Does depend on the vehicles involved. Short of a NASCAR approved roll cage, you do a head on with a semi truck at a closing speed of 120 mph (60 mph for each vehicle) and you are going to die, be a total basket case, or in a vegetative state for the rest of your life. Seat belts and air bags will not help much if at all. Dental records might! There is just no getting around that 80,000 lb of truck and load, no auto or pickup occupant stands much of a chance except maybe with a glancing strike. If one is lucky, it might get tossed out of the way. A direct head on, chances are good that the truck is going to go right over the top of the car. We can try as we like, but physics comes into play nonetheless. Recent accident on I-80 just west of Des Moines, a Des Moines police vehicle with two officers transporting a inmate from one of the correctional facilities did a head on with a car going the wrong way on the interstate. All occupants in both vehicles died at the scene. Seat belts and bags did nothing to prevent that tragedy.
It has caused me to wonder sometimes, if people are not more aggressive in their driving because of a false complacency that they will be protected by belts and bags. Might be one of those unintended consequences of all that "safety". We can pile on the safety stuff, but stupid wins every time.