(a) A tax is imposed on the consumption of motor fuel by a carrier in its operations on highways in Indiana. The rate of this tax is determined as follows:

1. (1) When imposed upon the consumption of special fuel (other than an alternative fuel or a natural gas product), the tax rate is the same rate per gallon as the rate per gallon at which special fuel is taxed under IC 6-6-2.5 .
2. (2) When imposed upon the consumption of gasoline, the tax rate is the same rate per gallon as the rate per gallon at which gasoline is taxed under IC 6-6-1.1 .

3. (3) When imposed upon the consumption of a natural gas product or an alternative fuel, the tax rate is one (1) of the following:

   1. (A) The same rate per diesel gallon equivalent as the rate per gallon at which special fuel is taxed under IC 6-6-2.5 , in the case of liquid natural gas.
   2. (B) The same rate per gasoline gallon equivalent at which special fuel is taxed under IC 6-6-2.5 , in the case of compressed natural gas or an alternative fuel commonly or commercially known or sold as butane or propane.

   3. (C) The same rate per gallon equivalent at which special fuel is taxed under IC 6-6-2.5 , in the case of an alternative fuel not commonly known or sold as butane or propane, divided by:

      1. (i) the carrier's average miles per gallon for all vehicles in the fleet that consume motor fuels described in subdivision (1), if the fleet has both vehicles that consume motor fuels described in subdivision (1) and vehicles that consume alternative fuels that are not commonly or commercially known or sold as butane or propane; or

      2. (ii) the carrier's average miles per gallon for the preceding quarter of Indiana based International Fuel Tax Agreement vehicles consuming motor fuels described in subdivision (1), if all vehicles in the fleet consume an alternative fuel that is not commonly or commercially known or sold as butane or propane.

         The tax shall be paid quarterly by the carrier to the department on or before the last day of the month immediately following the quarter. The department shall publish on its website each quarter the average miles per gallon for the preceding quarter for a vehicle described in subdivision (3)(C)(ii).

(c) The amount of tax that a carrier shall pay for a particular quarter under this section equals the product of the tax rate in effect for that quarter, multiplied by:

1. (1) except as provided in subdivision (2), the amount of motor fuel consumed by the carrier in its operation on highways in Indiana and upon which the carrier has not paid tax imposed under IC 6-6-1.1 , IC 6-6-2.5 , or section 4.5 of this chapter (before its repeal); or
2. (2) the miles traveled on highways in Indiana for an alternative fuel that is not commonly or commercially known or sold as butane or propane.

(d) Subject to section 4.8 of this chapter, a carrier is entitled to a proportional use credit against the tax imposed under this section for that portion of motor fuel used to propel equipment mounted on a motor vehicle having a common reservoir for locomotion on the highway and the operation of the equipment, as determined by rule of the commissioner. An application for a proportional use credit under this subsection shall be filed on a quarterly basis on a form prescribed by the department.

As added by Acts 1982, P.L.59, SEC.1. Amended by P.L.90-1983, SEC.1; P.L.77-1985, SEC.27; P.L.59-1985, SEC.16; P.L.97-1987, SEC.38; P.L.69-1991, SEC.12; P.L.277-1993(ss), SEC.46; P.L.85-1995, SEC.31; P.L.222-1999, SEC.3; P.L.277-2013, SEC.12; P.L.218-2017, SEC.46; P.L.185-2018, SEC.7; P.L.234-2019, SEC.23; P.L.211-2023, SEC.4.