ARE SAFETY RESTRAINTS SAFE?
ADVANCED PRODUCT LIABILITY SEMINAR
HOUSTON, TEXAS – JANUARY 1997
Steven C. Laird
Russell, Turner, Laird & Jones
1824 8th Avenue
Fort Worth, TX 76110
Since lap belts were first offered by Ford Motor Company in 1955, automobile manufacturers have been developing and refining a variety of methods for restraining occupants in the event of a collision. These have included manual systems that require the occupant to buckle up, as well as passive systems, that require no action by the occupant.
Although the auto manufacturers impeded efforts to mandate passive restraint systems and delayed the effective date of regulations, beginning in the 1986 model year Federal Motor Vehicle Safety Standard (FMVSS) 208 required a phase-in of passive restraints. By 1990 all new passenger cars were required to have passive restraint systems, and light trucks, utility vehicles, and vans will undergo a phase-in of passive restraints from September 1, 1994, through September 1, 1997.
On September 1, 1993, the National Highway Traffic Safety Administration (NHTSA) issued a final rule which mandates that every passenger car manufactured after September 1, 1997, and every light truck manufactured after September 1, 1998, must be equipped with an airbag and a manual lap/shoulder belt at both the driver’s and light front passenger’s seating positions.
As of July 1990, 36 states, the District of Columbia and Puerto Rico had mandatory seatbelt use laws in effect, and usage rates have dramatically increased from their previous low levels. This has resulted in a decrease in motor vehicle fatalities and serious injuries. However, a number of the older occupant-restraint systems on the road today, including some currently used in new vehicles, are defective and can actually enhance injuries in the event of a collision. What follows is a summary of some of the more common defect theories in occupant-restraint system litigation, and the typical defenses asserted by manufacturers.
II. DEFECT THEORIES
A. Rear-Seat Lap Belt Systems
Although valuations of the three-point lap and shoulder system have been around since the 1950s, until they were recently required to do so, many manufacturers were equipping rear seats of their vehicles with only lap belts. There is an extensive body of scientific and industry literature going back to the mid-1960s which demonstrates that without a shoulder harness, the use of a lap belt can cause serious injuries. In the absence of a shoulder harness to distribute loads over the body, the upper torso can jackknife over the lap belt, causing severe abdominal and spinal injuries, as well as severe trauma to the head. For decades there has been a growing body of evidence that shoulder harnesses will prevent such injuries.
The history behind the failure of most of the industry to voluntarily equip rear seats with three-point systems is enlightening. Even though manufacturers delayed putting the inexpensive three-point harnesses in rear seats of most vehicles sold in the United States until FMVSS mandated them, many of their identical vehicles and model years sold in other countries were equipped with three-point systems.
In the United States, some manufacturers had rear-seat shoulder harnesses as standard equipment in only top-of-the-line vehicles, while others put them in several or all car lines. In the mid-1980s, when the government asked manufacturers to make rear-seat lap belt retrofit kits available to the public through dealerships and to promote their availability, manufacturers were slow to do so and many dealers did not stock the kits. As a result, the vast majority of car owners were unaware of this important safety feature. The following is a brief chronology of events relating to rear-seat restraint systems:
1967 – U.S. manufacturers provide lap belts at rear outboard locations. Volvo introduces three-point belt in rear as standard in certain markets.
1969 – Mercedes-Benz adds three-point belt in rear outboard seats as standard in all markets. Japan requires seat-belts front and rear.
1970 – Victoria, Australia requires three-point belts front and rear and mandates use front and rear. Sweden requires belts in rear-diagonal and static allowed-lap belt only not approved.
1972 – West Germany requires three-point belts front and ream NHTSA requires anchorages for detachable shoulder strap for rear outboard positions (FMVSS 210). Volvo makes three-point seat-belts in rear outboard seating positions standard equipment on all vehicles, all markets.
1975 – Sweden requires three-point emergency locking retractor belts in rear.
1979 – France mandates seat-belts in rear, either three lap belts or three points at outboard positions. New Zealand requires three-point belts front and real, outboard positions
1983 – Saab introduces three-point in rear on all models sold in the United States, which it had provided for years in Scandinavia and Europe.
