FMVSS 225: Child Restraint Anchorage Systems explained.

What FMVSS 225 says it is for

The eCFR heads this section "Standard No. 225; Child restraint anchorage systems." 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 571.225 as current through October 29, 2026.

This standard establishes requirements for child restraint anchorage systems to ensure their proper location and strength for the effective securing of child restraints, to reduce the likelihood of the anchorage systems' failure, and to increase the likelihood that child restraints are properly secured and thus more fully achieve their potential effectiveness in motor vehicles.

What it applies to

The application section of the standard says:

This standard applies to passenger cars; to trucks and multipurpose passenger vehicles with a gross vehicle weight rating (GVWR) of 3,855 kilograms (8,500 pounds) or less; and to buses (including school buses) with a GVWR of 4,536 kg (10,000 lb) or less. This standard does not apply to walk-in van-type vehicles, vehicles manufactured to be sold exclusively to the U.S. Postal Service, shuttle buses, and funeral coaches.

Applicability is decided by the text of the standard as written, including any exclusions it lists, and by the date-specific rules in it. This page does not decide whether a particular vehicle or item is covered.

How the standard is organized

The eCFR text of 571.225 has these top-level sections:

• S1: Purpose and scope
• S2: Application
• S3: Definitions
• S4: General vehicle requirements
• S5: General exceptions
• S6: Requirements for tether anchorages
• S7: Test conditions for testing tether anchorages
• S8: Test procedures
• S9: Requirements for the lower anchorages of the child restraint anchorage system
• S10: Test conditions for testing the lower anchorages
• S11: Test procedures
• S12: Written instructions
• S13: Phase-in schedule

In all, the text has 57 numbered headings. Use the finder above to search them; for example, a search for "test" lists the headings that mention tests.

Second-level headings at a glance

These are the numbered sub-sections one level below the top, in order (first 12 of 19):

• S4.1 Each tether anchorage and each child restraint anchorage system installed, either…
• S4.2 Vehicles shall be equipped as specified in paragraphs S4.2(a) through (c), except as…
• S4.3 Movable seats
• S5.1 Vehicles manufactured before September 1, 2031
• S5.2 Vehicles manufactured on or after September 1, 2031
• S6.1 Configuration of the tether anchorage
• S6.2 Location of the tether anchorage
• S6.3 Strength requirements for tether anchorages
• S6.4 Marking and conspicuity requirements for tether anchorages
• S8.1 Apply the force specified in S6.3 as follows
• S9.1 Configuration of the lower anchorages
• S9.2 Location of the lower anchorages

Key requirements, quoted from the text

These are excerpts from the requirements sections of 571.225, 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.

S4.1. Each tether anchorage and each child restraint anchorage system installed, either voluntarily or pursuant to this standard, in any new vehicle manufactured on or after September 1, 1999, shall comply with the configuration, location, marking and strength requirements of this standard. The vehicle shall be delivered with written information, in English, on how to appropriately use those anchorages and systems.

S4.2. Vehicles shall be equipped as specified in paragraphs S4.2(a) through (c), except as provided in S5 of this standard. (a) Each vehicle with three or more forward-facing rear designated seating positions shall be equipped as specified in S4.2(a)(1) and (2). (1) Each vehicle shall be equipped with a child restraint anchorage system conforming to the requirements of S6 and S9 of this standard at not fewer than two forward-facing rear designated seating positions. At least one of the child restraint anchorage systems shall be installed at a forward-facing seating position in the second row in each vehicle that has three or more rows, if such a forward-facing seating position is available in that row. (2) Each vehicle shall be equipped with a tether anchorage conforming to the requirements of S6 of this standard at a third forward-facing rear [...]

S4.3 Movable seats. (a) A vehicle that is equipped with a forward-facing rear designated seating position that can be moved such that it is capable of being used at either an outboard or non-outboard forward-facing designated seating position shall be considered as having a forward-facing non-outboard designated seating position. Such a movable seat must be equipped with a tether anchorage that meets the requirements of S6 of this standard or a child restraint anchorage system that meets the requirements of S6 and S9 of this standard, if the vehicle does not have another forward-facing non-outboard designated seating position that is so equipped. (b) Tether and lower anchorages shall be available for use at all times, except when the seating position for which it is installed is not available for use because the vehicle seat has been removed or converted to [...]

