Interesting read below.
My sled helmet has a Snell Rating, my road race helmet is Snell SA.
What are the differences between the SA and M standards?
The Snell Memorial Foundation SA standard was designed for competitive auto racing while the M standard was for motorcycling and other motorsports. There are three major differences between them:
SA standard requires pass a flammability test while the M standards do not. Generally speaking, SA and SAH helmets will have a Nomex lining and a yellow Nomex chin strap.
SA standard allows for a narrower visual field than the M standard (Some SA certified helmets may not be legal for street motorcycle use).
SA standards include a rollbar multi-impact test while the M standard does not.
Open Face vs Closed Face
Open face helmets are preferred in cars with air bags. This is because the airbag inflates into the same space as the chin/face protection on a closed face helmet, which pushes the occupant’s head up and back (ouch!) and lessens the effectiveness of the airbag. Closed face helps are preferred in cars without airbags due to the additional impact protection they provide.
Changes to Snell 2015 SA helmet standards
Snell 2015 SA helmets are now available in the marketplace (it was a slow start, but they are here now). We strongly recommend updating your helmet to a 2015 due to two significant changes that are incorporated in the Snell 2015 SA standards:
1) Head-and-Neck Restraint (HANS) compatibility across all helmets. This comes in the form of the pre-installed M6 hardware that was previously required only on helmets with a Snell/FIA rating (formerly known as the SAH-rating).
2) New impact testing is being used that mimics FIA-testing. Low velocity testing is now required; as is protection against lower impact points, such as strikes against window frames and other lower structures.
Can I use a DOT helmet?
NO. The DOT standard (meaning United States Federal Motor Vehicle Safety Standard #218) is considered to be lesser than current Snell Memorial Foundation standards from both functional and compliance perspectives. With respect to function, the DOT standard was developed in 1972 and remains virtually unchanged except for a minor revision to the testing process in 1988; whereas the Snell standard is revised every 5 years and is continually evolving based on new information on how to prevent brain injuries. For example, the latest 2015 Snell standard has significant improvements in low-velocity impact protection and low-lateral impact protection which DOT does not require.
More important, however, is the issue of compliance with the certification standard. Snell independently tests samples of each and every helmet design before providing certification, and then performs ongoing spot-checks of each helmet design throughout its production life. Manufacturers who use the ECE R22-05 standard must also submit their helmets to an independent third-party for similar testing. But with DOT, there is no third-party verification or testing requirements, meaning that companies certify their own helmets. BUT DO THEY? NHTSA conducts random tests on about 40 sample helmets every year for compliance. During the years 2004-2008, NHTSA found 28% of so-called DOT-approved helmets failed performance testing. This is an unacceptable failure rate.
Even without knowing you, we are certain you are worth the cost of a helmet that will actually protect you when you need it.