1986 – National Transportation Safety Board (NTSB) recommends that any manufacturer of passenger vehicles with only lap belts at rear outboard positions provide aftermarket retrofit assemblies to convert belts to integrated continuous loop self-storing lap-shoulder belt systems, and make the availability of these retrofit systems widely known to U.S. vehicle owners.
1988 – BMW, Volkswagen, Audi, Honda, and Saab all use standard rear seat shoulder harnesses on all models. Manufacturers using standard rear-seat shoulder harnesses in only some models include Chrysler with six models, Ford with five, General Motors with 12, Toyota with two, Nissan with one.
1990 – All passenger vehicles sold in United States required to have shoulder harnesses with lap belts in rear outboard seating positions.
B. Automatic Belts
Just as a system with only a lap belt can cause enhanced injury, a two-point shoulder harness system used without a lap belt is also a serious safety hazard. Occupants can be subjected to severe neck injuries due to being “clotheslined” by the shoulder harness when the lower body moves forward. This is true especially for small adults and children. Also, with all of the load being taken up by a single harmless, there is an increased risk of the head spiking the interior of the vehicle. In the event of a rollover, due to the free movement allowed by the absence of pelvic restraint, an occupant can be ejected or, in some circumstances, decapitated by the heavily loaded harness slicing through the neck.
There are two types of automatic belt cases. The first involves a passive restraint system, which is provided with an independent lap belt. This system, which has been used in millions of cars since 1984, uses a non-detachable motorized shoulder harness and a manual lap belt. When the door shuts, the shoulder harness moves into place across the occupant’s body. However, the vast majority of occupants, unaware of the serious risk involved, do not latch the lap belt, either forgetting to do so because there is a harness across their body or intentionally failing to do so because they believe that they are adequately restrained by the automatic shoulder harness. Recent studies have shown that even though motorized shoulder belts are worn in 90 percent of these cars, they are used with the manual lap belt in only 20 percent.
A second type of case involves vehicles that were, surprisingly, manufactured without any lap belts. Due to an apparent loophole in FMVSS 208, certain Hyundai and Volkswagen vehicles were produced with a system that has a shoulder harness and a “knee bolster,” a padded area below the dash. This system was first used by Volkswagen in 1975. The knee bolster allegedly acts as a lower body restraint and replaces the lap belt. In reality, it does neither. Unless a person’s knees are right up against the bolster, there is lower body movement forward and sometimes under the bolster. This dangerous system, which was considered and rejected by other manufacturers long ago, is no longer in use in new vehicles, but was still being manufactured into the late 1980s. There are tens of thousands of these vehicles still on the road.
With the two-point system, the occupant kinematics are dramatically altered by removing the lap belt and relying upon the knee bolster for pelvic restraint. A lap belt, which is in constant contact with the pelvis, begins to restrain the body almost immediately upon impact. However, a knee bolster only begins to work, if at all, in a straight frontal collision when the occupant’s knees have moved forward far enough to contact the bolster.
Depending upon the position of the seat and the length of the occupant’s femurs, the knees may travel several inches forward relative to the seat back. Consequently, the pelvis and lower body will also travel forward the same distance. This results in additional excursion of the body forward, a phenomenon known as “submarining,” which can occur in any automatic system without a lap belt in place.
Submarining changes the position of the occupants body as well as the location of the shoulder harness on the body as the occupant moves forward. The position of the shoulder harness will be higher on the upper torso and, in some circumstances, will be located directly on the neck. When this occurs, the occupant is no longer in a position where his or her body can be efficiently decelerated, and the forces of the restraint system upon his body can no longer be distributed safely. Additionally, significant loading is placed directly upon the neck, which is much less capable of withstanding direct forces than the chest. If the knees strike the bolster but glance under it, the problem is magnified. The resulting trauma or post-impact pressure on the neck can result in fatal injuries, quadriplegia from neck injury, decapitation, or anoxic brain damage.
