When either type of inflator deploys, the gas that is produced always contains byproducts of the combustion process. These byproducts can include dangerous gases as benzene and toluene, as well as particulates that appear to be smoke. This is one reason why many people involved in an accident where the airbags deployed report seeing smoke in the passenger compartment. These byproducts can cause significant breathing difficulties, particularly in those people who already suffer from asthma or other respiratory problems.

Through most of the 1990s, the cars produced by the car companies used a “one size fits all” inflator in their airbag systems. That meant that once your airbag sensors sent the deployment signal, the airbag would deploy with the same force regardless of the accident circumstances. So, you got the same airbag force in an 8 mph fender-bender as a highway-speed head-on collision. It didn’t matter whether you were a short woman or a big and tall man – it was always the same. However, dual stage inflators were feasible during that time frame; they would adjust the force of the deployment based on the severity of the accident. Most people don’t realize that such dual stage airbags were being sold by General Motors in the mid-1970s at its Oldsmobile, Buick and Cadillac dealers.

Since the late 1990s, car companies have returned to dual stage inflator technology, and are now using multi-stage technology. These inflators adjust the force of the deployment depending on such things as crash severity, seat belt use, seat position and occupant size.  Many of these airbag systems use advanced computer systems to adjust the inflator force; unfortunately, as with many other computer-based systems, they sometimes fail with devastating results.  Sometimes the airbag inflator deploys at full power when it should not have deployed at all.  At other times, the airbag inflator does not deploy at all when it should have, depriving the person of the safety benefits of their airbag.

With the complexity of today’s airbag systems, you need an experienced airbag attorney, preferably with an airbag engineering background, to determine whether your airbag system worked as intended during your accident.

The earlier systems recorded information about the status of the airbag system, including any fault codes that were present, or that had been present, and the length of time the warning lamp had been on. Some of these systems had their reliability questioned, as the data download sometimes did not match what had been physically observed in the car.

By the mid to late 1990s, GM had the most systems in cars driven by consumers that could be downloaded using commercially available equipment. That meant that accident reconstruction experts, airbag experts, and police agencies could perform their own downloads of the information contained in the black box. The availability of such equipment was important, as the information is stored in the black box in hexadecimal format requiring conversion to understand it. It still takes expertise to interpret those downloads, and not all the information stored in the black box is converted with that type of equipment. These systems typically recorded the crash severity (change in velocity over time), airbag system status, problem history and, importantly, seat belt usage.

By the late 1990s, these black boxes recorded not only the vehicle conditions at the time of the crash, but also five seconds of pre-crash data. That data includes vehicle speed, vehicle braking, engine RPM, and throttle position. Some of this data can be recorded not only for actual crashes, but also certain near-crashes where the computer algorithm experienced enough acceleration to be enabled.

By the mid 2000s, the data captured by these black boxes had grown significantly. They can record the seat position, inflator staging, what specific parameter caused airbag deployment, whether the passenger airbag was suppressed, and many other things. Some even include the air temperature at the time of the accident. Some of these newer systems are automatically tied into crash response notification if the airbag deploys, such as through uploading to On-Star.

The ownership of the data within the black box is a developing field of the law. Generally, most states treat the owner of the vehicle or the lessee as the owner of the data generated when they owned or leased the vehicle. They would then presumably have some privacy protections. However, some “fine print” in the manuals of certain manufacturers contains exceptions from these privacy protections. I expect that these exceptions will be subject to litigation in the future. The ownership of the data also surfaces in certain criminal cases involving DUI, vehicular homicide or manslaughter and other cases. Criminal courts have often required a search warrant before a police agency can download such data.

The federal regulations relating to black box data are not very comprehensive. One federal agency, the U.S. National Highway Traffic Safety Administration (NHTSA) has published rules on this topic. Incredibly, those regulations do not require a manufacturer to have a black box for their airbag system at all. However, if a manufacturer chooses do install a black box, those regulations standardize what data must be collected and how it must be accessible.

