FMVSS 218: Motorcycle Helmets explained.

What FMVSS 218 says it is for

The eCFR heads this section "Standard No. 218; Motorcycle helmets." 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 571.218 as current through October 29, 2026.

This standard establishes minimum performance requirements for helmets designed for use by motorcyclists and other motor vehicle users.

The purpose of this standard is to reduce deaths and injuries to motorcyclists and other motor vehicle users resulting from head impacts.

What it applies to

The application section of the standard says:

This standard applies to all helmets designed for use by motorcyclists and other motor vehicle users.

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 571.218 has these top-level sections:

• S1: Scope
• S2: Purpose
• S3: Application
• S4: Definitions
• S5: Requirements
• S6: Preliminary test procedures
• S7: Test conditions

In all, the text has 58 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 14):

• S5.1 Impact attenuation
• S5.2 Penetration
• S5.3 Retention system
• S5.4 Configuration
• S5.5 Projections
• S5.6 Labeling
• S5.7 Helmet positioning index
• S6.1 Selection of appropriate headform
• S6.2 Reference marking
• S6.3 Helmet positioning
• S6.4 Conditioning
• S7.1 Impact attenuation test

Key requirements, quoted from the text

These are excerpts from the requirements sections of 571.218, 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.

S5 Requirements. Each helmet shall meet the requirements of S5.1, S5.2, and S5.3 when subjected to any conditioning procedure specified in S6.4, and tested in accordance with S7.1, S7.2, and S7.3.

S5.1 Impact attenuation. When an impact attenuation test is conducted in accordance with S7.1, all of the following requirements shall be met: (a) Peak accelerations shall not exceed 400g; (b) Accelerations in excess of 200g shall not exceed a cumulative duration of 2.0 milliseconds; and (c) Accelerations in excess of 150g shall not exceed a cumulative duration of 4.0 milliseconds.

S5.2 Penetration. When a penetration test is conducted in accordance with S7.2, the striker shall not contact the surface of the test headform.

Defined terms

The standard defines 9 terms in its definitions section; the first 9 are quoted here from the eCFR.

• Basic plane means a plane through the centers of the right and left external ear openings and the lower edge of the eye sockets (Figure 1) of a reference headform (Figure 2) or test headform.
• Discrete size means a numerical value that corresponds to the diameter of an equivalent circle representing the helmet interior in inches (±0.25 inch) or to the circumference of the equivalent circle in centimeters (±0.64 centimeters).
• Helmet positioning index means the distance in inches, as specified by the manufacturer, from the lowest point of the brow opening at the lateral midpoint of the helmet to the basic plane of a reference headform, when the helmet is firmly and properly positioned on the reference headform.
• Impact site means the point on the helmet where the helmet shell first contacts the test anvil during the impact attenuation test.
• Midsagittal plane means a longitudinal plane through the apex of a reference headform or test headform that is perpendicular to the basic plane (Figure 3).
• Reference headform means a measuring device contoured to the dimensions of one of the three headforms described in Table 2 and Figures 5 through 8 with surface markings indicating the locations of the basic, mid-sagittal, and reference planes, and the centers of the external ear openings.
• Reference plane means a plane above and parallel to the basic plane on a reference headform or test headform (Figure 2) at the distance indicated in Table 2.
• Retention system means the complete assembly by which the helmet is retained in position on the head during use.
• Test headform means a test device contoured to the dimensions of one of the three headforms described in Table 2 and Figures 5 through 8 with surface markings indicating the locations of the basic, mid-sagittal, and reference planes.

Limits of this page

This page quotes the text of 49 CFR 571.218 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 571.218, Standard No. 218; Motorcycle helmets. (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)