Motorcycle Helmet Safety Ratings & Testing: DOT, Snell & More

Explaining the key tests and certifications designed to protect riders

All quality protective headgear is tested and classified for its specific purpose. And given the risks of riding and possible head injuries, motorcycle helmet safety ratings and tests are crucial.

Here’s a look at the leading standards and which marks of approval matter most, including an in-depth review of DOT-approved motorcycle helmets and Snell motorcycle helmets.

Motorcycle helmet safety ratings and the law

Most people are aware of motorcycle helmet laws in various US states, which can be:

  • Universal: all motorcycle riders must wear helmets.
  • Partial: helmets are optional if riders meet specific criteria, such as “age, experience, or scope of medical insurance coverage.” 

Sections of these laws (such as Florida Statute §316.211, Equipment for motorcycle and moped riders) also mandate a minimum quality and protection of this headgear. Specifically, helmets must comply “with Federal Motorcycle Vehicle Safety Standard 218.”

After all, slapping on a leather helmet manufactured in 1914 probably won’t do riders much good in an accident. Additionally, private organizations publish standards and issue ratings, and these can provide more protection than government-designed minimums.

Here are some of the most well-known standards:

  • The Federal Motor Vehicle Safety Standard (FMVSS) 218 is issued by the National Highway Traffic Safety Administration (NHTSA), which is part of the US Department of Transportation (DOT). Thus, a “DOT-approved” motorcycle helmet meets this standard—and modern ones have a decal stating “FMVSS No. 218.”
  • The Economic Commission for Europe’s ECE Regulation No.22 (ECE 22) is a similar testing and classification system in (you guessed it) Europe. Interestingly, the ECE falls under the United Nations, not the European Union.
  • The Safety Helmet Assessment and Rating Programme (SHARP) is a British government standard that tests and classifies helmets based on a five-star rating scheme. The impact resistance of SHARP helmets is also color-coded from green (best) to yellow, orange, brown, red, and black (worst).
  • FRHPhe-01 and FRHPhe-02 are issued by the Fédération Internationale de Motocyclisme (FIM), “the global governing/sanctioning body of motorcycle racing." Headgear meeting these standards are known as “FIM motorcycle helmets.”
  • Snell M2020 and SA20202 are published by the Snell Memorial Foundation, a nonprofit “dedicated to research, education, testing and development of helmet safety standards.” M stands for “Motorcycle Application," and SA stands for “Sports Application” (auto racing). Further, the “M2020D is for markets that use DOT,” whereas M2020R applies to other markets. Snell issues helmet standards in a five-year cycle; so, for example, a previous version was the M2015.

Damaged motorcycle helmet

Some standards test face shields, chin bars, and abrasion resistance, while others don’t.

The most relevant motorcycle helmet safety ratings

Legal relevancy is based on geography. A US rider’s headgear must meet FMVSS No. 218 and thus be a “DOT-approved motorcycle helmet.” European riders and authorities are concerned with the ECE 22, of course.

Assessing the quality of various standards is more complex, however. First, helmets with multiple ratings are available worldwide. For example, it’s common to see a helmet complying with DOT and ECE, DOT and Snell, or all three.

Of note, manufacturers test and rate their products to mark them as DOT-approved motorcycle helmets, not the government. Then, the NHTSA tests samples to verify compliance. In contrast, Snell motorcycle helmets are tested by Snell technicians at a Snell facility before achieving the certification. The bottom line: riders should always buy protective headgear from trusted manufacturers who make quality products to ensure a helmet performs as advertised.

Let’s dive deeper into the tests for the two most common ratings in the US.

DOT logo

DOT-approved motorcycle helmet tests

FMVSS No. 218’s purpose is to reduce “deaths and injuries to motorcyclists and other motor vehicle users resulting from head impacts.” It aims to accomplish this goal with three primary tests: 

1. Impact Attenuation Test: Testers drop head forms (dummy heads) wearing helmets onto anvils. Each “is impacted at four sites with two successive impacts;” two on a “flat steel anvil and two upon a hemispherical steel anvil.” Peak accelerations must not exceed 400g, “accelerations in excess of 200 g shall not exceed a cumulative duration of 2.0 milliseconds,” and “accelerations in excess of 150 g shall not exceed a cumulative duration of 4.0 milliseconds.

