22nd December 2025
Airbags are one of those car features you rarely think about, until you really need them. They sit quietly behind the scenes, hidden in your steering wheel, dashboard, doors, and seats, ready to act in a split second if the worst happens. First introduced in the 1950s, airbags have been a mandatory safety feature in all new UK cars being sold since 1998. These inflatable bags can be found in many areas of your car’s cabin, from the steering wheel and dashboard to the rear passenger seats.
Understanding how airbags function can help you appreciate their role in vehicle safety, recognise warning signs of a fault, and know when to seek professional advice.
A car airbag is designed to protect occupants during a serious collision by cushioning the impact between the person and the hard interior of the vehicle. It works alongside seatbelts, not instead of them, to reduce the risk of severe head, chest, and upper body injuries.
Airbags deploy in milliseconds and deflate just as quickly, which is why they can look dramatic but still prevent serious harm.
A car airbag is typically made up of:
If your vehicle is involved in a collision, the airbags should activate quickly. The gyroscopes and accelerometers in your car can detect the forces the vehicle is subjected to. They can determine whether the airbag can be deployed in an accident.
It is easy to picture a car airbag inflating from your steering wheel.
However, you can find airbags in many places inside your car’s cabin:
Contrary to popular belief, airbags do not deploy in every accident. They are triggered only during collisions that meet specific criteria.
Your car is fitted with impact sensors that monitor sudden changes in speed and force. When these sensors detect a collision severe enough to cause injury, they send a signal to the airbag control unit. If the data confirms deployment is necessary, the system activates instantly.
Minor bumps, low speed impacts, or gentle braking will not cause airbags to inflate.
Once triggered, the process happens incredibly fast. An electric signal ignites a chemical reaction inside the airbag inflator. This reaction produces nitrogen gas, which rapidly fills the airbag.
The bag bursts through its cover and inflates in front of the occupant in around 30 to 40 milliseconds. As the person makes contact with the airbag, it begins to deflate through small vents, absorbing energy and reducing impact force.
This carefully controlled inflation and deflation is what makes airbags effective rather than dangerous.
Modern vehicles often have multiple airbags positioned throughout the cabin.
Front airbags protect the driver and front passenger in head on collisions. Side airbags reduce injury during side impacts, particularly to the chest and abdomen. Curtain airbags deploy from the roof lining to protect the head in side collisions or rollovers. Some vehicles also have knee airbags to limit leg injuries.
Each airbag is designed to deploy only when needed, depending on the type and direction of impact.
Airbags are designed to work with seatbelts, not replace them. A seatbelt holds you in the correct position during a crash, allowing the airbag to protect you effectively.
Without a seatbelt, an airbag can deploy too close to the body, increasing the risk of injury. This is why wearing a seatbelt remains essential, even in cars with advanced airbag systems.
If the airbag warning light appears on your dashboard, it means the system has detected a fault. This could involve a sensor issue, wiring problem, control unit fault, or a previously deployed airbag that has not been replaced.
When this light is on, the airbags may not deploy correctly in an accident. It should never be ignored, even if the car seems to be driving normally.
Airbags are designed to last the lifetime of the vehicle, but they are still part of an electronic system that can develop faults. Moisture, corrosion, wear to wiring, or previous accident damage can all affect performance.
Regular vehicle servicing helps identify warning signs early, especially in older cars or vehicles that have been involved in a collision.
Your car’s airbags should only be switched off if it presents a danger to vulnerable passengers, like babies and young children.
If you decide to switch off the airbags, you can do so via a switch inside your car’s cabin. We recommend that when driving with babies or children travelling in the front passenger seat that you deactivate the front passenger airbag, for older children using front facing car seats or booster seats you should ensure that they sit in the rear of the vehicle. Also, be sure to turn the airbags back on when transporting other older children or adult passengers in the front seat to reduce the risk of potential injuries if your car is involved in an accident.
No, driving a car with a deployed airbag will affect other safety features while compromising your vehicle’s steering. However, if you have been involved in a severe collision that activated the airbags, you should not drive it until it is checked by a trained mechanic.
Is your vehicle’s MOT due soon? Are you wondering if it is roadworthy? Our article covers what you need to know about what makes a car roadworthy. Book your free 7-point safety check at your nearest Merityre branch across South-East England today.
During an MOT, the airbag warning light is checked. If it stays illuminated or fails to come on at all, the vehicle will fail the test. This makes it important to address any airbag system warnings well before your MOT is due.
At Merityre, we understand how important vehicle safety systems are. If your airbag warning light is on or you are concerned about how your car’s safety features are performing, our technicians can carry out checks and diagnostics to identify issues.
Alongside tyres, brakes, and servicing, keeping safety systems in working order helps protect you and your passengers every time you drive.
If something does not feel right, booking a service can give you confidence that your vehicle is in good condition. Contact us or find a branch near you.