Indiana Code Title 6. Taxation § 6-6-14-7

Sec. 7. (a) The administrator shall issue an alternative fuel decal to an owner of a motor vehicle propelled by alternative fuel who applies for a decal, pays to the administrator the fee, and provides the information that is required by the administrator.

(b) An alternative fuel decal is effective from April 1 of each year through March 31 of the next year. The administrator may extend the expiration date for not more than thirty (30) days. During the month of March, the owner shall display the valid decal through March 31 or the decal issued to the owner for the next twelve (12) months. If the administrator grants an extension of the expiration date, the owner shall continue to display the decal for which the extension was granted.