FMVSS 202a: Head Restraints explained.

What FMVSS 202a says it is for

The eCFR heads this section "Standard No. 202a; Head restraints; Mandatory applicability begins on September 1, 2009." 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 571.202a as current through October 29, 2026.

This standard specifies requirements for head restraints to reduce the frequency and severity of neck injury in rear-end and other collisions.

What it applies to

The application section of the standard says:

This standard applies to passenger cars, and to multipurpose passenger vehicles, trucks and buses with a GVWR of 4,536 kg or less, manufactured on or after September 1, 2009. However, the standard's requirements for rear head restraints do not apply to vehicles manufactured before September 1, 2010, and, for vehicles manufactured between September 1, 2010 and August 31, 2011, the requirements for rear head restraints apply only to the extent provided in S7. Until September 1, 2009, manufacturers may comply with the standard in this § 571.202a, with the standard in § 571.202, or with the European regulations referenced in S4.3(a) of § 571.202. For vehicles manufactured on or after September 1, 2009 and before September 1, 2010, manufacturers may comply with the standard in § 571.202 or with the European regulations referenced in S4.3(a) of § 571.202, instead of the standard in this § 571.202a, only to the extent consistent with the phase-in specified in this § 571.202a.

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 571.202a has these top-level sections:

• S1: Purpose and scope
• S2: Application
• S3: Definitions
• S4: Requirements
• S5: Procedures
• S6: Vehicles manufactured on or after September 1, 2009, and before September 1, 2010 (Phase-in of § 571.202a)
• S7: Vehicles manufactured on or after September 1, 2010, and before September 1, 2011 (Phase-in of rear seat requirements of § 571.202a)

In all, the text has 50 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 13 of 13):

• S4.1 Performance levels
• S4.2 Dimensional and static performance
• S4.3 Dynamic performance and width
• S4.4 Folding or retracting rear head restraints non-use positions
• S4.5 Removability of head restraints
• S4.6 Compliance option selection
• S4.7 Information in owner's manual
• S5.2 Dimensional and static performance procedures
• S5.3 Procedures for dynamic performance
• S6.1 Phase-in percentage
• S6.2 Vehicles produced by more than one manufacturer
• S7.1 Phase-in percentage
• S7.2 Vehicles produced by more than one manufacturer

Key requirements, quoted from the text

These are excerpts from the requirements sections of 571.202a, 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. Except as provided in S4.4, S4.2.1(a)(2) and S4.2.1(b)(2) of this section, each vehicle must comply with S4.1 of this section with the seat adjusted as intended for occupant use. Whenever a range of measurements is specified, the head restraint must meet the requirement at any position of adjustment within the specified range.

S4.1 Performance levels. In each vehicle other than a school bus, a head restraint that conforms to either S4.2 or S4.3 of this section must be provided at each front outboard designated seating position. In each equipped with rear outboard head restraints, the rear head restraint must conform to either S4.2 or S4.3 of this section. In each school bus, a head restraint that conforms to either S4.2 or S4.3 of this section must be provided for the driver's seating position. At each designated seating position incapable of seating a 50th percentile male Hybrid III test dummy specified in 49 CFR part 572, subpart E, the applicable head restraint must conform to S4.2 of this section.

S4.2 Dimensional and static performance. Each head restraint located in the front outboard designated seating position and each head restraint located in the rear outboard designated seating position must conform to paragraphs S4.2.1 through S4.2.7 of this section. Compliance is determined for the height requirements of S4.2.1 and the backset requirements of S4.2.3 of this section by taking the arithmetic average of three measurements.

S4.2.1 Minimum height. (a) Front outboard designated seating positions. (1) Except as provided in S4.2.1(a)(2) of this section, when measured in accordance with S5.2.1(a)(1) of this section, the top of a head restraint located in a front outboard designated seating position must have a height not less than 800 mm in at least one position of adjustment. (2) Exception. The requirements of S4.2.1(a)(1) do not apply if the interior surface of the vehicle at the roofline physically prevents a head restraint, located in the front outboard designated seating position, from attaining the required height. [...]

