Indiana Code Title 8. Utilities and Transportation § 8-1-13-36

Sec. 36. Upon a complaint made against any corporation by:

that any of the rates, tolls, charges, schedules, or joint rates (with which the petitioner is directly interested) are in any respect unreasonable or unjustly discriminatory, or that any regulation, measurement, practice, or act affecting or relating to the service of a corporation is in any respect unreasonable, unsafe, insufficient, or unjustly discriminatory, or that any service is inadequate or cannot be obtained, the commission shall proceed to investigate with or without notice.  However, the commission may not enter an order affecting those rates, tolls, charges, schedules, regulations, measurements, practices, or acts complained of without a formal public hearing.