School buses manufactured or converted after January 1, 1978, shall bear a certification label from the final stage manufacturer stating that the completed school bus conforms to applicable FMVSS in effect at the time of manufacture. Persons or entities may not alter a previously certified school bus in a way that does not conform to applicable FMVSS in effect at the time of manufacture.
67 Pa. Code § 171.45
The provisions of this §171.45 amended under the Vehicle Code, 75 Pa.C.S. §§ 4103, 4551-4553 and 6103.