S6 Requirements for tether anchorages. Vehicles subject to Standard No. 225 (this section) shall meet the tether anchorage requirements specified in S6.1, S6.2, and S6.4 according to the phase-in schedule specified in S13 of this standard.

S6.1.1 Each tether anchorage shall. (a) Permit the attachment of a tether hook of a child restraint system meeting the configuration and geometry specified in figure 11 of Standard No. 213 (figure 11 to § 571.213); (b) Be accessible without the need for any tools other than a screwdriver or coin; (c) Once accessed, be ready for use without the need for any tools; and (d) Be sealed to prevent the entry of exhaust fumes into the passenger compartment.

S6.1.2 Each tether anchorage shall. (a) Consist of a rigid bar of any cross-section shape that permits the attachment of a tether hook (of a child restraint system) meeting the configuration and geometry specified in figure 11 of Standard No. 213 (figure 11 to § 571.213), except in buses with a GVWR less than or equal to 10,000 pounds and vehicles that use a routing device per S6.2.1.2; (b) Be accessible without the need for any tools and without folding the seat back (other than the head restraint) or removing carpet or other vehicle components (other than cargo covers) to access the anchorages. Individual tether anchorages may be covered with a cap, flap, or cover, provided that any cap, flap, or, cover is specifically designed to be opened, moved aside, or to otherwise give unobstructed access to the anchorage and is labeled with the symbol shown in figure 25 to this [...]

S9 Requirements for the lower anchorages of the child restraint anchorage system. Vehicles subject to Standard No. 225 (this section) shall meet the lower anchorage requirements specified in S9.2 and S9.5 according to the phase-in schedule specified in S13 of this standard.

S9.1.1 The lower anchorages shall consist of two bars that. (a) Are 6 mm ±.1 mm in diameter; (b) Are straight, horizontal and transverse; (c) As shown in Figure 21, are: (i) Not less than 25 mm in length, and (ii) Are not more than 60 mm in length between the anchor bar supports or other structural members of the vehicle that restrict lateral movement of the components of a child restraint that are designed to attach to the bars, measured in a vertical plane 7 mm rearward of the vertical plane that is tangent of the rearward face of the anchor bar. (d) The bars must not be capable of being stowable or foldable. (e) [Reserved] (f) Are part of the vehicle, such that they can only be removed by use of a tool, such as a screwdriver or wrench; and (g) Are rigidly attached to the vehicle such that they will not deform more than 5 mm when subjected to a 100 N force in any direction.

Defined terms

The standard defines 12 terms in its definitions section; the first 10 are quoted here from the eCFR.

• Child restraint anchorage means any vehicle component, other than Type I or Type II seat belts, that is involved in transferring loads generated by a child restraint system to the vehicle structure.
• Child restraint anchorage system means a vehicle system that is designed for attaching a child restraint system to a vehicle at a particular designated seating position, consisting of:
• Child restraint fixture (CRF) means the fixture depicted in Figures 1 and 2 of this standard that simulates the dimensions of a child restraint system, and that is used to determine the space required by the child restraint system and the location and accessibility of the lower anchorages.
• Funeral coach means a vehicle that contains only a front row of occupant seats, is designed exclusively for transporting a body and casket and that is equipped with features to secure a casket in place during operation of the vehicle.
• Rear designated seating position means any designated seating position (as that term is defined at § 571.3) that is rearward of the front seats(s).
• Seat bight means the area close to and including the intersection of the surfaces of the vehicle seat cushion and the seat back.
• SFAD 1 means Static Force Application Device 1 shown in Figures 12 to 16 of this standard.
• SFAD 2 means Static Force Application Device 2 shown in Figures 17 and 18 of this standard.
• Shuttle bus means a bus with only one row of forward-facing seating positions rearward of the driver's seat or, for a vehicle without manually operated controls, means a bus with only one row of forward-facing seating positions rearward of all front row passenger seats.
• Tether anchorage means a user-ready, permanently installed vehicle system that transfers loads from a tether strap through the tether hook to the vehicle structure and that accepts a tether hook.

Limits of this page

This page quotes the text of 49 CFR 571.225 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 571.225, Standard No. 225; Child restraint anchorage systems. (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)