2. Penetration Test: Testers drop a striker weighing a bit over 6 lbs. from 10’ 10” above a helmeted head form. The helmet fails if there is “contact between the striker and the surface of the test head form at any point above the test line.

3. Retention System Test: Testers ensure the strength and stability of the “helmet retention assembly” by applying a “quasi-static tensile load” to it while holding the head form in place. To pass, no part of the retention assembly can separate, and its adjustable portion can’t move more than 2.5 cm.

In addition, FMVSS No. 218 specifies:

  • Configuration requirements that all helmets “have a protective surface of continuous contour at all points on or above [a] test line” and meet criteria for adequate peripheral vision.

DOT peripheral vision requirements for motorcycle helmets

The peripheral vision requirements in FMVSS No. 218.

  • Helmets must have no “rigid projections inside” the shell or on the outside, except external ones necessary for attachments and protruding no more than 5mm. 
  • Proper, permanent labeling should include the manufacturer, size, month and year of manufacture, safety instructions, and certification information.

Snell logo

Snell motorcycle helmet tests

Snell does more tests of varying protection aspects and uses some different thresholds:

1. Impact Test: It’s a similar protocol to DOT. However, head forms are dropped on more anvil types, and while the precise limits vary, any peak acceleration of approximately 260-300g fails instead of DOT’s 400g

2. Positional Stability (Roll-Off) Test: Testers attach a rope to the helmeted head form placed on a stand and drop a 4 kg weight into a stop at the bottom of the rope. The test is repeated at the front and rear of the helmet, each measure putting “a rotational load” on it. To pass the test, the headgear can shift but “must not roll off the head form.” Here’s a video demonstration:


3. Dynamic Retention Test: This test is roughly equivalent to the DOT’s Retention System Test, except it uses a dynamic Testers load the chin strap on a helmeted head form with “a 23 kg weight for approximately one minute. The retention system is tested by simultaneously removing the 23 kg weight and applying a 38 kg mass in an abrupt guided fall.” To pass, “the helmet may be shifted but must not roll off the head form.” Here it is:


4. Shell Penetration Test: Similar to the DOT penetration test, testers drop a cone-tipped striker of about 6.6 lbs. at 7.45 ± 0.15 meters per second (m/s). Again, “the test striker must not penetrate through the helmet wall.” Here’s what it looks like:

The above tests are just the essential ones. Snell conducts additional assessments for specific helmet types:

  • The Chin Bar Rigidity Test, in which testers drop a weight onto a chin bar, "applies to full face motorcycle, special application racing and kart racing helmets."
  • The Faceshield Penetration Test, also for "full-face motorcycle, special application racing and kart racing helmets," involves shooting the shield with a pellet gun.
  • A Flame Resistance Test and Chin Bar Impact Test, involving a propane flame and a flat anvil, respectively, are for “special application racing helmets.”

Like FMVSS No. 218, Snell M2020 and SA2020 also have labeling, structural, and peripheral vision requirements for all helmets, with the last item specifying upward visual clearance, lateral visual clearance, and downward visual clearance specs.

Snell upward visual clearance test

A diagram of one of the three peripheral vision requirements in Snell’s SA2020. The latest M2020 requirements are similar, but the upward visual clearance shown above must be at least 7°.

So, which safety ratings matter?

Ultimately, all major standards help ensure quality helmets. Snell has better impact specs based on its acceleration thresholds, but DOT-approved motorcycle helmets also offer riders significant protection, as do ECE, FRHPhe, and SHARP.

A final tip: some manufacturers and sellers get around the legal requirement for DOT-approved motorcycle helmets by selling headgear as a “novelty” item. Do not use equipment without this crucial certification if protection is the goal!

Check out the rest of the Hard Head Veterans blog to learn more about helmet safety, including how helmets mitigate TBIs and other wounds and how motorcycle helmets manage head injury risks.