Probably both but like anything else I think you could make the data look however your agenda wants if you monkey with the definitions of terms. A seat-belt is

Probably both but like anything else I think you could make the data look however your agenda wants if you monkey with the definitions of terms. A seat-belt is a great way to wind up seriously injured when you otherwise would have died and boring old frontal airbags tend to make serious injuries less severe and minor injuries more severe.