One of the biggest advances in passenger safety in automobiles since the seat belt is the airbag. Since being introduced over 50 years ago, airbags have become very common in passenger vehicles — and required by law in new vehicles. In this activity, you will learn all about airbags.

 An airbag is rolled up inside the steering wheel and the passenger-side dashboard of a car. How do airbags work? Sensors in the vehicle detect sudden deceleration or braking. If the driver brakes suddenly and severely, the sensor sends an electrical signal to a chemical propellant that produces nitrogen gas to inflate the airbag. This happens very quickly — in about 1/20th of a second!

As a result, the people in the front seat — IF they are correctly buckled in with their seat belts—are cushioned from hitting the steering wheel or dash.

When airbags were first introduced, however, the bags caused some injuries and deaths to motorists. The early models, the "first generation airbags" inflated with so much force that they caused injuries to people, especially children, who were seated too close to the airbag. Most cars now have "second generation airbags" that deploy with less force. They are less likely to injure people who are sitting too close to the airbag when it inflates.

 Recently, "third generation airbags" can sense the level of power needed to inflate safely based on the size of the passenger, the position of the seat, whether the passenger is wearing a seat belt, and the severity of the braking of the vehicle.

The key to airbag safety is to wear your seat belt properly and avoid sitting too close to the airbag. Keep the seat as far back from the dash as possible. Children under 13 should not sit in the front seat. A rear-facing baby seat should never be in a seat where there is an airbag.

In addition to airbags, car manufacturers have made other improvements over the years to the interior of cars:

• better steering wheels that absorb energy to make less forceful impact on the driver in a collision

• dashes that are more energy absorbent, using softer materials for padding

• safety windshield glass that shatters but does not break under most circumstances