Tennessee Code Title 55. Motor and Other Vehicles § 55-52-106

(a) Except as provided in subsection (b), any adult person violating any requirements set forth in § 55-52-105, commits a violation and shall be assessed a civil penalty of two dollars ($2.00) and court costs.

(b) Upon commission of the first offense within a twelve-month period under § 55-52-105(3), it shall be a defense that the accused has since the date of the violation purchased or provided a protective bicycle helmet or a restraining seat, and uses and intends to use or causes to be used or intends to cause to be used the same as the law requires.

(c) In no event shall failure to wear a protective bicycle helmet or to secure a passenger to a restraining seat be admissible as evidence in a trial of any civil action.

(d) A law enforcement officer observing any violation of this part shall issue a warning to the violator for the first offense and a citation to the violator for the second or subsequent offense, but shall not arrest or take into custody any person solely for a violation of this part.