20 U.S. Code § 1714 - Transportation of students
(a) Limitation to school closest or next closest to place of residence
No court, department, or agency of the United States shall, pursuant to section 1713 of this title, order the implementation of a plan that would require the transportation of any student to a school other than the school closest or next closest to his place of residence which provides the appropriate grade level and type of education for such student.
(b) Health risks; impingement on educational process
No court, department, or agency of the United States shall require directly or indirectly the transportation of any student if such transportation poses a risk to the health of such student or constitutes a significant impingement on the educational process with respect to such student.
(c) School population changes resulting from population changes
When a court of competent jurisdiction determines that a school system is desegregated, or that it meets the constitutional requirements, or that it is a unitary system, or that it has no vestiges of a dual system, and thereafter residential shifts in population occur which result in school population changes in any school within such a desegregated school system, no educational agency because of such shifts shall be required by any court, department, or agency of the United States to formulate, or implement any new desegregation plan, or modify or implement any modification of the court approved desegregation plan, which would require transportation of students to compensate wholly or in part for such shifts in school population so occurring.