From the pointy board:
For strictly autocrossing, an open-faced "M" helmet should be just fine. For open track I'd want a full-faced SA helmet. In fact, even though I've already got an SA2000 Simpson Super Bandit, I'm thinking about buying one of the Bell Tourlite 2 M2000 helmets on sale here, both to have a more comfortable helmet for midsummer autocrossing, and to potentially sidestep any upcoming SCCA regulations concerning full-faced helmets and airbag equipped cars.Originally posted by Dave_W:
"SA" stands for "Special Application" and indeed uses fire-resistant lining material. Both the M and SA certifications use impact tests against flat, hemispherical, and "edge" anvils. In addition, the SA uses an impact test against a "rollbar" anvil. For full details, see the Snell Memorial Foundation website.