Auto Safety Questions: How Air Bags Work

The automobile airbag has been available since the 1980s, technological advances are helping them become more effective.

When airbags first became available in vehicles in the 1980s, they had the same dubious reputation as the first seatbelts. Consumers feared that they would cause more harm than good, exaggerating their potential to harm and even kill drivers and passengers. Although these accidents occurred on occasion and still do, though less frequently, the life-saving potential of airbags cannot be disputed. In fact, deaths from front-end collisions are decreased by thirty percent in automobiles with airbags. Better yet, as airbag technology improves, front and rear seat passengers are also more protected. The following provides a brief history of the airbag as well as an explanation of how it works.

The history of airbags began in World War II, when they were first implemented to provide protection during airplane crash landings. Although they had little in common with the modern airbag, these inflatable devices were designed to deploy to limit the amount of damage done to pilots. Decades later, the US government saw their potential in commercial vehicles. Although they found that the introduction of seatbelts provided increased safety, the impact of front-end collisions still often seriously injured or killed passengers. For this reason, they turned their attention to the crude airbags of previous decades. When a car hits an object head-on, it immediately stops. However, any objects that are unrestrained in the vehicle continue to move, including people. This is because they maintain momentum from the moving vehicle, even after it ceases to move. When a body is thrust forward, the impact of hitting a steering column or dashboard can be deadly.

Manufacturers knew that they needed to stop a person's movement in a crash in such a way that no damage was done. An airbag provides a cushion, slowing a person evenly by inflating a bag across the torso. In theory, experts found this to be an exceptional idea, but they did not have a way to make it work in a car. There is limited space in vehicles for storage, so there is no room for a canister of gas. Without this gas, the airbag cannot inflate. Also, they did not know how to create inflation rapid enough to save a person from the impact. In a car crash, there is only a fraction of a second (1/25 to be precise) for the bag to deploy. Luckily, they developed a solid propellant canister, the contents of which can be converted into a gas. In order for this to happen, an impact of at east 10 mph must occur, which triggers a sensor mounted in the airbag. This sensor receives news from the accelerometer if a collision over 10 mph occurs and flips the inflation system switch. Once activated, this system ignites the contents of the propellant canister, converting them to gas. Gas rapidly inflates the nylon airbag, causing it to deploy at speeds up to 200 mph.



Before a driver can blink, their airbag will appear during a crash. With proper positioning, it will make contact at the chest, slowing their motion and quickly deflating. The bag is designed with small air holes through which the gas can escape. An airbag in perfect working order thus prevents the head and neck traumas responsible for most car accident deaths and serious injuries. However, in order for the bag to work safely and correctly, some precautions must be taken. Drivers should position the steering wheel bag so that it points toward the chest and is ten inches away from the sternum. Children under twelve years of age should sit in the back in an approved child's seat with lap belt. Infants (children under 1 year and twenty pounds) should sit in the back in a rear facing infant seat. The powerful impact of an airbag can be deadly to children, so all steps should be taken to keep them away from it. For adults who are too small to position the airbag properly, as well as for those who must transport kids in the front seat, it is possible to have airbag On/Off switches installed.

Although airbags in steering columns and dashboards help save lives in front-end crashes, they do nothing to protect passengers during side-impact collisions. For this reason, manufacturers are constantly creating new airbags designed to buffer blows to car doors. The major concern in this area has to do with how thin doors are in comparison to the front end of a car. There is substantially less time for a side airbag to react -- a mere five to six milliseconds. One company has bypassed this problem by creating seat-mounted airbags for backseat passengers. These devices only deploy when a sensor under the front seats is triggered by a blow over 12 mph. Another group places bags in the door to provide a larger cushion. This airbag also stay inflated for a few seconds longer. The reason behind this design is that side-impact crashes often lead to multiple car pile-ups. If the car should be struck again, the airbag will still be present to protect passengers. With these innovations along with the 1998 law requiring that airbags be included in all new vehicle models, driving safety continues to improve.

The life preserving benefits of airbags are phenomenal when they are used in conjunction with seatbelts. It is true that they can be dangerous when used improperly, but multiple government-funded studies have proven their effectiveness. In future years, experts believe that car safety will multiply, as not only seatbelts and front dash airbags become standard equipment. One day, every side of your vehicle may contain one of these inflating life saving devices.

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