Airbags Explained

An airbag is a type of vehicle safety device and is an occupant restraint system. The airbag module is designed to inflate extremely rapidly then quickly deflate during a collision or impact with a surface or a rapid sudden deceleration. It consists of the airbag cushion, a flexible fabric bag, inflation module and impact sensor. The purpose of the airbag is to provide the occupants a soft cushioning, and restraint during a crash event to prevent any impact or impact-caused injuries between the flailing occupant and the interior of the vehicle. The airbag provides an energy absorbing surface between the vehicle's occupant and the vehicle.

Modern vehicles may contain multiple airbag modules in various configurations including:

Driver airbag module

Passenger airbag module

Side curtain airbag module

Seat-mounted side impact airbag module

Knee bolster airbag module

Inflatable seat-belt modules

Front Right Side Airbag Sensor

Front Left Side Airbag Sensor

Pedestrian airbag module

Let’s understand more about this wonderful life saving feature of your car.

How Does the Airbag work?

The Airbag inflation module contains a heating element that 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 does the Airbag sensor work?

An airbag sensor is responsible for detecting sudden deceleration in a collision i.e. when the vehicle decelerates with a force equal to hitting a solid object at a speed of more than 25km/h. That's similar to a 50km/h crash into an identical car. It sends a signal to the airbag computer which uses the vehicle speed, yaw, seat belt and ECU to determine if an airbag should deploy in a crash. There's two types of mechanical airbag sensors, the cam type and ball and tube style.

What is an SRS Airbag?
The SRS Airbag System is designed to supplement the seatbelt system and improve occupant protection in certain type of crushes. Airbags supplement the seat belt and enhance passenger safety in certain types of collision.

Where is the Airbag Sensor Located?

These sensors are located throughout your vehicle, detect a collision and trigger the airbags to go off. They are usually found at the front of the vehicle, behind the front fender, to detect a frontal impact, and in the side columns to detect a side impact.

How safe are Airbags?

The National Safety Council (NSC) estimates air bags saved more than 1,040 lives in 1998. However, there were almost 100 children killed by air bags during the same year. These deaths were because of children sitting in the front seat, being improperly fastened by seat belts, or not wearing seat belts at all.

Why are Airbags dangerous for children?

Though airbags can save lives, they can be dangerous for babies and young children. An airbag inflates almost instantly, in as little as 20 milliseconds, after a crash. The thin nylon airbag gets an immediate injection of hot nitrogen gas, which makes it expand so quickly that it forces it out from the dashboard at about 160 mph (257 km/h). So it poses a clear risk to a baby in a rear-facing seat, who is directly in the airbag's line of fire.

What age of child can sit in the front seat of the car?

All children aged 12 and under should ride properly buckled in the back seat. Airbags can kill young children riding in the front seat. Never place a rear-facing car seat in the front seat or in front of an airbag.

How do we know if the car we are buying is safe enough?

The safety of cars are rated by the  NCAP ratings and similar. Euro NCAP introduced the overall safety rating in 2009, based on assessment in four important areas: Adult protection (for the driver and passenger); Child protection; Pedestrian protection and Safety Assist technologies. The overall star rating was introduced to add more flexibility to the ratings’ scheme, which had been used since 1997.

What ratings do cars sold in India use?

Currently the cars sold in India use the EURO NCAP ratings. The Bharat New Vehicle Safety Assessment Program (BNVSAP) is a proposed New Car Assessment Program for India. Cars sold in the country will be assigned by star ratings based on their safety performance. It will be implemented in phases, according to the plans being drawn up by the National Automotive Testing and R&D Infrastructure Project. It is the 10th NCAP in the world and is being set up by the government of India.

It is proposed that this BNVSAP would start the official testing from October 2017 onwards. The car testing protocols is defined by ARAI as follows:

Frontal offset testing (64 kmph proposed)

Side impact testing

Pedestrian protection testing

Rear impact testing

Child dummy dynamic crash testing

Points would be awarded to the car based on the safety features in the car like ABS, seat belt reminders, child lock, and Electronic Stability Control.