Are Hövding helmets safer than regular helmets?
That's the inflatable "airbag" helmet.  It's main claim to fame is that it isn't really a helmet, but sits in a (dorky looking) collar around your neck until needed.

First off, I'm skeptical that the helmet could be tested to most bike helmet standards at all, since the test procedures would not be designed for such a helmet.  So it's pretty much impossible to say if it "meets standards", much less is better than others. For helmet testing info smf.org/standards/b/b90astd (thanks to @Ken Hiatt)

Secondly, the trigger mechanism can't rely (as a car airbag does) on waiting until impact to activate.  So it must trigger based on sudden movements of the head and upper body.  The reliability of this is questionable.  (Keep in mind that a substantial number of head injuries while cycling are due to simply falling off the bike -- the old "forgot to unclip" problem, eg.)

Third, given the iffy nature of the trigger mechanism, false triggering would seem likely, and having the helmet suddenly inflate in a critical situation could be extremely disorienting and lead to an accident that would not otherwise happen.