Some airbags are designed to have holes in them. These are called vent holes, because their purpose is to release or “vent” the gas that is inside the airbag. As the gas exits the vent holes, the airbag compresses, gradually slowing down your body during a crash. These vent holes are usually round, and can have a diameter of between about ¾ inch and 3 inches. The smaller vent holes are often used in driver airbags, with the larger vent holes used almost exclusively in passenger air bags. When you look at them, the circular shape should be fairly obvious. However, if the fabric around the edge of the vent is not reinforced, the pressure within the airbag during the crash can make the round hole more square in shape by slight tearing of the fabric. This can be normal, if they were designed to tear. In almost all cases, vent holes in a driver air bag should face to the front, away from you. Vent holes in a passenger air bag are generally on the sides of the airbag, and not in the portion of the fabric that you normally touch.

A few vehicles used “petal vents” which are semi-circular slits in a driver airbag. The intent is that these vents open up like a flap when the airbag is pressurized. Some believe that these vents are not nearly as efficient as traditional vent holes, and can be a sign of an inflator that over-pressurizes the airbag.

Holes in your airbag that are lengthy or irregular can be signs that your airbag tore during deployment. We have seen some instances where the fabric “catches” on a piece of the surrounding frame or cover. If this happens, your airbag did not perform as it should have, and you may not have been fully protected during your accident. In a few cases, large scale ripping of the airbag fabric (or its tethers) is caused by airbag inflators that are overly aggressive: their forcefulness simply rips the fabric apart during the deployment process. These are clearly defective.

In some other instances, you can have either a circular hole or an irregular hole in the fabric closest to the driver or passenger. These can be caused by defects in the airbag inflator that cause it to break apart. Loose pieces from such a defect can then be sent flying like shrapnel right through the bag. These same pieces can cause devastating injuries to a driver or passenger in their path.

A car company or supplier who produces defective airbags or airbag inflators should accept responsibility for their defect; if not, you should speak with an air bag lawyer knowledgeable about such issues.

The differences among airbags extend to various characteristics. First, the inflators that generate the gas that fills the airbag can be of different types. Some used solid chemicals such as sodium azide to produce nitrogen gas. Others use stored gas; for example, some use a mixture of helium and argon. Some inflators deploy at the same force level, regardless of the accident severity. Others adjust the deployment forces based on the size and position of the passenger or based on the severity of the crash.

The fabric airbags themselves can also vary widely. Some are nylon, some are polyester. Some have vent holes, others don’t. Some are coated to control the amount of gas exhausted from the bag when the person pushes against it during a crash. Some reach so far toward the passenger that they can slam into their face at hundreds of miles per hour, even if the passenger has not yet moved in response to crash forces. Some are tethered to reduce this risk.

Airbag crash sensors can also vary widely by cars. In the early 1990s, most manufacturers used crash sensors mounted in the front of the car. By the mid 1990s, some of these manufacturers eliminated these front safety sensors, saving millions of dollars in the process. By the late 1990s and early 2000s, some of these manufacturers shifted back to systems that included front airbag crash sensors. Even so, our research and investigation has revealed that similar cars sold under different brand names fail to include such front crash sensors on some models, even though they are present in other models.

Sensing systems that fail to include front crush zone sensors can have many problems. They often have difficulty sensing real-world accidents quickly enough, which can result in late deployments that cause serious personal injuries or even a wrongful death from the airbag deployment. They can also fail to deploy the airbags in crashes involving a tree or utility pole. Some manufacturers made their remaining sensors too sensitive, in an attempt to create a cheap fix for these problems. This has resulted in numerous deployments where airbags were not intended to deploy, including rock impacts to an undercarriage and very minor crashes.

In short, there are significant differences among various airbag designs. There are also significant differences in the ways different car companies engineer their airbags, with some companies using shortcuts to reduce the amount of money they spend to engineer their airbags. Those airbags can be much more dangerous than other airbags.

AIR BAG DEPLOYMENT THRESHOLDS

Conventional air bags are generally designed to deploy in certain frontal crashes above the thresholds selected by the manufacturer.  Unfortunately, the consumer often cannot determine the thresholds for their car, as they vary widely between manufacturers, and even vary among different models from the same manufacturer.  However, there are some general guidelines that are helpful for consumers.

