In the US there are 2 main safety standards for helmets worn while operating motor vehicles: DOT Certified (Department of Transportation) standards are federally mandated, and Snell M2015 rated.
Snell approved helmets are often required for racing or track events due to increased impact protection, while DOT compliance is required for all helmets used on public roadways in the US.
The National Highways Traffic Safety Administration (NHTSA) specifies standards available to all helmet manufacturers who will be selling helmets within the US market. Helmet manufacturers will design and produce helmets that meet or exceed these predetermined standards. Testing is performed annually only for a small number of randomly selected models, but some manufacturers may choose have their helmets tested by a third party on an annual basis.
All automotive helmets in the US are required to meet these standards
The Department of Transportation has strict requirements regarding impact testing, head retention, field of vision, and resistance to penetration. In addition, it has one of the more rigorous impact testing. A third party randomly tests a select number of helmets every year. Similar to random drug testing in professional sports, testing for DOT standards are done at random.
DOT Helmet Testing
What does it involve?
- Multiple impact attenuation tests include dropping the helmet with from a fixed height onto flat and spherical anvils
- Tested for penetration resistance with a pointed striker at the shell
- Face shield penetration resistance testing
- Field of vision measurements of no less than 105°
- 300 pounds applied to retention system (chin strap) for 120 seconds
DOT vs. ECE
Economic Commission for Europe (ECE) acts similarly to the DOT in the US used by more than 50 countries in Europe, and any helmet with this certification must meet the current ECE 22.05 standard. Available helmets that meet the ECE standards are always independently tested and evaluated before being labeled and marketed to consumers.
ECE testing varies from DOT standards in some areas. Additional testing is performed to ensure abrasion resistance to minimize twisting of the neck when the helmet is worn, and additional tests to ensure rigidity and rotational force that may be caused by any protruding parts such as snaps, rivets, brackets etc.
One of the biggest differences that sets ECE testing apart from DOT is the tolerance for peak acceleration energy, or the amount of shock transmitted to the wearer. While DOT compliance allows up to 400 G forces (G), ECE requires no more than 275G. This essentially means a softer impact.
The Snell Memorial Foundation is a non-profit dedicated to improving helmet safety after the death of auto race Pete “William” Snell.
Helmet manufacturers submit helmets for testing prior to labeling individual helmet models as Snell rated. There are several Snell standards for various motorsports, but the two most common and current ratings are SA2015 for automotive sports, and M2015 for motorcycling. Some key differences between Snell SA and Snell M rated helmets are that SA helmets go through flammability testing, use fire retardant materials, and SA helmets will have a slightly narrower field of vision compared to motorcycle specific M rated helmets.
Though there are different testing methods for each standard, Snell certification involves each model of helmet to be tested and approved before helmets can be sold as Snell certified. Snell M2010 and M2015 rated helmets must pass impact testing with a peak acceleration by shell size. Smaller shells have a tolerance of 275G, and larger models up to 243G.
Which is safest?
All 3 standards are available and prevalent in the US from many manufacturers. DOT certified helmets will be the most commonly available and are often the most affordable ranging anywhere from $40-$300 (or more) depending on the features and branding. It is very common to find more expensive models with both DOT and ECE certifications from larger brands, though if you are riding in the US and prefer a lightweight helmet, DOT certified is a great choice. Snell and ECE helmets will come with a higher price tag, but better all around protection.