WHAT YOU 

NEED TO KNOW 

ABOUT 

AIR BAGS 
WHAT YOU


NEED TO KNOW


ABOUT AIR BAGS


I f you are among the millions of 

Americans who will soon purchase, 

lease or rent a motor vehicle, it 

will be equipped with one or more 

air bags. Air bags are called supplemental 

restraints because they are designed to work 

best in combination with safety belts. You 

should always wear your safety belt whether 

or not your car has an air bag. All new 

passenger cars, light trucks and vans are 

equipped with both driver and passenger front 

air bags. (While many new vehicles are being 

equipped with side air bags, this brochure 

focuses mainly on front air bags. See the 

“New Technology” section for information 

on new air bag technologies.) 

2

The Air Bag
 System for


Frontal Crashes


T he air bag system consists 

of three basic parts — 

an air bag module, crash 

sensors and a diagnostic unit. 

Some systems may also have an 

on/off switch, which allows the 

air bag to be deactivated. 

1 The AIR BAG MODULE 

contains both an inflator unit and 

the lightweight fabric air bag. The 

driver air bag module is located in 

the steering wheel hub, and the passenger air 

bag module is located in the instrument 

panel. When fully inflated, the driver air bag 

is approximately the diameter of a large beach 

ball. The passenger air bag can be two to three 

times larger since the distance between the 

right-front passenger and the instrument panel 

is much greater than the distance between the 

driver and the steering wheel. 

continued next page


3

2 The CRASH SENSORS are 

located either in the front of the 

vehicle and/or in the passenger 

compartment. Vehicles can have one 

or more crash sensors. The sensors are typically 

activated by forces generated in significant 

frontal or near-frontal crashes. Sensors measure 

deceleration, which is the rate at which the 

vehicle slows down. Because of this, the vehicle 

speed at which the sensors activate the air bag 

varies with the nature of the crash. Air bags are 

not designed to activate during sudden braking 

or while driving on rough or uneven pavement. 

In fact, the maximum deceleration generated in 

the severest braking is only a small fraction of 

that necessary to activate the air bag system. 

3 The DIAGNOSTIC UNIT 

monitors the readiness of the air bag 

system. The unit is activated when 

the vehicle’s ignition is turned on. 

If the unit identifies a problem, a warning 

light alerts the driver to take the vehicle to an 

authorized service department for examination 

of the air bag system. Most diagnostic 

units contain a device, which stores enough 

electrical energy to deploy the air bag if the 

vehicle’s battery is destroyed very early in a 

crash sequence. 

4 Some vehicles without rear 

seats, such as pick up trucks and 

convertibles, or with rear seats too 

small to accommodate rear-facing 

child restraints, have manual ON/OFF switches 

for the passenger air bag installed at the factory. 

ON/OFF switches for driver or passenger air 

bags may also be installed by qualified service 

personnel at the request of owners who meet 

government-specified criteria and who receive 

government permission. (For more details, 

see the section “Deactivation.”) 

4

5 

ir bags are typically designed to 

deploy in frontal and near-frontal 

collisions, which are comparable 

to hitting a solid barrier at 

approximately 8 to 14 miles per hour (mph). 

Roughly speaking, a 14 mph barrier collision 

is equivalent to striking a parked car of similar 

size across the full front of each vehicle at about 

28 mph. ked car absorbs 

some of the energy of the crash, and is pushed 

by the striking vehicle. nlike crash tests into 

barriers, real-world crashes typically occur at 

angles, and the crash forces usually are not 

evenly distributed across the front of the 

vehicle. , the relative speed 

between a striking and struck vehicle required 

to deploy the air bag in a real-world crash 

can be much higher than an equivalent 

barrier crash. 

Because air bag sensors measure deceleration, 

vehicle speed and damage are not good 

indicators of whether or not an air bag 

should have deployed. ccasionally, air bags 

can deploy due to the vehicle’s undercarriage 

violently striking a low object protruding 

above the roadway surface. espite the lack 

of visible front-end damage, high deceleration 

forces may occur in this type of crash, resulting 

in the deployment of the air bag. 

A 

When Do Air 

Bags Deploy? 

? ? 

This is because the par

U

Consequently

O

D
6

Angle of Frontal Impact

30 ̊ 30 ̊

Most air bags are designed to automatically

deploy in the event of a vehicle fire when

temperatures reach 300 to 400 degrees

Fahrenheit. e helps to ensure

that such temperatures do not cause an explosion

of the inflator unit within the air bag module.

Front air bags are not designed to deploy in

side impact, rear impact or rollover crashes.