Although there were some variations, most frontal air bags from the 1990s were designed to deploy in crashes above a threshold level of 14 mph into a solid concrete barrier.  At the same time, most air bag systems were also designed to never deploy in crashes below 8 mph into a solid concrete barrier.  Between these two speeds, the air bags may or may not deploy, depending on the specifics of the accident and vehicle.

Airbag Deployment Threshold

The bottom line is this: airbag should always deploy in every crash where they are likely to prevent serious personal injury or a wrongful death.  If your crash severity exceeds the car company’s thresholds, and yet your air bags did not deploy, you may well have a defect in your vehicle’s air bag system.

CRASHES WHERE THE AIR BAG SHOULD DEPLOY

Your air bags should deploy in every crash where they will help prevent your injuries.  This means that your air bag should deploy in those crashes where you would otherwise suffer injuries of the type that the air bag is designed to prevent: head, neck, and chest injuries.  For example, your frontal air bag should deploy in an accident where your head would otherwise be injured from hitting your steering wheel.  Shown here is an example of an accident vehicle in which the air bags should have deployed.

Ford Airbag Failed to Deploy

Although frontal air bags are generally not designed to deploy in side impacts or rollovers, in some cases they should deploy in those kinds of crashes.  That is because some side impacts or rollovers also cause front-to-back deceleration that causes you to move forward inside your vehicle.  One example would be if you were driving at highway speed and were hit on the side of your car: in addition to crushing in the side of the car, your car would also slow down its forward motion rapidly, which could be enough to deploy your frontal air bags.  Similarly, frontal air bags should generally not deploy in rear impacts; however, if you are hit from behind and pushed into a car in front of you, that second impact to your car’s front end may justify deployment of your air bags.

For side impact air bags, they should generally deploy on the side of the car experiencing the side impact.  Similarly, rollover “curtain” air bags should deploy when the vehicle experiences a rollover, to help prevent head and neck injuries and to reduce the risk of being ejected through an open or shattered window.
     
Examples of crashes where air bag deployment would be expected include moderate to severe crashes involving your front bumper or the front corners of your vehicle, frontal impacts to a utility or telephone pole, and under-ride impacts where the front of your car goes under the side or back of a truck.

CRASHES WHERE THE AIR BAG SHOULD NOT DEPLOY

Your air bags should not deploy in those accidents where they will not prevent your injuries.  After all, air bags can deploy at speeds of more than 200 mph, and you should not be exposed to those kinds of forces if it won’t help you.  Thus, your frontal air bags should not deploy in side impacts, rear impacts and rollovers where there is no significant deceleration from front to back.  Other examples of crashes where your frontal air bags should not generally deploy include:

• Minor frontal crashes
• Most impacts to the undercarriage of the vehicle, such as when crossing a railroad, unless they would result in serious personal injury
• Impacts with animals such as deer or dogs
• Impacts with street curbs or parking blocks
• Driving on rough roads, including those with large potholes, gravel or bumps

Of course, your air bags should never deploy when your vehicle is not in an accident.  Although this seems obvious, there are actually many cases where this has occurred, often due to poor design of the air bag system software, or due to electrical issues with the air bag system.

WHY YOUR AIR BAG DID NOT DEPLOY

There are several reasons why your air bag may not have deployed during a crash.  The first reason is that perhaps your crash is not the type of accident where air bag deployment would be helpful.  For frontal air bags, this includes many, but not all, side impacts, rear impacts and rollovers.  This category also includes minor accidents in which the driver and front passenger (if there was one) did not suffer any significant injuries requiring medical treatment.

The second reason is that there could be a defect that prevented the crash sensors from detecting the crash properly.  Our investigation and analysis of air bag systems in hundreds and hundreds of crashes has revealed numerous causes that fall within this category.  In some cases, the air bag deployment threshold is simply not set appropriately, often due to inadequate testing.  In other cases, a flaw in the software of the air bag control module has caused it to ignore the data from one of the crash sensors.  In still other cases, there are simply too few sensors to properly detect real-world crashes; this often results from overly zealous cost-reduction efforts by car companies that are trying to improve their finances.  In a few cases, quality control efforts have failed to prevent defective sensors or air bag control modules from reaching the public.

