Ind. Code § 6-6-4.1-4
(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:
(3) When imposed upon the consumption of a natural gas product or an alternative fuel, the tax rate is either of the following:
(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.
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.
(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.