Air bag

Air Bag

An air bag is a vehicle safety device designed to inflate rapidly during a collision to provide a cushion between the occupants and the interior of the vehicle. Air bags are part of a vehicle's Supplemental Restraint System (SRS) and work in conjunction with seat belts to enhance occupant protection.

History

The concept of the air bag dates back to the early 1950s, with the first patents filed by American engineer John W. Hetrick and German engineer Walter Linderer. However, it wasn't until the 1970s that air bags began to be implemented in vehicles, with General Motors offering the first production air bag in the 1973 Oldsmobile Toronado.

Functionality

Air bags are designed to deploy in the event of a moderate to severe frontal or side collision. The system consists of:

• **Sensors**: These detect a collision and send a signal to the air bag control unit.
• **Inflator**: Upon receiving the signal, the inflator ignites a chemical propellant, producing a rapid expansion of gas.
• **Air Bag Module**: The gas inflates the air bag, which is typically made of a nylon fabric, within milliseconds.

The rapid inflation of the air bag provides a cushion that helps to reduce the risk of injury by distributing the force of the impact over a larger area of the body.

Types of Air Bags

• **Frontal Air Bags**: These are located in the steering wheel and dashboard and are designed to protect the driver and front passenger in a frontal collision.
• **Side Air Bags**: These are installed in the seats or doors and protect the torso and head in a side impact.
• **Curtain Air Bags**: These deploy from the roof lining and protect the heads of occupants in both front and rear seats during a side collision.
• **Knee Air Bags**: These are designed to protect the knees and legs of the driver and front passenger.

Safety and Regulations

Air bags have been shown to significantly reduce the risk of death and serious injury in vehicle crashes. In the United States, the National Highway Traffic Safety Administration (NHTSA) mandates that all new vehicles must be equipped with frontal air bags. Similar regulations exist in other countries.

Limitations and Risks

While air bags are a critical safety feature, they are not without risks. Improper use, such as not wearing a seat belt, can lead to injury from the air bag itself. Additionally, air bags can pose a risk to children and small adults if they are seated too close to the deployment zone.

Also see

• Seat belt
• Crash test
• Vehicle safety
• Supplemental Restraint System

There are three main statistics for which vehicle safety can be compared: (Data taken from UK transportation)

Deaths per billion journeys
Bus: 4.3
Rail: 20
Van: 20
Car: 40
Foot: 40
Water: 90
Air: 117
Bicycle: 170
Motorcycle: 1640

Deaths per billion hours
Bus: 11.1
Rail: 30
Air: 30.8
Water: 50
Van: 60
Car: 130
Foot: 220
Bicycle: 550
Motorcycle: 4840

Deaths per billion kilometres
Air: 0.05
Bus: 0.4
Rail: 0.6
Van: 1.2
Water: 2.6
Car: 3.1
Bicycle: 44.6
Foot: 54.2
Motorcycle: 108.9