i am certainly no expert, but i have recently been a head on crash (someone lost control of their car and hit me). the combined speed was probably about 55mph. in the crash, the driver airbag didn't deploy. the driver/owner bought the car used and assumed the airbag light on the dash was a glitch! it wasn't. i don't think the airbag existed. anyways, i was wearing a seatbelt and didn't even reach my airbag. i was fine. the driver who had no airbag, was also wearing a seatbelt and was also fine. having been in that crash, its hard to imagine what sort of impact would be required for a front airbag to come into play IF you are wearing your seatbelt. my opinion since then that a seatbelt is the most important factor. however, that being said, i think the SIPS airbags do have merit, as seatbelts dont really help your head from smashing into the side of the car.