Introduction

Though instrumental in saving countless lives, the airbag is relatively new in the timeline of the history of cars. The history of this very important safety device is even shorter in India, it was made mandatory only very recently. What does an airbag do? How does it work? And why should you be aware of it? Let’s answer these questions.

The air cushion concept

The air cushion

The ability of a cushion of trapped air to soften a blow is easily demonstrable. Fall face first in a bouncy castle and you wouldn’t feel a thing, get hit with a balloon and you wouldn’t wince in pain. But applying that logic to prevent people from hitting a hard surface, like the inside of a car during an accident, could make things worse.

Delays

Technology and apprehension delay innovation

While the first patents for an airbag device to protect occupants of a car/airplane were filed as early as 1920, the technology was not ready for it. Unlike modern fiber-based bags, early prototypes used rubber. The explosive device used to fill up the bag with air was developed 40 years later and the first crash test sensor was invented in only 1967.

In 1974, GM would become the first manufacturer to offer airbags as optional equipment. While some manufacturers followed suit, they also lobbied against the technology stating cost and it being ‘inappropriate’. Just like the seatbelt, the airbag was treated with apprehension by many motorists, regarding it as just another cash grab method by manufacturers rather than actual safety equipment. It would take another decade before automotive safety was taken seriously enough in most developed nations and airbags were made mandatory fitment in cars sold in those markets.

SRS Airbags?

An airbag is supplemental

An airbag in itself cannot save one in case of an accident, it works with the seatbelt to lessen the impact of a crash. Airbag systems are designed not to work to their full potential, or not at all in older designs, if the occupants do not wear their seatbelts. Unbelted occupants can receive more harm from the inflating bags and can even bounce off in uncontrollable directions causing more injuries. Lesson? Wear your seatbelt at all times when in a car.

How do they work?

How do they work?

The airbag system of a car, in very simple terms, consists of multiple sensors and the airbag unit itself. The sensors can detect deceleration, vehicle position in relation to impact, vehicle speed, seat occupancy, weight of occupants etc. and more depending on how complex they are. The airbag is designed to slow down the deceleration experienced by the occupant, in turn lowering their injuries.

The airbag unit consists of a folded fabric bag and a chemical explosive. The airbag’s size and shape are dictated by where they will be placed in the car, but all of them are designed to withstand sudden expansion and have holes behind them which vent out the air to further soften the blow. The materials placed over the airbag units, like the centre of the steering wheel or portion of the dashboard, are designed to tear relatively easily compared to the surrounding area.

In modern airbag systems, complex, often closely-guarded algorithms decide when and how the system should be triggered. The system can also trigger multiple airbags if equipped, trigger the seatbelt pre-tensioners and even close windows and sunroofs in some cases to lessen the impact and after-effects of a crash.

Common types of airbags

Common types of airbags

Driver airbag - placed in the horn pad of the steering wheel, this airbag protects the driver’s head from colliding with the steering wheel during a crash. These are usually circular in shape when deployed and cover the steering wheel completely.

Front passenger airbag - Placed behind the dashboard, these protect the head of the front passenger from hitting the dashboard. These are always much bigger in size than the driver airbag as they have to account for the extra distance between the dashboard and the passenger.

Side torso airbag - The torso airbags are placed on the outer side of the front seats and/or rear seats and prevent the occupants body, not the head, from impacting the door panel.

Side curtain airbag - deployed from the roof, these airbags protect the occupants head from hitting the roof, door frame and windows during a sideways collision.

Mandatory equipment in India?

Indian regulations catch up, sort of

Airbags had not been part of mandated safety equipment for cars sold in India till April 2019. Manufacturers had been voluntarily offering airbags in their cars, some more actively than others. The first made-in-India car to offer airbags was the Telco-assembled Mercedes-Benz E-Class (W124) in 1995, it took a government mandate to force Maruti to offer only one airbag as standard last year.