Indiana Code Title 8. Utilities and Transportation § 8-2.1-22-34

Sec. 34. (a) Every nonresident common carrier and contract carrier regulated under this chapter shall file, and keep on file, with the department a designation in writing of the name and postoffice address of a citizen and resident of Indiana upon whom service of notices or orders may be made, and upon whom process issued by or under the authority of any court having jurisdiction of the subject matter may be served in any proceeding at law or equity brought against such the   1 carrier.

(b) Service of notices or orders in proceedings under this chapter may be made upon the carrier by personal service upon it, or upon the citizen so designated by it, or by registered mail addressed to it at the last address shown by the records of the department.

(c) In default of that designation, in case of vacancy, or if for any other reason personal service cannot be had upon the carrier, service of the notice or order may be made by serving two (2) copies upon the department.  When service is had upon the department as provided in this subsection, the department shall promptly mail one (1) copy of the notice or order served upon him to the carrier by registered mail at the last address shown by the records of the department, and the date of mailing shall be considered as the time when notice is served.

(d) When notice is given by mail as provided in this section, the date of mailing shall be considered the time when notice is served.