Everything You Need to Know About Airbags
- Car ownership
- How it works
FixMyCar explains how airbags work, where you can find them, and why they're important.
Book car repair nowEllie Dyer-Brown
Tuesday February 04 2025
9 min read
Imagine you’re driving to work, the same route you take every day. But this time, something out of the ordinary happens. Another driver pulls out of a junction without looking. You try to brake. It’s too late. They’re heading right for you. What happens next?
The answer, fortunately, is that your car’s safety systems come into play: seatbelts, crumple zones, and airbags.
This guide explores what airbags are, where to find them, and how they work.
Contents
How do airbags inflate so quickly?
What does it feel like when an airbag goes off?
How safe and effective are they?
Should you service your airbags?
Can I remove airbags myself or switch them off?
What are airbags?
Airbags are inflatable cushions that quickly fill with air during a collision to protect drivers and passengers. Since their introduction in the 1950s, they have saved thousands of lives and are fitted to almost every modern car.
They absorb energy and prevent vulnerable body parts from hitting hard surfaces, such as the dashboard, which could otherwise cause painful and sometimes life-threatening injuries.
American data shows frontal airbags have saved over 50,000 lives in 30 years.
How do airbags work?
Modern airbags consist of three main parts:
An inflation module
Impact sensors
The bag
Impact sensors are located around the car to detect movements indicating the vehicle has been involved in a collision. The sensors then trigger a small explosive device within the inflation module, which inflates the bag with air to protect the car’s occupants.
Airbags immediately deflate after impact so that people can leave the car promptly and emergency services can assist if needed.
Some modern airbag systems are advanced enough to detect the severity of the crash and inflate the airbags to the correct pressure based on this information. Pretty clever, right?
Airbags are also called supplementary restraint devices (SRS) because they work with seatbelts to control how a crash impacts your body.
Find out what to do if you’ve been involved in a car accident.
What speed do airbags deploy?
Newer airbags have a seatbelt sensor and use an advanced algorithm to determine whether to deploy in a crash.
With an unfastened seatbelt, a front airbag will typically deploy when the crash is equivalent to an impact into a rigid wall at 10-12mph. With a fastened seatbelt, a front airbag will deploy at a higher threshold of around 16mph because the belt should provide enough protection up to that speed.
The inflation module will inflate the bag in 25 milliseconds at up to 160mph.
How do airbags inflate so quickly?
The fast inflation of an airbag is caused by a chemical reaction - a gas that explodes rapidly to fill the bag in the blink of an eye.
The most common explosive used in airbags is sodium azide. It’s toxic but poses minimal risks to your health when used in this way. Manufacturers mix it with other compounds to encourage the reaction while reducing your exposure risk.
When the airbag detonates, the plastic covers that usually conceal it are designed to split open without flying off.
Where can you find airbags?
Ask people to picture an airbag, and most would probably imagine it coming from the steering wheel. But there are many other places manufacturers put these clever safety devices you might not know about.
Frontal airbags are located in the steering wheel and on the dashboard on the passenger’s side.
Side airbags inflate from the car doors if the impact sensors detect a side-on collision.
Centre airbags inflate between the two front occupants to prevent head contact during a lateral collision.
Knee airbags are found beneath the driver's steering column and at knee height on the dashboard for passengers.
Seatbelt airbags provide extra protection for a person’s torso during a crash. These are less common than other types.
What does it feel like when an airbag goes off?
Airbags are triggered by a small explosive device, so it can be quite shocking when they go off - but you might not notice it during a crash with so much else going on around you.
You’ll hear a ‘bang’ when the airbag is detonated and may experience ringing in your ears afterwards. Depending on the severity of the crash, it can feel like hitting a soft pillow, or it can hurt and potentially cause injuries like bruising. However, any harm caused by an airbag deployment is generally less severe than the impact of a crash without it.
You may notice talcum powder on your clothes but don’t worry, this is normal - it’s used to lubricate the device while it’s stowed away. Some people also experience chemical and physical burns.
How safe and effective are they?
Airbags are highly effective at reducing injuries and fatalities from car accidents. A study of collisions between 1985 and 1993 found that airbags reduced fatalities by 16% in all crashes and 24% in frontal crashes.