Since air bags deploy only once and deflate

quickly after the initial impact, they will 

not be beneficial during a subsequent collision.

Safety belts help reduce the risk of injury in

many types of crashes. operly

position occupants to maximize the air bag’s

benefits and they help restrain occupants

during the initial and any following 

collisions. o, it is extremely important 

that safety belts always be worn, even in 

air bag-equipped vehicles. 

Approximately 1/20th sec. 

This safety featur

They help to pr

S
When


a Collision


Occurs


W hen a crash occurs, the vehicle 

rapidly decelerates while its 

structure absorbs the majority 

of the crash forces. Unbelted 

occupants continue to move forward at the 

vehicle’s original speed until the vehicle’s 

interior (the steering wheel, instrument panel, 

windshield, etc.) stops their movement. Belted 

occupants come to a more gradual stop by being 

secured to the vehicle’s structure. In severe 

crashes, even properly belted occupants may 

come into contact with the vehicle’s interior. 

Air bags supplement the safety belt by reducing 

the chance that the occupant’s head and upper 

body will strike some part of the vehicle’s 

interior. They also help reduce the risk of 

serious injury by distributing crash forces 

more evenly across the occupant’s body. 

continued next page


Less than 1 sec. 

7

When 

a Collision 

Occurs (cont.) 

When there is a moderate


to severe frontal crash that


requires the frontal air bag


to deploy, a signal is sent to


the inflator unit within the


air bag module. An igniter


starts a reaction, which


produces a gas to fill the air


bag, making the air bag


deploy through the module


cover. Some air bag technologies use 


nitrogen gas to fill the air bag while others 


may use argon gas. The gases used to fill air


bags are harmless. 


From the onset of the crash, the entire


deployment and inflation process takes only


about 1/20th of a second, faster than the blink


of an eye. Because a vehicle changes speed so


fast in a crash, air bags must inflate rapidly if


they are to help reduce the risk of the occupant


hitting the vehicle’s interior.


8

What Happens


After a


Deployment?


O nce an air bag deploys, deflation 

begins immediately as the gas 

escapes through vents in the 

fabric. Deployment is frequently 

accompanied by the release of dust-like 

particles in the vehicle’s interior. Most of this 

dust consists of cornstarch or talcum powder, 

which are used to lubricate the air bag during 

deployment. Small amounts of sodium 

hydroxide may initially be present. This 

chemical can cause minor irritation to the eyes 

and/or open wounds; however, with exposure 

to air, it quickly turns into sodium bicarbonate 

(common baking soda). Depending on the 

type of air bag system, potassium chloride 

(a table salt substitute) may also be present. 

continued next page 

9

What Happens

After a 

Deployment? (cont.) 

For most people, the only effect the dust may 

produce is some minor irritation of the throat 

and eyes. Generally, minor irritations only 

occur when the occupant remains in the vehicle 

for many minutes with the windows closed and 

no ventilation. However, some people with 

asthma may develop an asthmatic attack from 

inhaling the dust. With the onset of symptoms, 

asthmatics should treat themselves as advised 

by their doctor, then immediately seek 

medical treatment. 

Once deployed, the air bag cannot be reused 

and should be replaced by an authorized service 

department. Because the air bags only deploy 

once, do not drive the vehicle until the air bags 

have been replaced. 

10

Air Bag


Contact Injuries


A ir bags must inflate very rapidly to be 

effective, and therefore come out of the 

steering wheel hub or instrument panel 

with considerable force, generally at a 

speed over 100 mph. Because of this initial force,


contact with a deploying air bag may cause injury.


These air bag contact injuries, when they occur, 


are typically very minor abrasions or burns. 


More serious injuries are rare; however, serious or


even fatal injuries can occur when someone is 


very close to, or in direct contact with an air bag


module when the air bag deploys. Such injuries


may be sustained by unconscious drivers who are


slumped over the steering wheel, unrestrained or


improperly restrained occupants who slide forward


in the seat during pre-crash braking, and even


properly restrained drivers who sit very close to the


steering wheel. Never attach objects to an air bag


module or place loose objects on or near an air bag


module, since they can be propelled with great


force by a deploying air bag, potentially causing


serious injuries.


An unrestrained or improperly restrained occupant


can be seriously injured or killed by a deploying 


air bag. The National Highway Traffic Safety


Administration (NHTSA) recommends drivers sit


with at least 10 inches between the center of their


breastbone and the center of the steering wheel.


