Texas Transportation Code - TRANSP § 547.204. Vehicle Equipment Testing:  Federal Standards

(a) For a vehicle or item of vehicle equipment subject to a motor vehicle safety standard of the United States, the department may, on or after the first sale of the vehicle or item of vehicle equipment:

(b) The department may not require certification or approval of an item of vehicle equipment subject to a motor vehicle safety standard of the United States.

(c) The department may not require a manufacturer of a vehicle or of an item of vehicle equipment subject to a motor vehicle safety standard of the United States to use an outside laboratory or a specified laboratory.