A: HJC makes both, Snell and D.O.T. approved helmets. However the Flip-Up style helmets can only be certified as D.O.T. This holds true for all brands distributed in the United States. HJC does make Snell rated helmets in their Full Face models.
The Snell Memorial Foundation does not approve the Flip Up helmets for a couple of reasons. When the chin bar is in the up position, there is a thinner area in the temple area of the shell that does not meet the strict impact standards by Snell. Also, Unlike a full face helmet, the chin bar could catch on something if the rider was wearing the helmet in the Flip-Up position.
Hope this answers you question.
The Helmet Shop