2002 Buick Century: Fatal Non-Deployment

The third reason is that there could be a defect that prevented the deployment signal from reaching the air bag modules and deploying them.  Here, the problem usually lies with the electrical components and wiring between the crash sensors, control module and the air bag modules.  The most frequent defect in this category that we see is when the driver air bag fails to deploy, but the passenger air bag does deploy.  In many cases, this is due to a defective clockspring located in the steering column.  Millions of defective clocksprings have been recalled, generally due to poor quality control at either the supplier’s production plant or the car company’s assembly plant.

Airbag Clockspring

Ford Airbag Sensor Cut Wire

The fourth reason is that there could be a defect that prevented the actual air bag modules from deploying correctly.  In a few cases, the crash sensors and air bag control modules have commanded deployment of the air bags, but the air bags failed to respond.  This is almost always due to defects within the air bag modules themselves, usually due to poor quality control.

Although each vehicle and each accident is different, I can help you determine whether the air bags in your car should have deployed in your accident.  As an air bag attorney, as a former air bag engineer for General Motors, and as a court-recognized air bag expert witness, I have over 20 years of experience in analyzing air bag system performance.  If your air bag system is defective and you have a case, I would be honored to pursue justice for you.

Tethers also have other advantages. They help position the airbag properly during the deployment sequence so that it does not slam a passenger in the face, and can provide maximum protection during a crash. They also help ensure a more consistent deployment, helping reduce the effects of manufacturing inconsistencies.

Some manufacturers use tethers in many of their driver airbags.

Airbag Tether

Unfortunately, some of these car companies (including Chrysler and Honda/Acura) did not implement tethers until after consumers suffered numerous facial injuries from their initial airbags that did not include tethers. Other manufacturers fail to use tethers in passenger airbags even though even the most basic review of crash testing shows they strike the passenger in the face during deployment and before they achieve their fully inflated shape.  In our airbag lawsuits, we have also uncovered some airbags that have a very poorly designed tether that still allows people to be blinded by the airbag.

A design standard for the industry to limit the risk of eye injuries was published in the 1970s. That standard specified a maximum speed of an airbag if it contacts a passenger in the eyes. Incredibly, some manufacturers still do not conduct testing to measure the speed of their inflating airbag, even when it is clear that the airbag can strike the passenger in the eyes.

Government studies have confirmed the benefits of tethers in laboratory tests, and technical papers published in the industry have proven that tethers reduce eye injuries during accidents where the airbags deploy.

Our testing in this area has documented that some untethered airbags carry a significant risk of causing blindness and eye injuries. In fact, our data reveals that some of passenger airbags deploy at speeds above 300 mph! Can you imagine having an airbag hit you in the eyes at 300 mph? Now you know why tethers should be used inside YOUR airbag.

How can you tell if your airbag has tethers?  Unfortunately, most manufacturers do not tell consumers whether the airbags in their cars are tethered.  Often, people find out their airbag lacked this safety feature only after they were injured by the airbag after it deployed in a wreck.  An experienced airbag lawyer knows what to look for to determine whether tethers were used in your airbag, and whether the tethers worked appropriately.

Driver airbags are generally pancake-shaped. Their diameter is usually slightly larger than the steering wheel. Passenger airbags are irregularly shaped, and are designed to fit in the area between the instrument panel (dash), windshield, and the passenger. Thus, passenger airbags are much larger than driver airbag, sometimes up to four times as large.

Airbags are generally constructed of a tightly woven fabric, usually nylon or polyester. The fabrics themselves are characterized by various engineering parameters, including weave, weave count, denier and others. These specify the thickness or density of the material, and the tightness of the weave.

One extremely important characteristic of frontal airbags is whether they include tethers to maximize their safety. Tethers are internal straps inside the airbag that help prevent high speed bag slap injuries to a person’s face. Such bag slap injuries often include eye injury and blindness. Some manufacturers failed to include tethers in their airbags, saving themselves millions of dollars, but putting their customers at risk of serious and permanent injuries. Tethers will be explored in detail in another post.