S4.2.2 Width. When measured in accordance with S5.2.2 of this section, 65 ±3 mm below the top of the head restraint, the lateral width of a head restraint must be not less than 170 mm, except the lateral width of the head restraint for front outboard designated seating positions in a vehicle with a front center designated seating position, must be not less than 254 mm.

S4.2.3 Front Outboard Designated Seating Position Backset. When measured in accordance with S5.2.3 of this section, the backset must not be more than 55 mm, when the seat is adjusted in accordance with S5.1. For adjustable restraints, the requirements of this section must be met with the top of the head restraint in any height position of adjustment between 750 mm and 800 mm, inclusive. If the top of the head restraint, in its lowest position of adjustment, is above 800 mm, the requirements of this section must be met at that position. If the head restraint position is independent of the seat back inclination position, the head restraint must not be adjusted such that backset is more than 55 mm when the seat back inclination is positioned closer to vertical than the position specified in S5.1.

S5 Procedures. Demonstrate compliance with S4.2 through S4.4 of this section as follows. The positions of seat adjustment specified in S5 and S5.1 are conditions to be met concurrently and are not a sequential list of adjustments. Any adjustable lumbar support is adjusted to its most posterior nominal design position. If the seat cushion adjusts independently of the seat back, position the seat cushion such that the highest H-point position is achieved with respect to the seat back, as measured by SAE Standard J826 JUL95 (incorporated by reference, see § 571.5) manikin, with leg length specified in S10.4.2.1 of § 571.208 of this Part. If the specified position of the H-point can be achieved with a range of seat cushion inclination angles, adjust the seat inclination such that the most forward part of the seat cushion is at its lowest position with respect to the most rearward part. All tests specified by this standard are conducted with the ambient temperature between 18 degrees C. and 28 degrees C. [...]

S5.1.1 Procedure for determining presence of head restraints in rear outboard seats. Measure the height of the top of a rear seat back or the top of any independently adjustable seat component attached to or adjacent to the rear seat back in its highest position of adjustment using the scale incorporated into the SAE Standard J826 JUL95 (incorporated by reference, see § 571.5) manikin or an equivalent scale, which is positioned laterally within 15 mm of the centerline of the rear seat back or any independently adjustable seat component attached to or adjacent to the rear seat back.

S5.2 Dimensional and static performance procedures. Demonstrate compliance with S4.2 of this section in accordance with S5.2.1 through S5.2.7 of this section. Position the SAE Standard J826 JUL95 (incorporated by reference, see § 571.5) manikin according to the seating procedure found in SAE Standard J826 JUL95.

S5.2.1 Procedure for height measurement. Demonstrate compliance with S4.2.1 of this section in accordance with S5.2.1 (a) and (b) of this section, using the headroom probe scale incorporated into the SAE Standard J826 JUL95 (incorporated by reference, see § 571.5) manikin with the appropriate offset for the H-point position or an equivalent scale, which is positioned laterally within 15 mm of the head restraint centerline. If the head restraint position is independent of the seat back inclination position, compliance is determined at a seat back inclination position closest to the design seat back angle, and each seat back inclination position less than the design seat back angle. [...]

S5.2.2 Procedure for width measurement. Demonstrate compliance with S4.2.2 of this section using calipers to measure the maximum dimension perpendicular to the vehicle vertical longitudinal plane of the intersection of the head restraint with a plane that is normal to the torso reference line of SAE Standard J826 JUL95 (incorporated by reference, see § 571.5) manikin and 65 ±3 mm below the top of the head restraint.

S5.2.3 Procedure for backset measurement. Demonstrate compliance with S4.2.3 of this section using the HRMD positioned laterally within 15 mm of the head restraint centerline. Adjust the front head restraint so that its top is at any height between and inclusive of 750 mm and 800 mm and its backset is in the maximum position other than allowed by S4.4. If the lowest position of adjustment is above 800 mm, adjust the head restraint to that position. If the head restraint position is independent of the seat back inclination position, compliance is determined at each seat back inclination position closest to and less than the design seat back angle.