Another danger inherent in these systems is that they allow not only improper movement of the occupant and forces on the wrong areas of the body, but also put excessive loads on the belt itself. The webbing, which is the actual belt component, stretches to a certain extent during dynamic loading. If the harness is forced to do the work of restraining the portion of the body that is normally held by the lap belt, the amount of potential stretch and upper body excursion will increase. Thus, even if an occupant remains uptight, the risk of his or her head striking the dash increases.
Finally, these systems are completely ineffective in the event of a rollover. A three-point system with a lap belt may prevent an occupant from being ejected, which is critical because the risk of fatal injuries increases several times in the event of ejection. Without a lap belt, there is a much greater chance of the occupant’s body moving out of the system and leaving the vehicle, particularly if the door comes open in a non-motorized system that anchors at the door frame. Moreover, while a three-point system can sometimes prevent an occupant’s head from striking the roof in a rollover, thereby preventing neck injury if the roof does not collapse, there is a greater potential for a head strike without a lap belt. Also, if the pelvis is allowed to move freely during a rollover, significant loads can be placed on the neck by the belt. In some cases this has been sufficient to cause quadriplegia and even decapitation.
The following is a chronology relating to the use of shoulder harnesses without lap belts:
1957 – Volvo introduces the two-point diagonal shoulder belt as an accessory.
1959 – Volvo finds the two-point diagonal shoulder belt unacceptable and replaces it with the three-point belt.
1961 – “. . . a good safety belt should . . . be designed in such a way that. . . there should be no risk of the belt forming a loop around the occupant’s neck . . .
1962 – “With a diagonal shoulder belt the C.G. of the body is usually below the line of the belt and in a forward impact there would be a tendency to slide out from under the belt.”
1962 – “. . . with diagonal chest straps alone the wearer may slide out from under the belt or suffer severe internal injuries . . .”
1965 – “The diagonal belt has no strap to decelerate the lower part of the body and therefore . . . the occupant’s body can submarine under the belt . . .
1967 – “This report describes three cases of fatal neck injuries in subjects wearing the diagonal safety belt, probably caused by the lower jaw being temporarily caught in the belt when the subject slipped out of the belt and was ejected from the car.”
1969 – “. . . the single diagonal belt only . . . does not provide pelvic restraint, which allows the subject’s lower torso to swing forward and rotate out of the belt at impact . . .
1969 – “. . . the diagonal belt has been utilized in three tests . . . In each case the subject was not restrained by the belt, and was flung from the seat, literally hanging himself as rotation occurred about the inferior axis of the belt . . . “
1970 – “. . . this type of strap can cause injuries to internal organs or the neck (when the wearer slides out of the belt). Even a lap strap alone was considered preferable since at least it put the pressure on the well-protected pelvic area.”
1974 – Volkswagen introduces the passive two-point restraint system with a knee bolster.
1976 – General Motors rejects the passive shoulder-belt-only system because of “. . . reservations about the appropriateness of depending on a knee impact surface instead of a lap belt to provide lower torso restraint. We cannot be sure, for example, that a knee impact surface used in conjunction with a passive shoulder belt will adequately protect an out-of-position occupant, a small adult or a child occupant in frontal or angular accidents . . .”
1978 – “As was to be expected, ejection is significantly more frequent with two point shoulder belts that with three point harnesses.”
1981 – “. . . The foregoing discussion implies that the effectiveness of the two-point automatic belt is lower overall than that of the conventional three-point belt system, a conclusion consistent with official estimates published by the US DOT . . .”
1987 – Hyundai introduces the two-point passive shoulder-belt-only restraint system in the United States.
1991 – NHTSA-ODI Investigation EA-91-048 of Automatic Shoulder Belt Failures for 1987 through 1989 Hyundai Excels:
– 48 accidents
– 43 injuries
– 7 fatalities
“A preliminary analysis of the ODI complaint database shows that the complaint rate is higher for the subject vehicles than for the Excels equipped with the three-point manual belts . . .’
