Tripper service means regularly scheduled mass transportation service which is open to the public, and which is designed or modified to accommodate the needs of school students and personnel, using various fare collections or subsidy systems. Buses used in tripper service must be clearly marked as open to the public and may not carry designations such as school bus or school special. These buses may stop only at a grantee or operator's regular service stop. All routes traveled by tripper buses must be within a grantee's or operator's regular route service as indicated in their published route schedules.
49 CFR § 605.3
Except as otherwise provided, terms defined in the Federal Mass Transit Act of 1964, as amended (49 U.S.C. 1604, 1608) are used in this part as so defined.