(a) This subpart applies to for-hire motor carriers transporting passengers in interstate or foreign commerce.

(b) Exception. The rules in this subpart do not apply to—

(1) A motor vehicle transporting only school children and teachers to or from school;

(2) A motor vehicle providing taxicab service and having a seating capacity of less than 7 passengers and not operated on a regular route or between specified points;

(3) A motor vehicle carrying less than 16 individuals in a single daily round trip to commute to and from work; and

(4) A motor vehicle operated by a motor carrier under contract providing transportation of preprimary, primary, and secondary students for extracurricular trips organized, sponsored, and paid by a school district.