Indiana Code Title 8. Utilities and Transportation § 8-14-9-13

Sec. 13. For the purpose of raising money to pay bonds issued under section 10 of this chapter as the bonds severally mature, and to pay all interest accruing on the bonds, the county council of a qualified county may, notwithstanding IC 8-18-8-5, impose a special tax on all real and personal property located within the local county road and bridge district.  However, the county council may only impose a tax under this section for a particular budget year to the extent that the estimated revenues that the county will receive from the county vehicle excise tax and the county wheel tax during that budget year will be insufficient to pay the principal and interest coming due on those bonds during that budget year.  The special tax constitutes the amount of benefits to the property which result from carrying out a project under this chapter.