Me. Rev. Stat. tit. 12, § 13159

Notwithstanding section 13155 and section 13157‑A, subsection 16, paragraph A, subsection 17 and subsection 25, ATVs used exclusively for scheduled racing meets and operated solely on predefined race courses are exempt from the provisions of this chapter concerning registration, mufflers, snorkel kits and lights during the time of operation at these meets and at all prerace practices at the location of the meets.