Over the past few years, there has been a public outcry about the deaths of almost one hundred motorists in low speed motor vehicle accidents because of air bags. Children and small adults continue to die because of the violent exposure to inflating air bags. We cannot, by ourselves, find the solutions to this expanding public health issue, but we can and should understand the causative factors producing these tragedies. With this knowledge, we can if it is appropriate, recommend either the pursuit of common law claims, or counsel perspective clients against litigation arising from air bag induced injury or fatality.
Air bag systems were installed in the United States in thousands of automobiles during the model years 1974 through 1976. These air bags were designed and installed in large size vehicles by both General Motors Corporation and Ford Motor Company. At the time, the intent was to provide frontal crash protection for the general population of motorists who, on the whole, were not wearing seat belts. Consequently, the air bags installed in the 1970s were quite large in circumference -- occupying fully the entire front of the vehicle from door to door. The very few accident studies of early vintage air bag crashes concluded that these systems were working to minimize injury potential. Those studies were consistent with laboratory testing which demonstrated that these passive restraint systems provided protection in barrier impacts through 30 to 40 mph crash speed range. Publications in recent years have analyzed the field performance of these older systems. Looking just at driver's side air bag system performance, these authors determined that the system was found to be 21% effective in preventing AIS 3+ injuries, but was -34% ineffective for AIS 2+ passenger injury. Many of the airbag inflation injuries found in the research of the systems performance -- as well as the much more recent data obtained since 1989 -- occurred in moderate severity crashes without distortion of the occupant compartment. Thus, the deployment of an airbag under some circumstances has the potential to seriously injure or kill, and it does not always depend upon the severity of the crash. As David Viano of the GM Biomedical Science Department stated a few years ago,
"The high energy release of an airbag may injure an occupant against the system at the instant of deployment. Blocking the path of deployment increases pressures in the cushion during gas generation and develops high forces on the occupant. Since the force occurs with high velocity, there is a risk of injury by a Viscous mechanism."
Public and secret lobbying efforts of the auto industry caused the federal government's delay of the starting date of mandatory passive restraint criteria, [FMVSS 208] for more than a decade. During this period of time, automobile manufacturers chose not to pursue the mass production of motor vehicles with air bags. In the calendar years 1980 and 1981, Daimler Benz introduced in Europe a test fleet with full frontal protection by air bag restraint. Then in the 1982 model year, Daimler Benz introduced a driver's side air bag system (along with a manual lap and shoulder belt) in Europe, along with a three point passenger side manual seat belt with a pretensioner retractor. Daimler Benz then introduced air bag systems to the U.S. market in 1984, offering it first as an optional piece of equipment and then it became standard equipment. Chrysler Corporation became the first American manufacturer in the 1980's to introduce air bags into its vehicles. And, with time, the remaining manufacturers have installed air bags for both driver and passenger positions -- as a direct result of the mandatory passive restraint performance criteria adopted by the NHTSA. It is estimated that by the year 2000 there will be over 50 million vehicles on the roads with air bags, and each year there will be literally hundreds of thousands of air bag deployments.
The air bag system, like any other safety device, needs to be viewed in connection with the benefits and risks it poses; that analysis is important if efforts are to be made to minimize the risks associated with air bag equipped vehicles. It is critical to stress that air bags and seat belts save lives. Every vehicle which includes an air bag system provides for incremental safety that was unavailable to Americans during the 1970s and 1980s. While inflatable restraints are not a panacea, they are a significant advancement in the quest to reduce trauma on our highways. How well these devices function in specific accident scenarios does, however, vary because of design features, variability in accident modality and occupant kinematics.
A review of over a dozen recently published papers has allowed for a study of the details of one hundred and fifty-nine frontal accidents involving air bag deployment. These studies focused primarily on the injuries and fatalities to adults and children in frontal crashes. While there are differences of opinion about the causative relationship between air bags and injury, it is necessary to account for the trends in the accident data. It is also important to study the causative relationship between some of the events precipitating fatalities and the deployment characteristics of the air bags installed in vehicles. This analysis can only lend credence to the adage that everything we do can be done better.
Most of the reported adult injuries and deaths due to air bag deployment involved drivers rather than front seat passengers. In these data there were 16 driver fatalities and 4 passenger fatalities. Of course, the reported fatalities to children provide a different picture. In a four to five year time period, the NHTSA has studied 96 air bag induced deaths to adults and children under the age of nine.
In the fatalities produced, it was observed that a majority of the adult motorists were female and under 50 years of age and unbelted. However, there was no different injury pattern between the belted and unbelted fatalities. Between the two groups, there was a proportionately equal number of deaths due to brain injury and spinal cord trauma. The average crash speed in these deaths and in many of the seriously injured accidents investigated were approximately 12 mph. A majority of the deaths to children over age one occurred in reported instances where the child was unrestrained. Most but not all of the infants who died were seated in the vehicle's front passenger seat in a rear facing child seat. The risk of injury from an inflating air bag has been a consideration for all occupants for many years.
