be liable for any personal injuries caused as a result of the operation of agricultural aircraft on such highways.
605 ILCS 5/9-129