The safety benefits of airbags far outweigh the risks. However, it’s important to note that they are intended to be used with seatbelts. If an airbag detonated at full force when the occupant wasn’t wearing a seatbelt, it could cause serious harm.
Takata airbag recall
While airbags are generally very safe and effective, it’s worth knowing about the Takata recall. Airbags made by this company were fitted to around 60 million vehicles from most manufacturers. They were later found to have a defect that could cause the explosive charge to detonate uncontrolled.
This uncontrolled explosion could cause the metal box around the charge to turn into shrapnel that could seriously injure people.
The UK hasn’t seen any recorded fatalities due to this defect. However, some recalled cars made between 2000 and 2015 haven’t yet been brought in for repair by their owners. When you buy a second-hand car, you should always check for outstanding recalls.
Find out what else to look for when buying a used car.
Airbags and young children
The rear seats are the safest place for children because they’re not at risk from frontal airbags.
You should never put a rear-facing child seat in the front seat of a car with an active airbag because if it deploys, it can injure the child’s head. Most cars have an off switch for the front passenger airbag.
Front-facing child seats can go on the front passenger seat, but you should push the seat as far back as possible. Your vehicle handbook will have information on how to do this.
Should you service your airbags?
There’s no need to service your airbags - they should last the vehicle's lifetime as long as they aren’t damaged.
It was initially thought they had a shelf life of around 10 years, but the Society of Motor Manufacturers and Traders changed their advice on the lifespan in 2010 because airbags had stood the test of time.
You only need to check your airbags when the warning light appears on the dashboard.
Can I get airbags checked in a normal service?
Airbags aren’t usually checked during a car service. If your airbag warning light has come on or you have other concerns, you should book an appointment with a mechanic.
Can I remove airbags myself or switch them off?
Airbags are a valuable safety feature that has saved many lives. You should only remove or switch them off if they pose a threat to vulnerable passengers, such as a child in a rear-facing child seat at the front of the car. For this exact reason, many modern vehicles have a switch that allows you to disable the front passenger airbag.
How to disable the passenger airbag
You may need to turn off the front passenger airbag when travelling with a rear-facing child seat. The method varies between different makes and models, and not all cars have the option to deactivate the airbag in the first place, especially older models.
Usually, you can disable the airbag using a switch near the side of the dashboard or in the glove compartment. The switch has two positions: on (which allows the airbag to activate during a collision) and off (the airbag won’t deploy).
You will usually get confirmation of the airbag’s status via an illuminated dashboard light.
Some vehicles may require you to insert a key to switch the airbag off. Others may require a trip to a garage for deactivation.
The table below explains the deactivation method for different car makes.
| Make | Method |
|---|---|
| Ford | The deactivation lock is in the glove box in some models and on the end of the instrument panel by the passenger door in others. Insert your car key into the deactivation lock, which is clearly labelled, and turn it until the white mark points to the ‘off’ position. When you turn on the ignition, you should see the airbag deactivation warning symbol. |
| BMW | You can deactivate the front and side passenger airbags using your car key. The switch is on the outer side of the dashboard. Insert the key, press it if necessary, and turn it to the ‘off’ position until it stops. Remove the key from the limit position. |
| Renault | The airbag lock is on the outer side of the dashboard. With the vehicle stopped and the ignition off, push and turn the lock to the ‘off’ position. Turn the ignition on and check the warning light on the display panel near the rear-view mirror. It should be lit up. |
| Nissan | The switch is in the glove box. Push and turn it to the ‘off’ position. Then, switch the ignition on and check the passenger airbag light, which should be illuminated. |
Check your vehicle handbook if you’re not sure how to deactivate the passenger airbag in your car.
Can you replace an airbag?
Yes, airbags can be replaced - but this should be done by a trained professional, and you must never use second-hand airbag parts.
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Written by Ellie
Ellie is FixMyCar's Content Writer. She has over three years of experience writing about cars and regularly collaborates with automotive experts to provide trustworthy advice for drivers that is easy understand. Her work has been featured in Yahoo! Finance, iNews, The Daily Express and The Sun. She has a BA in English literature and an MA in creative writing from Durham University. Outside of work, Ellie follows F1 and eagerly awaits Ferrari's next era of dominance in the sport. She drives a Suzuki Swift.