Bike helmets can't be sold in the USA unless they meet CPSC standards.

Unfortunately, CPSC doesn't involve any independent testing. Snell does, but since CPSC became the law, few manufacturers shell out for Snell testing.

Unlike the recent exposés of motorcycle helmets and the drastic revision of Snell motorcycle standards as a result, CPSC and Snell standards are quite similar.

BHSI has a handy comparo on their site.