Children 12 and under should always 


ride properly restrained in a rear 


seat. Never put a rear-facing infant


restraint in the front seat of a


vehicle with a front passenger air


bag. A rear-facing infant restraint


places an infant’s head close to the


air bag module, which can cause


severe head injuries or death if the 


air bag deploys. (See the next


section, “Air Bags, Safety Belts 


and Child Safety Seats.”) 11

Air Bags, Safety


Belts and Child 


Safety Seats


A ll front seat occupants must be 

correctly positioned in order to 

optimize the benefits of a deploying 

air bag. The proper use of safety 

belts is an important part of correct positioning. 

Unbelted or improperly belted occupants can 

come into contact with the air bag module 

during pre-crash braking. Being near or against 

an air bag module when it deploys can result in 

serious or fatal injury. 

Safety belts should always be worn with the 

lap belt low and snug across the hips and the 

shoulder belt across the chest. Shoulder belts 

should never be placed under the arm or behind 

the back. Front seat drivers and passengers 

should sit upright against the back of the seat. 

Passengers should adjust the seat as rearward as 

practical. Drivers should adjust the seat such 

that they position themselves away from the air 

bag module, while maintaining the ability to 

safely operate all vehicle controls. Moving the 

seat rearward, slightly reclining the seat back 

and/or tilting the adjustable steering wheel 

downward can change the driving position. 

Remember, NHTSA recommends there must be 

at least 10 inches distance between the steering 

wheel hub, where the air bag module is located, 

and the driver’s breastbone. 

12

Children are safest when properly restrained in a 

rear seat, whether the vehicle has an air bag or 

not. Infants should be restrained in rear-facing 

restraints until they reach 20 pounds and are at 

least one year of age. Never put a rear-facing 

infant restraint in the front seat of a vehicle with 

a front passenger air bag. The back of the rearfacing infant restraint rests too close to the air 

bag module, creating the potential for serious 

or fatal injuries from a deploying air bag. 

After children reach 20 pounds and one year 

of age, they can be moved into forward-facing 

child restraints. When children exceed 

40 pounds in weight, they should ride in 

belt-positioning booster seats until the vehicle 

safety belt fits properly (see page 12), which 

as a rule of thumb may be until they are at least 

8 years old, unless they are 4’9” tall. Most 

booster seats accommodate children up to 

80 lbs. Always follow the child restraint and 

vehicle manufacturers’ instructions for proper 

use and installation of child restraints. 

Pregnant women should always wear their 

safety belts. They should sit as far back as 

possible from the air bag with the lap portion 

of the belt correctly positioned over the hips 

(not the stomach) and the shoulder portion 

across the chest. 

13

Deactivation


T he vast majority of people can benefit 

greatly from an air bag, and can 

reduce any risk of air bag contact 

injuries just by buckling up on every 

trip and properly restraining children 12 and 

under in a rear seat. Almost all air bag-related 

deaths have involved unrestrained or improperly 

restrained occupants. Since the combination of 

an air bag and a safety belt reduces the risk of 

serious head injury by 83 percent, consumers are 

urged to carefully consider their needs prior to 

installing an on/off switch. 

However, NHTSA will allow some consumers to 

install an on/off switch to disconnect a driver or 

passenger air bag, but only if they fall into one 

of the following categories: 

● 	Those who have a medical condition that 

places them at specific risk. 

● 	Those who cannot adjust their driver’s 

position to keep at least 10 inches from the 

steering wheel. 

● 	Those who cannot avoid situations that 

require a child 12 or under to ride in the 

front seat. 

14

Automakers are not required to make the 

switches available, nor are dealers required to 

install them. Due to vehicle design and other 

considerations, switches may not be available 

for all vehicle makes and models. 

Even those who may be eligible for the on/off 

switch may be able to safely accommodate the 

air bag by going through the following steps: 

● 	 Discuss your medical condition with your 

physician and together decide whether an air 

bag switch is appropriate for you. 

● 	 To get more space between you and the 

steering wheel, move the seat farther back or 

adjust the angle of the seatback. If you are 

shopping for a new car, sit in several models 

or consider a power seat option to enable 

you to sit comfortably farther away from the 

steering wheel. 

● 	 Children are safer in a rear seating position, 

with or without an air bag. In more than 

70% of the cases where a child in the front 

seat was killed in a crash, there was a vacant 

rear seating position available. If you are 

looking for a new car, select one with 

enough rear seating positions to 

accommodate the maximum number of 

children you expect to transport. 

If you still think you need an on/off switch, 

contact your vehicle manufacturer to find out 

if a switch is available for your vehicle. You will 

then need to obtain permission to install the 

switch from NHTSA by obtaining a request 

form (1-888-327-4236 or www.nhtsa.dot.gov). 

