Even though air bags have become standard safety technology in virtually every vehicle, they still remain mysterious. To kick off our new Q & A feature, it seemed only natural to pay the air bag its due and find out more about this life-saving device.
1. How does an air bag work?
In moderate to severe frontal or near frontal impact, you can come into contact with the steering wheel or instrument panel. Air bags are designed to supplement the protection safety belts provide. When an air bag is deployed, it distributes the force of the impact more evenly over your upper body, stopping you more gradually.
In collisions where your body's motion is not toward the steering wheel or instrument panel, the air bag is not designed to inflate. These types of collisions include rollovers, rear and side impacts.
2. At what speed will an air bag deploy?
Air bags inflate as fast as 320 km/h (200 mph), and with great force. U.S. Federal regulations currently require air bags to inflate and restrain an unbelted dummy representing the average adult male in a crash test into a concrete barrier at 48 km/h (30 mph). To meet this federal requirement, an air bag must inflate in a split second (about 1/30th of a second). This is faster than a blink of an eye. It is so fast you can't see it happen. In the crash test the air bag must be able to restrain the force that the unbelted dummy, which weighs about 75 kg (165 pounds), applies to the air bag. That force can be as much as 907 kg (2000 pounds).
3. When will an air bag inflate?
Your air bag will inflate only if the rate of deceleration is above the system's designed "threshold level." If your vehicle hits something that does not move, like a wall or guard rail, the threshold level is about 15 to 24 km/h (9 to 15 mph), depending on the specific vehicle design. If your vehicle hits something that moves, such as a parked car, the threshold level will be higher. Inflation is determined by the angle of the impact and how quickly the vehicle stops or decelerates in front-angle impacts.
4. What happens after an air bag inflates?
An air bag inflates and deflates so quickly that you may not even realize the air bag deployed. After deployment, some air bag components will be hot for a short time. The parts of the bag that you come into contact with may be warm, but not too hot to touch. Smoke and dust will come from the vents in the deflated air bags. Air bag inflation doesn't prevent you from seeing or being able to steer the vehicle, nor does it stop people from leaving the vehicle.
In many crashes severe enough to inflate an air bag, windshields are broken because the vehicle itself deforms. Additional windshield breakage may also occur from the right front passenger air bag. Once your air bag has been inflated, the system needs to be replaced. Without repair, the air bag system will not provide protection in another crash.
5. How reliable are air bags?
The track record of air bags indicates that they inflate when they're supposed to, in moderate to severe frontal or near frontal crashes. Air bags are designed to inflate in crashes equivalent to hitting a wall at speeds above a range 15 to 24 km/h (9 to 15 mph), not when cars go over bumps or potholes. They are reliable for the life of the vehicle, but are designed to inflate only once. Replacement of the system is required after the air bag has been inflated.
To help keep you safe, General Motors vehicles feature Next Generation air bags. These air bags deploy with less force than older versions, helping to prevent injuries to drivers and passengers.
Look for future installments of our Q & A feature soon. We've just scratched the surface of the world of air bags, and we know there are a lot more questions out there about other car features.