FMSCA Regulation 372.103
372.103 Motor vehicles employed solely in transporting school children and teachers to or from school.
The exemption set forth in 49 U.S.C.13506(a)(1) shall not be construed as being inapplicable to motor vehicles being used at the time of operation in the transportation of school children and teachers to or from school, even though such motor vehicles are employed at other times in transportation beyond the scope of the exemption.