Sometimes the fabric is coated on the inside to reduce the amount of gas that leaks out through the permeable fabric and the seams. This is often true of driver airbags that deploy from the steering wheel and rollover airbags that deploy from the roof. A rollover airbag must stay inflated longer because rollover crashes last much longer than typical head-on collisions, and using a coated airbag helps the airbag stay inflated.

Side airbags come in a variety of sizes. Some side impact airbags are mounted to the seat and deploy between a passenger and the door to protect the chest and pelvis. Better side impact airbags also protect the passenger’s head. This can be accomplished by a combination torso/head bag deploying from the seat or door, or by using a side curtain airbag that deploys downward from the roof and extends along the side of a vehicle. The best curtain airbags are also triggered during rollover crashes, as well as side impacts. Such rollover airbags have been installed in vehicles sold in the United States since the 2002 model year. However, some manufacturers failed to install them until much later, unnecessarily exposing their customers to the risk of significant injuries during a rollover crash.

Crash sensors for side airbags are usually installed inside the bottom of the “B-pillar,” the post behind the front door that helps hold up the roof. In some vehicles, these crash sensors are inside the front door or near the back seat area.

Your car, truck, van or SUV usually has at least one crash sensor on each side of the vehicle. During a side impact crash, the side airbag sensor should detect the sideways (lateral) deceleration and send an electrical signal to the airbags to begin inflating.

Side airbags are most commonly installed inside your seat, attached to the upper part of the seat frame nearest the door. In a few vehicles, the side airbags are installed inside your door, beneath the plastic trim cover. These side airbags are designed to provide a protective cushion between you and the side of your car.

3 Types of Side Airbags

• “Torso” airbag – Rectangular in shape, it protects only the torso or upper body and is often less than 18 inches tall when fully inflated. These airbags usually provide very little protection to your head and neck.
• “Head and torso” airbag – Taller than a regular torso bag, this type of airbag protects you better in a vehicle accident by protecting your head, neck and chest from the side of your car and the vehicle that hit you. This is particularly true when you are hit in the side of your vehicle by a taller vehicle, such as a pickup truck, van or SUV.
• “Curtain” airbag – A curtain airbag deploys downward from the edge of the roof and is intended to cover most of the window so your head and neck are protected, even when you would otherwise move outside the window during the accident.

For maximum protection, curtain airbags are sometimes combined with torso airbags that deploy from the seat or door trim to protect your chest. In many cases, such curtain airbags extend from the front seat toward the back, and can thus also protect back seat passengers.

In prior years, other types of side airbags were sometimes used, but on a much smaller scale. For example, a few cars used a tubular protection system consisting of an airbag shaped like a tube that ran from the front to the back of the door, extending across the window.

These systems need a separate torso airbag to adequately protect your chest. Often, there were significant disadvantages associated with such side airbags that resulted in limited use.

For front airbags, the driver’s airbag is in the center of the steering wheel, and the passenger’s airbag is in the dash in front of the passenger seat. Side airbags are generally in the side of the seat or behind the plastic trim next to the seat. Newer curtain, rollover or canopy airbags are located in the edges of the roof, and deploy down along the side windows.

These modules must contain certain specific safety features to prevent the airbag from causing unnecessary head, neck, chest or other injuries.

2. Airbag Sensors and Diagnostics: The crash sensors are the “brains” of the airbag system, deciding whether and when to deploy the airbags in an automobile accident or collision.

The diagnostic portion of the airbag system is intended to diagnose certain electrical problems within the airbag circuits. These diagnostics evolved into modern “black boxes” that record crash information and go by names such as:

• ECU (Electronic Control Unit)
• SDM (Sensing and Diagnostic Module)
• RCM (Restraints Control Module)
• ORC (Occupant Restraints Controller)
• EDR (Event Data Recorder)

Sensor failures can lead to airbags not deploying during a car accident where they should have protected a consumer. They can also lead to unnecessary deployments that can cause a crash to occur, or can directly injure a consumer.

