In 1972 the National Highway Traffic Safety Administration announced that they were going to develop a standard for motorcycle helmets. The Federal Motor Vehicle Safety Standard 218, commonly referred to as the DOT standard, was written using information and methodology that was developed several years earlier. The initial draft was supposed to be revised before its release in 1974, but the changes were never made. Although the DOT standard could use some alterations, it still provides for a safer helmet then one that has not been DOT approved.
There are two key differences between a DOT- and Snell-approved helmet. First, is the testing standards the helmets go through, and second, is the verification of the results.
It's easy to get lost in the scientific jargon when trying to sift through the testing process of both standards. Simplified, DOT and Snell assess each helmet by placing it on a head form that is equipped with sensors. The helmeted head form is then dropped from a specific height onto a steel anvil, and the severity of the impact is recorded.
DOT and Snell test each helmet two times at four different impact zones. DOT drops their helmets from a 6-foot height on the flat anvil and from a 4.5-foot height on the hemispherical anvil. Snell on the other hand, drops the helmets from a 10-foot and 7.5-foot height on both anvils, which simulates a more severe impact.
DOT certification, however, is less regulated. The manufacturer performs their own tests and determines whether their helmets are DOT approved. Even though the manufacturer doesn't have to report their findings, the government does occasionally conduct limited tests or spot checks. Nevertheless, allowing each company to test their own equipment and not make them report their results means that the DOT certification is done by the honor system.
The DOT standards are important because they outline the minimum requirements all motorcycle helmets must meet, which has already saved countless lives. But if you want to make sure your helmet has been tested impartially, then buying a helmet with the Snell sticker on it is a dependable alternative.
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