If you're riding downhill or aggressive mountain bike trails, ASTM F1952 certification is worth seeking out. This standard tests helmets at significantly higher impact energies than the basic CPSC or EN 1078 certifications that cover everyday cycling. It's designed specifically for the harder hits and higher speeds common in downhill riding.
Most ASTM F1952-certified helmets are full-face models with extended coverage, which makes sense given the risks of the discipline. A standard CPSC-certified trail helmet simply isn't built to absorb the forces involved in a high-speed off-road crash.
Think of it this way: CPSC is the legal minimum for selling a bike helmet in the US, but ASTM F1952 goes further for the specific demands of downhill. If you're riding lift-accessed trails, bike parks, or steep technical descents, that extra margin of protection really matters.