FMVSS 220: School Bus Rollover Protection explained.

What FMVSS 220 says it is for

The eCFR heads this section "Standard No. 220; School bus rollover protection." Under 49 CFR part 571, the Federal Motor Vehicle Safety Standards are the numbered standards that set safety performance requirements for motor vehicles and equipment. The text below is quoted from 571.220 as current through October 29, 2026.

This standard establishes performance requirements for school bus rollover protection.

The purpose of this standard is to reduce the number of deaths and the severity of injuries that result from failure of the school bus body structure to withstand forces encountered in rollover crashes.

How the standard is organized

The eCFR text of 571.220 has these top-level sections:

• S1: Scope
• S2: Purpose
• S3: Applicability
• S4: Requirements
• S5: Test procedures
• S6: Test conditions

In all, the text has 9 numbered headings. Use the finder above to search them; for example, a search for "test" lists the headings that mention tests.

Key requirements, quoted from the text

These are excerpts from the requirements sections of 571.220, in the order the standard presents them. Long paragraphs are shortened where marked with [...]; the eCFR has the complete text, tables and figures, which this page omits.

S4 Requirements. When a force in Newtons equal to 1 1/2 times the unloaded vehicle weight in kilograms multiplied by 9.8 m/sec 2 is applied to the roof of the vehicle's body structure through a force application plate as specified in S5, Test procedures— (a) The downward vertical movement at any point on the application plate shall not exceed 130 mm and (b) Each emergency exit of the vehicle provided in accordance with Standard No. 217 (§ 571.217) shall be capable of opening as specified in that standard during the full application of the force and after release of the force, except that an emergency exit located in the roof of the vehicle is not required to be capable of being opened during the application of the force. A particular vehicle (i.e., test specimen) need not meet the emergency exit opening requirement after release of force if it is subjected to the emergency exit opening requirements during the full application of the force.

S5 Test procedures. Each vehicle shall be capable of meeting the requirements of S4. when tested in accordance with the procedures set forth below. S5.1 With any non-rigid chassis-to-body mounts replaced with equivalent rigid mounts, place the vehicle on a rigid horizontal surface so that the vehicle is entirely supported by means of the vehicle frame. If the vehicle is constructed without a frame, place the vehicle on its body sills. Remove any components which extend upward from the vehicle roof. S5.2 Use a flat, rigid, rectangular force application plate that is measured with respect to the vehicle roof longitudinal and lateral centerlines, (a) In the case of a vehicle with a GVWR of more than 4,536 kg, 305 mm shorter than the vehicle roof and 914 mm wide; and (b) In the case of a vehicle with a GVWR of 4,536 kg or less, 127 mm longer and 127 mm wider than the vehicle roof. For purposes of these measurements, the vehicle roof is that structure, seen in the top projected view, that coincides with the passenger and driver compartment of the vehicle. [...]

S5.7 To test the capability of the vehicle's emergency exits to open in accordance with S4.(b)—. (a) In the case of testing under the full application of force, open the emergency exits as specified in S4.(b) while maintaining the force applied in accordance with S5.4 and S5.5; and (b) In the case of testing after the release of all force, release all downward force applied to the force application plate and open the emergency exits as specified in S4.(b).

S6 Test conditions. The following conditions apply to the requirements specified in S4.

S6.1 Temperature. The ambient temperature is any level between 0 °C and 32 °C.

S6.2 Windows and doors. Vehicle windows, doors, and emergency exits are in the fully-closed position, and latched but not locked.

Limits of this page

This page quotes the text of 49 CFR 571.220 as published in the eCFR, current through October 29, 2026. It omits tables, figures, cross-referenced test procedures in other parts, and the preambles and rulemaking history that explain the rule. It does not tell you whether a given vehicle, part or product complies, how to run a test, or what a manufacturer must certify. Compliance questions go to the manufacturer's engineers, qualified counsel or NHTSA. The eCFR is an editorial compilation, not the official legal edition of the Federal Register.

Sources

Sources opened and read November 2, 2026.

• eCFR: 49 CFR 571.220, Standard No. 220; School bus rollover protection. (current through October 29, 2026) (read November 2, 2026)
• eCFR: 49 CFR part 571, Federal Motor Vehicle Safety Standards (current through October 29, 2026) (read November 2, 2026)