C. Intermittent Locking Failure-“Skip-locking”
A common source of injury is a defect in the design of the retractor mechanism, the component of the restraint system that winds the belt and locks the belt in place during a collision. There are numerous types of retractor mechanisms in use today, and their effectiveness in preventing injury ranges from excellent to adequate to dangerous.
Some retractor mechanisms use an inertial locking mechanism such as a pendulum or a caged ball, which locks the webbing when the vehicle is subjected to a certain rate of deceleration. Other retractors use a webbing sensing device, which locks when the webbing is moved relative to the vehicle at a certain speed. Some systems use a combination of the two, as well as a pretensioning device to eliminate initial belt slack in the event of a collision. FMVSS 209 requires that emergency locking retractors must lock before the webbing extends one inch when the retractor is subjected to an acceleration of 0.7g.
Certain retractors are prone to failure due to the use of inadequate materials or poorly designed internal components, which will fail when subjected to reasonably expected load forces. One example of this is a phenomenon known as skip-locking. Skip-locking has been defined as the failure of the retractor to lock under dynamic loads, or intermittent or late locking during the crash pulse. In a typical retractor design that utilizes a rotating wheel with teeth, there are one or more pawls designed to engage the teeth and lock the belt. However, some designs utilize plastic or soft metal that can break or chip, preventing the pawl from engaging or causing it to engage intermittently. If this occurs, the belt can spool out and turn a three-point system into a two point system.
In the mid- to late-1970s, NHTSA investigated certain refractors which were failing when subjected to testing requited by FMVSS 209. It was discovered that some of the retractors had failure rates as high as 50 percent. This resulted in design changes that were incorporated in an attempt to eliminate skip-locking. However, some manufacturers are putting out new vehicles with retractors that are still prone to skip-locking. When such a failure occurs, occupants sustain injuries similar to those involved in rear.-seat lap belt cases, including head trauma and spinal cord injuries.
D. Tension-Relieving Devices
Another defective occupant-restraint system design involves the use of devices designed to allow the occupant to introduce slack by pulling on the belt or leaning forward. These have been called “tension relievers” and “comfort features.” They are more commonly known as “window shade devices,” since they operate much like a window shade.
This feature was introduced by some manufacturers for passenger comfort in the 1970s. In 1976, General Motors began equipping most of its vehicles with these slack-inducing devices, and other domestic manufacturers followed suit. However, no foreign manufacturers adopted these features.
The problem with slack-inducing devices is that they allow several inches of slack to be introduced into the belt, either intentionally or unintentionally, which allows more forward movement by the occupant in a collision. Unintentional excessive slack can be induced from normal movement within the car such as reaching for the radio or the glove compartment.
Excessive slack in seat-belts undisputedly will reduce the effectiveness of a restraint system. The additional excursion results in an increased risk of head contact with the interior of the vehicle, higher values of Head Injury Criterion and greater chest G’s. Also increased peak loads are placed on the occupant due to the greater distance from the seat when the restraint is contacted by the body.
In 1979, NHTSA proposed a ban on tension relieving devices, which was never implemented because of the strenuous objection of the manufacturers. The manufacturers defended the devices by arguing that they encouraged belt wearing and increased usage rates by occupants who were irritated by belts, particularly children and adults of smaller stature.
In 1985, the NTSB concluded that “permitting additional slack in the shoulder belt is not an acceptable way to deal with belt geometry generated by poor anchor design and location,” and that slack introduced can “permit dangerous head contact in a crash.” In January 1986, a NHTSA analysis concluded that “in the real world most tension relievers automatically introduce slacking of the belt with normal movements of the occupants.”
Most manufacturers have since eliminated tension relieving devices from their models manufactured in the 1990s. General Motors announced in February 1990 that it was phasing out the devices to “reduce the potential for occupant misuse.” Chrysler eliminated the devices in their United States built 1990 models. Research has shown that the devices did not result in increased belt use, and that occupant-restraint systems that utilized these devices were consistently less effective in reducing injury than systems without them. Safer solutions to the problem of seat-belt irritation include adjustable anchorages that change the location of the shoulder harness to account for variations in height and seat position.
