Texas Transportation Code - TRANSP § 547.005. Offense Relating to Violation of Special-Use Provisions

(a) A person may not use a slow-moving-vehicle emblem on a stationary object or a vehicle other than a slow-moving vehicle.

(b) A person may not operate a motor vehicle bearing the words “school bus” unless the vehicle is used primarily to transport persons to or from school or a school-related activity.  In this subsection, “school” means a privately or publicly supported elementary or secondary school, day-care center, preschool, or institution of higher education and includes a church if the church is engaged in providing formal education.