Any officer arresting, or participating or assisting in the arrest of, a person charged with violating the motor vehicle or traffic laws of the city, provided the offense is punishable as a misdemeanor, such officer being on duty exclusively or for the main purpose of enforcing the laws, is incompetent to testify as a witness in any prosecution against the arrested person if the officer at the time of the arrest was not wearing a distinctive uniform in accordance with § R.C. 4549.15.
(ORC § 4549.16)