As said in the previous post, airbags were first introduced to protect people who would not use seatbelts. Using a properly adjusted seatbelt will give good protection in most frontal impacts, the main advantage of the SRS system is the seat belt tensioners which fire on impact and pull you back into the seat reducing the risk of contact with wheel,dash,screen. Side impact is I feel the most lethal incident these days,and although strenghthening bars and curtain airbags can give some protection, if you are hit side on by anything travelling at speed you are going to be very lucky to survive. So keep you wits about you when pulling out at junctions.
Geo.