E. Inadvertent Unlatching
Because of the poor design of some types of buckling devices, the deceleration and other forces generated in a collision axe sometimes sufficient to cause unlatching of the seat-belt. Certain buckle pawls can be depressed by sharp blows or sudden deceleration, allowing the latch plate to pull away and rendering the occupant-restraint system useless. The phenomenon of inertial unlatching has been demonstrated in crash testing done by the auto manufacturers themselves.
In the late 1970S, NHTSA opened an engineering analysis based on allegations that some buckles would release when they were subjected to a sharp blow on the front or back. Subsequent testing by the NHTSA Office of Defect Investigation was conducted to determine the vulnerability of seat-belt latching mechanisms to inadvertent latching. Tests of 225 American cars manufactured over an eight-year period showed that 50 buckles opened inadvertently. Where an individual has been injured in a collision and it appears that he was not wearing the belt post-crash, yet eyewitnesses confirm he had buckled up, he may be the victim of a poorly designed latching mechanism.
F. Integrated Seat-Belt Systems
An inherent problem with occupant restraints presently in use is that their effectiveness is highly dependent upon seat adjustment, because the anchorage is attached to points on the floor, door, and B-pillar. As the seat is adjusted relative to these points, the position of the belt on the occupant’s body, and thus its effectiveness, can change significantly. Variations in occupant height and body size will affect the location of the belt as well. On persons of smaller stature and children, the upper portion of the belt will tend to locate much higher on the body and on the neck.
Since at least as early as 1974, manufacturers have been studying the concept of an “integrated” seat-belt system where the belt is attached directly to the seat. Thus, all anchorage points move with the seat as it is adjusted or moved. Some manufacturers, including Audi; Mercedes; and BMW; have incorporated integrated seat-belt systems into current models Promotional materials claim that the integrated seat-belt system will “provide maximum protection to people of all sizes and in all seat adjustment positions,” and that they will provide “optimum belt alignment in all seating positions.”
Not only will integrated seat-belts eliminate problems relating to poor belt fit caused by seat adjustment and height, but they will provide much greater protection in the event of a rollover. An occupant will be held in the seat more effectively, and greater separation between occupant’s head and the ceiling will be maintained. Additionally, with an integrated seat-belt, unlike belts that are attached to doors or B-pillars, the restraint system will remain effective even if the door opens or if the seat or B-pillar are moved relative to each other.
A. Federal Preemption
In the area of occupant-restraint system litigation this defense is becoming extremely popular. There are essentially three FMVSS that concern seat-belts and their performance:
FMVSS 208 – Occupant Crash Protection;
FMVSS 209 – Seat-belts; and
FMVSS 210 – Seat-belt Assembly Anchorages.
The cases rejecting preemption and the arguments against preemption are too numerous to list here, but there is a body of authority holding that FMVSS 208 (which provides manufacturers three different options for occupant protection systems in terms of performance requirements), was intended by the federal government to preempt common-law liability for failure to install airbags or passive restraint systems. Although this is contrary to the Savings Claude of the National Traffic and Motor Vehicle Safety Act, which preserves common-law liability, in most jurisdictions a plaintiff is not permitted to base a claim on the fact that a manufacturer did not install an airbag. The rationale advanced is that the government adopted a scheme to slowly phase in passive restraint systems, and that to require installation of airbags or passive restraint systems would frustrate that intent.
Some manufacturers have attempted to stretch this concept to encompass any type of occupant-restraint system litigation. So far there are no reported decisions accepting such an extension of the defense. Moreover, appellate courts have made it clear that FMVSS 208 only sets forth minimum standards of performance, and although a manufacturer cannot be forced to select one of three options for occupant-restraint under FMVSS 208, it may still be liable for defectively designing the option it does select.
There are numerous cases at the state and federal level concerning pre-emption arguments which would support both plaintiff and defense. Anyone having a question on pre-emption in restraint cases should immediately consider contacting Arthur Bryant at Trial Lawyers for Public Justice, (202) 797-8600. He is considered to be one of the leading experts in the nation on pre- emption, and should be consulted before mapping out a legal strategy which could inadvertently result in bad case law.
