VEH § 680

(a) A “youth bus” is any bus, other than a schoolbus, designed for and when actually carrying not more than 16 persons and the driver, used to transport children at or below the 12th-grade level directly from a public or private school to an organized nonschool-related youth activity within 25 miles of the school or directly from a location which provides the organized nonschool-related youth activity to a public or private school within 25 miles of that location.

(b) In addition to the destinations specified in subdivision (a), a youth bus may also be used to transport children at or below the 12th-grade level to or from their place of residence if the driver has met the requirements of Section 12523 and received additional instruction and training approved by the Department of the California Highway Patrol.