S6 Vehicles manufactured on or after September 1, 2009, and before September 1, 2010 (Phase-in of § 571.202a). (a) For vehicles manufactured for sale in the United States on or after September 1, 2009, and before September 1, 2010, a percentage of the manufacturer's production, as specified in S6.1, shall meet the requirements specified in this § 571.202a without regard to any option to comply with the standard in § 571.202 or with the European regulations referenced in S4.3(a) of § 571.202. So long as this percentage requirement is met, a vehicle may comply with the standard in this § 571.202a, with the standard in § 571.202, or with the European regulations referenced in S4.3(a) of § 571.202. (b) Notwithstanding S6(a), vehicles that are manufactured in two or more stages or that are altered (within the meaning of 49 CFR 567.7) after having previously been certified in accordance with part 567 of this chapter may comply with the standard in this § 571.202a, with the standard in § 571.202, or with the European regulations referenced in S4.3(a) of § 571.202.

S6.2 Vehicles produced by more than one manufacturer. S6.2.1 For the purpose of calculating average annual production of vehicles for each manufacturer and the number of vehicles manufactured by each manufacturer under S6.1, a vehicle produced by more than one manufacturer shall be attributed to a single manufacturer as follows, subject to S6.2.2. (a) A vehicle that is imported shall be attributed to the importer. (b) A vehicle manufactured in the United States by more than one manufacturer, one of which also markets the vehicle, shall be attributed to the manufacturer that markets the vehicle. [...]

S7 Vehicles manufactured on or after September 1, 2010, and before September 1, 2011 (Phase-in of rear seat requirements of § 571.202a). (a) For vehicles manufactured for sale in the United States on or after September 1, 2010, and before September 1, 2011 a percentage of the manufacturer's production of vehicles equipped with rear outboard head restraints, as specified in S7.1, shall meet the requirements specified in this § 571.202a for rear head restraints. (b) Vehicles that are manufactured in two or more stages or that are altered (within the meaning of 49 CFR 567.7) after having previously been certified in accordance with part 567 of this chapter are not subject to the requirement specified in S7(a).

S7.2 Vehicles produced by more than one manufacturer. S7.2.1 For the purpose of calculating average annual production of vehicles for each manufacturer and the number of vehicles manufactured by each manufacturer under S7.1, a vehicle produced by more than one manufacturer shall be attributed to a single manufacturer as follows, subject to S7.2.2. S7.2.2 A vehicle produced by more than one manufacturer shall be attributed to any one of the vehicle's manufacturers specified by an express written contract, reported to the National Highway Traffic Safety Administration under 49 CFR part 585, between the manufacturer so specified and the manufacturer to which the vehicle would otherwise be attributed under S7.2.1.

Defined terms

The standard defines 4 terms in its definitions section; the first 4 are quoted here from the eCFR.

• Backset means the minimum horizontal distance between the rear of a representation of the head of a seated 50th percentile male occupant and the head restraint, as measured by the head restraint measurement device.
• Head restraint means a device that limits rearward displacement of a seated occupant's head relative to the occupant's torso.
• Head restraint measurement device (HRMD) means the three dimensional SAE Standard J826 JUL95 (incorporated by reference, see § 571.5) manikin with a head form attached, representing the head position of a seated 50th percentile male, with sliding scale at the back of the head for the purpose of measuring backset. The head form is designed by and available from the ICBC, 151 West Esplanade, North Vancouver, BC V7M 3H9, Canada (www.icbc.com).
• Top of the head restraint means the point on the head restraint with the greatest height.

Limits of this page

This page quotes the text of 49 CFR 571.202a 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 571.202a, Standard No. 202a; Head restraints; Mandatory applicability begins on September 1, 2009. (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)