B. Superseding Cause
In any crashworthiness litigation manufacturers inevitably argue that the plaintiff’s injuries were not enhanced by the design, and that the force of the collision was so great that the plaintiff would have sustained the same or worse injuries irrespective of a different design.
In an occupant-restraint system case, defendants will argue that state-of-the-art occupant-restraint systems are ineffective over 35 m.p.h., and that at such speeds any design will permit serious injuries. If the plaintiff has sustained a severe brain injury, a new defense tactic is to argue that the plaintiff sustained what is called diffuse axonal injury, caused by rapid rotational acceleration or deceleration of the brain. The defendant will contend that even if the occupant had been prevented from striking the interior of the vehicle by a better restraint system, the rotational forces were so high that the occupant would have sustained permanent brain damage.
Under such circumstances the defense will dispute not only the cause of the injury, but the nature of the injury itself. Proof of causation will require an analysis by an accident reconstructionist, a biomechanic, and physicians. It therefore becomes critical for the plaintiff’s attorneys to thoroughly document the care and treatment of the plaintiff from the scene of the accident forward. This should include not only acquisition of all pertinent medical records and interviews with treating physicians and other medical personnel, but interviews with eyewitnesses, paramedic personnel, firemen, ambulance drivers, and anyone who could possibly have any information concerning the physical condition of the plaintiff at any point in time following the accident.
C. Unforeseeable Misuse
Manufacturers will frequently argue that the occupant-restraint system was being used improperly, thereby defeating the belt’s effectiveness. A common contention is that the injured plaintiff did not follow the instructions in the owner’s manual concerning use of the restraint system. Manufacturers will also contend the occupant was not seated correctly or that the seat or belt was positioned improperly.
In some cases this may be the result of the often confusing and ambiguous statements in the written materiels provided. However, even where the plaintiff has not followed the owner’s manual to the letter, counsel for plaintiff should determine if there is a defect based on failure to warn. While manufacturers usually give a list of do’s and do not’s in their owner’s manuals, in many cases there is no information given as to the consequences of the failure to follow those instructions. If a person is advised that serious injury or death is a potential result, he or she is much more likely to follow specific instructions as to belt adjustment and seat position.
Non-use or misuse are easy arguments for defendants to make, since belts are often unbuckled post-crash by other passengers or people arriving at the scene. Also, when vehicles come to rest after a collision, even a properly seated and belted occupant is rarely in a normal seating position. This defense should be anticipated and taken out by early, thorough investigation.
Statements from witnesses should be obtained to document the plaintiff’s position and use of the belt pre-impact, as well as position post-crash. Bruises and lacerations on the body left by the webbing will identify the precise location of the belt at the time of the collision. These should be extensively photographed and videotaped immediately, before they disappear. The restraint system itself may contain critical evidence regarding the belt’s position and how it performed, such as marks on the webbing from retractor components, or even skin tissue or honed.
Even with the availability of research and literature demonstrating the defective nature of many occupant-restraint systems and the well-documented history of the failure of auto manufacturers to remedy known defects in their restraint system designs, these are extremely difficult cases to win. Taking on an auto manufacturer in a major injury case involving a restraint system design defect is expensive.
The plaintiff’s attorney must be prepared to spend up to and above a six-figure amount to work up and try some of these cases, and should expect that the manufacturer will spend two to three times that amount. Certainly not every case represents this type of expenditure, but the problem is that the attorney never knows at the outset what the ultimate necessary costs will be. The plaintiff’s attorney must be committed to obtaining the best experts from around the country in accident reconstruction, occupant-restraint system design and testing, biomechanics, automotive engineering, and case-specific fields of medicine. A state-of-the-at demonstrative evidence presentation at trial is essential, and may require full-scale mock-ups and crash testing. Despite the financial and legal hurdles facing the plaintiff’s attorney, these cases can be successful provided they are worked up properly and afforded sufficient time and resources.
– Steven C. Laird, Laird & Cummings, P.C.,
1824 8th Avenue, Fort Worth, Texas 76110, 817-531-3000, www.texlawyers.com