How Do Airbags Work

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Car airbags have been a popular component in vehicles for decades, but they aren’t just used to prevent injury in a collision. They are an important component of your vehicle’s safety system, and they serve a variety of purposes depending on the type of vehicle you drive. The safety of the driver, front-seat passenger and any rear-seat passengers is the most important thing, but airbags also serve to protect the vehicle itself. In this article you’ll understand that how do airbags work.

What is an Airbag?

An airbag is a pillow-like safety device that inflates during the events of a frontal crash of an automobile. The purpose of employing the air-bag is to provide a cushion for the occupants’ bodies. Thus, it prevents their direct collision with the inner objects such as the steering wheel or dashboard. Therefore, it is one of a modern-day car’s most vital safety features.

How Do Airbags Work
Car fitted with Airbags

Why Do Car Crashes Do Damage?

Everything in the world is controlled by the laws of physics and, more specifically, the laws of motion. A moving car is not an exception. All objects have mass and when they move have velocity. Anything that has mass and velocity has kinetic energy, and the heavier the object and the faster it’s moving, the more kinetic energy it has.

In the case of a moving car it’s fine until you suddenly want to stop or until you crash into something. Then all the energy has to go somewhere. Even though cars are designed to crumple up and absorb impacts, their energy still poses a major risk to the driver and passengers.

How Airbags Help?

Airbags are designed to prevent injuries in the event of a collision. Depending on the vehicle, the airbag may be released from the dashboard, the steering wheel or other areas of the vehicle. Although these devices are exceptionally simple in design, airbags feature innovative technology. In order to be effective, the airbag must open faster than a car can crash. While you may be hitting another vehicle at 60 mph, your airbag is moving at a speed of 200 mph to keep up.

How Do Airbags Work?

When a car hits something, it starts to decelerate (lose speed) very rapidly. An accelerometer (electronic chip that measures acceleration or force) detects the change of speed. If the deceleration is great enough, the accelerometer triggers the airbag circuit. Normal braking doesn’t generate enough force to do this.

The airbag circuit passes an electric current through a heating element which in turn ignites a chemical explosive. Older airbags used sodium azide as their explosive; newer ones use different chemicals. As the explosive burns, it generates a massive amount of harmless gas (typically either nitrogen or argon) that floods into a nylon bag packed behind the steering wheel.

How Do Airbags Work
Working of an airbag

As the bag expands, it blows the plastic cover off the steering wheel and inflates in front of the driver. The bag is coated with a chalky substance such as talcum powder to help it unwrap smoothly. The driver (moving forward because of the impact) pushes against the bag. This makes the bag deflate as the gas it contains escapes through small holes around its edges. By the time the car stops, the bag should have completely deflated.

Types of Monitors

Types of Airbags

There are broadly four types of airbags serving their specific purpose.

1. Side Airbags

These are usually located in the backrest of the seat, and inflate between the door and the seat occupant. Side airbags are estimated to reduce serious chest injuries in side-impact collisions by approximately 25%. There are 2 types of airbags. First is the torso airbag which protects your torso and the second is the curtain airbag which deploys from the car ceiling protecting your head.

2. Front Airbags

Typically deploy from the steering wheel to protect the driver from striking other parts of the car in a frontal crash. These airbags are designed to be used in conjunction with seatbelts and do not offer protection in the event of a side impact crash.

3. Knee Airbags

These are installed in the lower portion of the dashboard, directly in front of the passenger’s knees. When a collision occurs, they inflate to fill the space between the dashboard and the passenger’s lower legs.

4. Inflatable Seat Belt

This technology functions much like an airbag and was designed to protect the fragile bones of back seat passengers, like children and the elderly, who are more vulnerable to head, chest and neck injuries.


Airbags are one of the most effective safety technologies in the world. It is considered as one of the best inventions of the 20th century. There are several other safety innovations but none of them are as effective as airbags.

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Image Credit: Airbag vector created by brgfx –

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