3. Clockspring: An electrical component in the steering wheel, the clockspring allows electrical current to flow through the wires in the steering column to the driver airbag module mounted in the steering wheel. When this part is defective, it can prevent the driver’s airbag from deploying, even during a high-speed wreck. Millions of these components have been recalled, often due to a poor design, lack of testing, or inadequate quality control.

4. Warning Lamps: These warning lights in your instrument cluster or on your dash should show the electrical status of your airbag system. When you start your car, the warning lamp should flash or stay on for about six seconds while the diagnostic unit checks the system. If your warning lamp comes on while you’re driving, you probably have a defect in your airbag system, which could cause the airbag system to unnecessarily deploy or can prevent deployment in a crash.

5. Passenger Airbag On-Off Switches: In some vehicles, including pickup trucks and cars without a back seat, a key-operated on/off switch is located in the dash. These are typically intended to allow a driver to shut off the passenger airbag when infants or small children do not have an adequate back seat in which to sit and must instead sit in the front seat.

6. Passenger Presence Detection and Occupant Classification Systems: Newer advanced airbags include various methods to determine the presence and size of the front passenger, in order to adjust how forcefully the airbag should deploy.

If there is no passenger, or if an infant or child becomes too close to the dash, these advanced airbags are typically intended to prevent the deployment of the airbag. If the occupant is an adult, such systems can tailor the inflation force to the person’s size or position. A failure in these systems can have deadly consequences.

7. Other Components: Other parts of your car should also be designed to work together with your airbag system during a crash, including deployment doors, trim covers, knee bolsters, steering columns, steering wheels, sun visors, windshields, seats, dash or instrument panels (I/P), and sometimes even the inside rear view mirrors.

In earlier vehicles, these airbag sensors were basic switches that responded to changes in velocity as the vehicle slowed down during the crash. Once two sensors “closed” to confirm a crash was taking place, electrical current was allowed to flow to the airbag modules.

In newer vehicles, electronic sensors measure a vehicle’s deceleration (negative acceleration), process it mathematically through a computer algorithm, and then compare the measured values to the values stored inside it from crash testing. If the measured values indicate the crash is more severe than the stored crash tests, the control module allows electrical current to flow to the airbag modules.

Once the electrical current flows to the airbag modules, it heats up a “squib” within the inflator that has a small filament inside a container of chemically explosive or flammable material. Once the filament gets hot enough, the chemicals begin burning. This sets off a larger reaction of a chemical called sodium azide within the inflator, which rapidly produces nitrogen gas, along with numerous byproducts.

In some vehicles, the sodium azide inflator was replaced with an inflator using pressurized gas, usually a combination of helium and argon. With either type of inflator, the gas from the inflator then fills the fabric airbag that was folded over the inflator.

As the gas fills the airbag, it increases in size, eventually breaking out from behind its plastic cover and inflating to its maximum size. Driver airbags are generally shaped like a round pancake – just larger than the diameter of the steering wheel – and are normally about 12 to 20 inches thick when filled. Passenger airbags are generally about 2 to 3 feet wide, and fill the space between the passenger and the dash or windshield.

Since passenger airbags are usually 2 to 4 times larger than driver airbags, they require a more forceful inflator to fill that larger size in the same amount of time.

For frontal airbags, the process of sensing the crash and inflating the airbags is usually over in less than one-tenth of a second. As the forces of the crash propel the driver/passenger forward into the airbag, it begins to absorb the energy by compressing and letting some of the gas out through the fabric or through specially designed vent holes.

This explains why many people involved in a vehicle accident in which airbags deployed remember the distinct chemical odor of the inflation gas and seeing smoke in the car.

For side airbags and rollover airbags, the process is similar. A sensor in the side structure of the car, or sometimes inside the front door, detects the rapid deceleration from the side or the vehicle beginning to rotate upwards during a rollover crash. Electrical current is then sent to the side airbags or to the rollover airbags (depending on the type of crash), which causes those airbags to deploy. Although the chemicals and gases may be different than for front airbags, the inflation process is very similar.