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What they are and what they do
Airbags are a crash protection feature. They consist of a bag, usually made from woven nylon or polyester, which will deploy during the impact of a crash. Cars most commonly have airbags installed in the steering wheel (refer to point 1 on diagram on right) and dashboard (point 2). However, side-impact airbags can also be found in seats (point 3) or above the side windows (point 4).
Airbags commonly work together with seatbelts as a constraint to prevent passengers from being ejected from a vehicle. However, they also act as a protection barrier and help to prevent injuries caused by hitting the dashboard or steering wheel during a collision.
How they work
Similar to seatbelts, airbags also relate to Newton’s theory of inertia. In the event of a car crash the car is suddenly stopped, and without the use of a seatbelt and airbag, the passenger would continue to move forward at the same speed as before. However, in contrast to seatbelts, airbags help to decrease the passenger’s momentum instead of holding them in place.
Airbags are made up of three main components:
- The bag, which is made of nylon or polyester and folded into numerous locations around the car.
- The sensor, which sends a message to the inflation system when the bag needs to inflate. The sensor usually requires a minimum force of hitting a brick wall at 16km/h to sense that the bag needs to deploy.
- The inflation system, which inflates the bag with nitrogen gas at just over 300km/h.
Development
When airbags were first released, they were marketed as a replacement for seatbelts. However, it has been realised that having both seatbelts and airbags provides the best protection to passengers.
Until recently, airbags were usually only included in the front of vehicles. However, car manufacturers have continued to alter the positioning and placement of airbags in vehicles, and have discovered that having them on the sides helps to add extra protection in side-on collisions or rollover accidents. Today, most cars are equipped with up to eight airbags.