In recent years, it has been widely agreed that air bag protection is less necessary in low speed collisions. In fact, manufacturers such as Mercedes Benz has designed air bags which deploy at 12 mph delta V if the driver is unbelted and at an 18 mph threshold if the driver is belted. This dual threshold design has been gradually introduced into the American market by other European car companies as well. This staged deployment is perfectly consistent with the published data suggesting that the risk of severe injury does not arise until a delta V of 18 mph.
Old laboratory studies confirmed what we are now seeing in field accidents: "high" loads can be developed on occupants who are within the path of an inflating bag. As in other dynamic circumstances, the risk of injury depends on the system, the environment and the alignment and position of the occupant at the time of bag inflation. Clearly the human body parts at greatest risk are the head, neck and torso because of their (foreseeable) close proximity to the system. In order to minimize the danger of air bag head injury in low speed accidents, car companies like General Motors developed dual deployment air bag systems, which provide for proportioned deployment with the dual deployment of air bags. This system allows for a less violent deployment with a delta V below 18 mph.
Real world "near position" injuries are associated with a wide range of crash severities, but most troubling are those circumstances when the Delta V is below 25 mph, because these are accident circumstances which should, ordinarily, cause little or no serious injury. This exposure to injury occurs under a variety of scenarios, including the driver or passenger who has slumped forward from illness or drowsiness; or moved forward because he or she is not belted, or because a child seat extends almost to the instrument panel, or because of pre-impact braking which moves even the belted occupant forward toward the air bag unit.
Air bag induced injuries are, by the very terms used, injuries caused when an occupant is impacted by an inflating air bag. NHTSA has informed Congress that air bags can have adverse effects for small stature people, older people and out of position children.
There is some agreement amongst car companies that tethered air bags are safer than untethered bags. The tethering of the bag reduces some of the "bag slap" induced injuries. Likewise, the overall size of the air bag will influence its impact characteristics. The smaller European "face bag" is less forceful and the top mounted vertically deploying passenger side air bag reduces the forward capturing velocity of the standard passenger bag. In 1990, General Motors provided the following comments:
" [O]ur analysis indicates that upward deploying S.I.R.s may place fewer occupants at risk of injury as a result of being impacted by a deploying air bag when they are out-of-position. . . . [W]e believe that upward deployment may offer greater potential for total harm reductions for front seat occupants in frontal crashes at speeds above the deployment threshold."
The accident data suggests that air bag induced injuries to unrestrained occupants are a result of the occupant moving "out of position" and being struck by the inflating air bag during low speed collisions. The obvious solutions to this dilemma are to compel seat belt usage, move all children to the rear seat, change the deployment timing, and alter the deployment rate. To minimize the risk of deployment induced injuries, air bags should be designed to deploy faster when the seat belt is not worn. This allows for complete inflation before the occupant moves substantially forward in the seat. In 1981, Mini Cars studied the issue of the "near position" child and found that injury was due to bag slap and catapult; this researcher also found that modifying the bag folding, storage methods, and inflator flow significantly reduced the risk of injury.
A high number of head and neck injuries have been reported in air bag deployments even when the motorist is restrained. The mechanics of this type injury suggest that the seat belted occupant is moving forward in a relatively upright position and coming into contact with the inflating air bag so that the neck is either placed in compression or extension. To minimize seat belt excursion to the "out of position" stage the seat belt must be designed to lock-up when deceleration of the vehicle first begins -- through braking -- or as a result of occupant movement within the seat belt -- by using web sensitive retractors which are tuned to lock up at .35g. Additionally, the environment of the driver's position needs to be studied to deal with people of small stature. Some possible incremental solutions would include adjustable pedals, a pretensioning retractor and changing the characteristics of deployment -- including a reduction of the deployment rate, tethering the bag, and widening its coverage which would also reduce "bag slap."
The current state of the art would allow air bags to be designed with improved folding patterns, special fabric coatings, and modifying the deployment rates. These changes will "soften" the impacting forces to the air bag. Undoubtedly, these changes will provide incremental improvements and changes in injury potential.
The dilemma causing fatalities to children should have been addressed over the past several years through design and informational alerts by manufacturers. Choices which would have prevented these tragedies include: (1) standard integrated child seats in the rear seat of every vehicle, (2) front seat belt systems suitably adjustable for children , (3) sensors which prevent air bag inflation at delta V below 20 mph and when the weighted object in the front passenger seat is below 60 lbs; and, distinctive warnings posted in a clearly visible location in each vehicle.
Educating the public to the need to remain as far away from the air bag container is critical to a reduction in deployment injuries and deaths. Both motor vehicle manufacturers and the government have a responsibility to alert consumers to these inherent risks in the current air bag modules. Designs should have been incorporated into an air bag equipped cars in anticipation of these issues. At this point, motorists need to be informed of the grave risk that they can be exposed to by a safety device that must still be viewed as a life saver. What remains now for the victims of yet another colossal mistake on the part of vehicle manufacturers is the tort system. Car companies must be held accountable, and they should not avoid responsibility because of NHTSA's oversights.