DOT Helmet Safety Standards - What Constitutes "Minimum Safety Requirements"?

September 05, 2020 4 min read



Motorcycle helmets have saved an estimated 1,885 and 1,872 lives in 2016 and 2017, respectively from serious injury according to the U.S. Department of Transportation 1. By constructing a helmet that effectively manages energy from impacts, motorcyclists are able to significantly reduce brain trauma during accidents and are more likely to survive crashes. Regardless of which helmet rating standard you choose, the use of a helmet with a legitimate certification will reduce your chances of serious injury.

Motorcycle Helmet Laws in the United StatesThe FMVSS 218 Standard consists of multiple tests to ensure pre-established safety criterion have been met prior to helmet issuance to the consumer 3. These tests include:Currently, 47 states have some form of law mandating the use of helmets. Of these 47, 18 states and the District of Columbia have universal helmet laws. Illinois, Iowa, and New Hampshire are the only three states that do not have any helmet requirements in America. Any motorcycle rider that must abide by the state helmet law, must ensure that they are wearing a helmet that is the Department of Transportation (DOT) approved which follows the FMVSS 218 Standard. The DOT certification is the bare minimum safety rating a helmet must achieve before it is considered legal by state law.


  • Impact Attenuation
  • Outer Shell Penetration
  • Chin Strap Retention
  • Peripheral Vision
  • Projections


Environmental Conditioning


Prior to conducting these tests, all helmets are subjected to environmental conditioning where they are forced to endure ambient temperatures (61-79ᵒF and a relative humidity of 30-70%), low temperatures (5-23ᵒF), high temperatures (113-131ᵒF), and water immersion (continuous water spray with ambient water temperature) in order to simulate the conditions a rider is reasonably expected to face during his or her ride. This conditioning period lasts at least four hours and no longer than 24 hours.


DOT Impact Attenuation Drop Test

Impact Attenuation Test


During the Impact Attenuation Test, a given helmet is dropped a total of 32 times for each model and size. Four locations on the helmet are tested with two successive impacts on each location. Two are conducted on a flat steel anvil and two are conducted onto a hemispherical anvil. These anvils simulate different surface areas a rider may encounter during a fall. The impact speed of the helmet must reach 19 - 20.3ft/s on the flat anvil and 16.4 - 17.7ft/s on the hemispherical anvil. A helmet passes this test as long as the peak acceleration does not exceed 400G.





Penetration Test


The Penetration Test focuses on the protection a helmet’s outer shell provides against a sharp object. In this test, a striker weighing 6lbs 8 – 12oz falls from a height of 118.1in ± 0.6in. Two penetration blows are conducted during the attenuation test. As long as the striker does not penetrate the helmet’s outer shell and does not touch the head form on which the helmet is mounted, the helmet passes the test.


DOT Retention System Chin Strap TestRetention System Test



Chin straps are also tested for their retention under a given load. With the helmet securely mounted, the chin straps are placed under a preliminary test load of 50lbs for 30 seconds. An additional test load of 250lbs is then applied for 120 seconds. At the conclusion of the test, the change in position of the adjustable portion of the retention system is measured.






Peripheral Vision Test


Helmet safety also includes the amount of peripheral vision a helmet provides. Because full face and modular helmet visors are specifically designed to provide a rider with an unrestricted view of his or her environment, only full face helmet visors are considered for this test. Visors that are attached to any other helmet style are not tested since DOT considers these visors a convenience. The peripheral vision test simply requires the visor to provide 105ᵒ of vision from either side of the center of the visor providing the rider with a total of 210ᵒ of peripheral vision.


Projections Test


The final requirement a helmet needs to meet is for the helmet to have a minimum amount of rigid projections. This requirement reduces the amount of injuries a rider may sustain if pieces of the helmet become dislodged. The standard requires that no helmets have any rigid projections inside of the helmet shell. The outside is limited to operations of essential accessories and shall not protrude more than 0.2in from the outer shell.




Once the helmet meets these requirements, it meets the FMVSS 218 Standard and will be deemed DOT compliant. Manufacturers are given the liberty to conduct these tests inside their own facilities prior to distributing them to the consumer. The DOT periodically conducts quality control by buying helmets from the manufacturer and conducting their own tests. If they do not meet the FMVSS 218 Standard, they are “pulled from the shelves” and a recall is issued.

All helmets at 421 Moto Gear are DOT certified! Click here to see our collection!




[1] U.S. Department of Transportation, National Highway Traffic Safety Administration, National Center for Statistics and Analysis, Traffic Safety Facts,Crash, available at

[2] U.S. Department of Transportation. Federal Motor Vehicle Safety Standard No. 218. 49 CFR 571.218.Department of Transportation, National Highway Traffic Safety Administration, Washington, DC, US, 1974.

[3] NHTSA, Standard No. 218; Motorcycle Helmets, Code of Federal Regulations Title 49 Part 571.218, Retrieved from