Developer's Land
Section 10-30 of the Illinois Property Tax Code gives a preferential property assessment for acreage that is in transition from vacant land to a residential, commercial, or industrial use. The purpose of the preferential 
assessment is to encourage real estate development by providing a tax incentive that protects a developer from paying increased taxes until a return on investment can be made.
Publication 134
Public Act 96-480 (Temporary "developer's relief assessment")