15

New


Technologies


Advanced Air Bag Technologies 

Many advanced air bag technologies are being 

developed to tailor air bag deployment to the 

severity of the crash, the size and posture of the 

vehicle occupant, belt usage and how close that 

person is to the air bag module. Many of these 

systems will use multi-stage inflators that deploy 

less forcefully in stages in moderate crashes than 

in very severe crashes. Occupant sensing devices 

let the air bag diagnostic unit know if someone 

is occupying a seat in front of an air bag, 

whether the person is an adult or a child, 

whether a seat belt or child restraint is being 

used and whether the person is forward in the 

seat and close to the air bag module. Based on 

this information and crash severity information, 

the air bag is deployed at either a high force 

level, a less forceful level or not at all. 

For evaluating advanced air bag systems, 

laboratory tests utilizing a family of crash test 

dummies will be required. In addition to tests 

using a dummy representing an average adult 

male, future air bag systems will be tested 

with a small adult female dummy and dummies 

representing one, three and six year old children. 

These new NHTSA requirements are being 

phased in over the next several years with some 

vehicles already in production. 

However, even with advanced air bag 

technologies, children ages 12 and under 

should always ride in a rear seating position 

in an appropriate restraint system. 

16

Side and Rollover Air Bags 

Many new vehicles are also equipped with side 

air bags. While there are several types of side air 

bags, all are designed to reduce the risk of injury 

in moderate to severe side impact crashes. These 

air bags are generally located in the outboard 

edge of the seat back, in the door or in the roof 

rail above the door. 

Seat and door-mounted air bags all provide 

upper body protection. Some also extend 

upwards to provide head protection. Two types 

of side air bags, known as inflatable tubular 

structures and inflatable curtains, are specifically 

designed to reduce the risk of head injury 

and/or help keep the head and upper body 

inside the vehicle. A few vehicles are now 

being equipped with a different type of 

inflatable curtain designed to help reduce 

injury and ejection from the vehicle in rollover 

crashes. Read your owner’s manual for specific 

information about the air bags in your vehicle. 

Unlike front air bags, side air bags are neither 

required nor regulated by NHTSA. At 

NHTSA’s request, a Technical Working Group 

representing automakers, air bag suppliers and 

independent safety organizations has developed 

comprehensive uniform test procedures for side 

air bags. The test procedures will help air bag 

designers to evaluate the risk of inflation-related 

continued next page 

17

New


Technologies (cont.) 

injuries to out-of-position occupants, 

particularly children and small adults, 

and to design systems that minimize these 

risks. All vehicle manufacturers have agreed 

to utilize these tests when designing future 

side air bag systems. 

While side air bags are smaller than front 

air bags, they must deploy very rapidly. 

Close proximity of a child’s head, neck or 

chest to a side air bag may cause serious injury. 

Therefore, it is important never to lean up 

against or rest against a side air bag. Seat belts 

(or child restraints as appropriate) should always 

be worn to avoid possible injury by keeping 

enough distance between the occupant and 

the side air bag module. 

If you transport children and are thinking about 

buying a car with side air bags in rear seating 

positions, check the vehicle and child restraint 

manufacturers’ recommendations for child 

restraint use in that vehicle. 

18

Summary


Always Wear Your Safety Belt. 

Restrain All Children in a Rear Seat. 

A ir bags, while they save 

lives, are but one of many 

important vehicle safety 

systems. It is critical that occupants 

always properly wear their safety 

belts and remember: 

● Never put a rear-facing infant restraint in 

the front seat of a vehicle with a front 

passenger air bag. 

● Children 12 and under should be properly 

restrained in a rear seat. 

● Drivers should sit with at least 10 inches 

between the center of their breastbone and 

the center of the steering wheel. 

● Front air bags are designed to deploy only 

in moderate to severe frontal or near-frontal 

collisions, and do not reduce the risk of 

injury in rear, side or rollover crashes. 

Safety belts help reduce injury risk in 

many types of crashes. 

● Air bags deploy only once. Safety belts help 

restrain occupants during the initial and 

any following collisions, if the vehicle strikes 

more than one object. 

● Safety belts help keep front seat occupants 

in position to maximize an air bag’s 

effectiveness. Remember, very close or 

direct contact with an air bag module 

during deployment can cause serious 

or even fatal injury. 

19

1110 N. Glebe Road, Suite 1020 

Arlington, VA 22201 

(703) 243-7501 

www.actsinc.org 

November 2002 

1-888-DASH-2-DOT 

Distributed in cooperation with the National 

Highway Traffic Safety Administration.