DOT Vs. SNELL: What Is Underneath

We write these articles week in and week out for you, our faithful readers and our dedicated riders, to keep you as informed as we can about issues of safety and your overall health. We have discussed helmets previously, along with head injuries. But this week, we are going to go a little deeper into the world of helmet safety and tell you about the DOT and Snell stamps you see on the back of helmets; these are the two organizations that set helmet safety standards here in the United States.

The background

The Federal Government’s Department of Transportation (DOT) sets minimum standards that all helmets sold for motorcycling must meet. The standard, developed in 1974, is the Federal Motor Vehicle Safety Standard 218, but is commonly known as the DOT standard. It was originally drafted in 1972 and was expected to go through a number of extensive changes, but revisions never happened before its release. Though it is much better to have the DOT standard than not, it is a much forgiving standard than that of the Snell Memorial Foundation.

The Snell Memorial Foundation was founded in 1957 for William “Pete” Snell after he died from massive head trauma he sustained in a race car accident. It is a non-profit organization that is focused on learning more about head injuries and how to prevent them. Snell standards are updated and tested every five years, forcing helmet makers to continually improve their products so that they will be approved by Snell standards. They have standards that apply to motorcycle, bike and automobile racing helmets, along with other protective headgear.

The differences

While both DOT and Snell standards are designed to keep helmet safety levels at top peak and are similar, there are two key differences in their approved helmets. These are the testing procedures that the helmets go through and the way that the test results are verified and reported.


For the sake of this article, we will be as simple as possible in explaining the details. Both standards are lengthy and quite in depth, but here is the general idea: both DOT and Snell test their helmets by putting it on a head form that is designed with sensors attached to measure the severity of impact. Then the head form is dropped from a specified height onto a steel anvil. Measurements are taken right before impact and are measured in terms of how much mechanical energy is generated during the test. The amount of energy is determined by the speed of the head at the moment of impact, along with its weight.

Both testing standards have the helmets dropped in their head forms onto a flat and a hemispherical shaped anvil, but Snell goes a step further and also tests them on an edged anvil. The different types of anvils are meant to recreate different types of impacts.

All helmets are tested two times at four different impact zones. While the DOT has the helmets dropped from 6 ft. on the flat anvil and 4.5 ft. on the hemispherical anvil, Snell drops theirs from 10 ft. and 7.5 ft. on both anvils, making the impact simulation that of a more severe one. Since Snell uses the edged anvil and drops the head forms from a higher height, their standards require that helmets withstand a much larger impact and absorb more force than that of the DOT.

*Verification and Reporting

DOT and Snell both have tests that are ran and procedures that are to be followed, but the DOT testing is done by the helmet makers and is done on the honor system, while the Snell Memorial Foundation test the helmets themselves.

DOT testing is done by the manufacturer. They perform the tests and determine whether or not their helmets are DOT approved. It is not required that the manufacturers report their findings, but the government does occasionally do random tests or unannounced checks. Either way, the DOT standards and approval are very much based on the honesty of the manufacturer: that the tests have been done and been done properly and they are indeed up to DOT standards. Not having to report their findings is one fault of the DOT standards reporting.

Snell approval is determined by the Snell Memorial Foundation. The manufacturer has to submit five helmets: four for testing and one to be saved as a sample. If the helmet sample passes testing, then the helmet manufacturer enters into a contract with Snell. Then, Snell is able to buy helmets from the manufacturer whenever they like and randomly test them on a regular basis to make sure that the quality they passed is what the helmets are maintained at.

The outcome

While the DOT standards have been tremendously useful in setting minimum helmet guidelines, they cannot guarantee that their approved helmets have actually been tested. Along with that, the testing standards are far under that of the Snell standard requirements. Overall, the Snell standard is one that ensures greater impact and force protection and is guaranteed to be tested in proper testing facilities and will be followed up on on a regular basis.

Always remember, helmets withstand one crash. After a crash, whether the shell has been damaged or there is damage to the foam inside, the helmet must be replaced for you, the rider, to be safe.

In order to get full information on both DOT and Snell standards, please check out their websites at and

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