Why Are Americans At Grave Risk Of Catastrophic Injury In Rollover Accidents? OverviewIn the United States every year, more than 355,000 Americans are injured or killed in rollover accidents. Of those victims, about 10,000 die and approximately 14,000 are seriously, severely or critically injured. Study after study has proven that the primary sources of injury associated with the most severe injuries are vehicle roof pillars, rails and headers. Further, the body regions of the head (brain), face and neck (spine) have the highest frequency among the severe injuries. Despite the fact that rollovers only represent about 3% of the many types of accidents happening on our highways, the National Highway Traffic Safety Administration (NHTSA) has found that more than 30% of all fatalities and catastrophic injuries happen in rollovers. Rollover casualty rates are now three times higher than frontal rates. And, by far light trucks (e.g., sport utility vehicles, vans, etc.) are the largest class of vehicles in rollovers. Recently, government investigators conducted a large study of rollover accidents and found that there is a direct correlation between the extent of occupant compartment intrusion and an increased risk of serious head and neck injury. Despite this knowledge, neither NHTSA nor the automotive industry has stepped up to the plate and pursued solutions to this human tragedy. In fact, there is clear evidence that the industry has often taken steps to thwart NHTSA’s well-intended efforts to alter FMVSS 216 and require much stronger roof structures. The sad truth is that Americans are dying and being maimed every day of the year simply because no one wants to admit they made a mistake and disregarded the obvious—roof structure collapse causes injury. While the litigation posture of the motor vehicle industry has been to consistently deny the importance of roof structure in preventing catastrophic injury to belted occupants, even these staunch opponents of structural safety have been caught saying the opposite within the confines of their hallowed halls. This is the story of one of those companies and the choices it made, which have condemned thousands of people to suffer catastrophic injury. In 1987, the Harris family decided to purchase a new van. They purchased a 1987 Ford Econoline conversion van, which fit their needs. The sales brochure, which enticed these folks to buy the Econoline, touted its safety features, including a “safety-related roof structure.” Several years later, while the Harris’ were on vacation in North Carolina, an accident ensued which led to the virtual destruction of Mr. Harris’ life, as he then knew it. While they were driving along Interstate 40, another car went out of control and struck the left rear corner of the van. The van yawed counterclockwise, tipped up and rolled over. After rolling three times, the van came to rest on the passenger side (where Mrs. Harris was seated.) While Mrs. Harris and her four children literally walked away, their husband/father was not so fortunate. As shown below, during the accident event, the front driver’s portion of the van caved in more than twenty inches. As this occurred, the seat belted driver was struck by the collapsing roof, causing his head and neck to be compressed and forced into violent flexion—resulting in both spinal column fractures and spinal cord injury. Mr. Harris was instantly rendered a quadriplegic. The tragedy of this exact type of accident and injury has been documented over the years by researchers around the world. As this article is being written, there is an ensuing debate between the NHTSA, the automotive industry and consumer organizations concerning the necessity to modify FMVSS 216 to obtain stronger vehicles. Yet, never before publicly revealed internal documents demonstrate the inconsistency of the industry’s public position. And, just as importantly, we have now learned that the industry’s public posture is fully dependent upon its litigation defense to the victims of roof crush. Here is the evolution of this debate, which ultimately caused the violent irreversible injury to the Harris family. In the 1960s and 1970s, on this continent and in Europe, car companies observed that occupant safety was dependent upon the preservation of vehicle survival space. At Ford, its auto safety engineers warned that people have been injured by roof crush and that with the development of effective seat belts and the industry’s push to enact mandatory seat belt laws, there should be serious concern that belted occupants will be at greater risk of injury because of roof crush (since they will remain relatively upright during rollovers). Through the 1960s and early 1970s, Ford and General Motors engineers wrote that it was critical to maintain survival space so that the vertical space defined by the seated height of at least a 50% percentile person is not violated. At the same time, Ford, General Motors and the Society of Automotive Engineers (SAE) debated whether roof strength should be judged by a dynamic or static test. The SAE proposed conducting drop tests from two feet to establish a repeatable procedure, which would allow car companies to design to prevent massive intrusion. This testing by Ford established that its current product line would not meet such a criteria. General Motors reached the same conclusion and then developed a static push test intended as an alternative to the SAE drop test. The static test method was then proposed to NHTSA and incorporated into its suggested roof crush standard. As proposed, FMVSS 216 would have required testing in succession to both sides of the roof structure by applying the load plate onto the roof at the front A pillar/windshield intersection on the driver and passenger sides. The proposed standard also required that the plate not move more than 5 inches before the force reached 1.5 times the weight of the vehicle. The auto industry opposed these criteria. Ford advised the government that testing the second side was unnecessary since the results would not be different—stating specifically that the vehicle’s windshield would remain in place and thus there would be little difference in the performance of the vehicle’s structure. Ford and other industry representatives asked that the crush criteria be extended to 10 inches and that the strength to weight ratio be lowered to 1 time the vehicle’s weight. Fortunately, the NHTSA rejected the proposed changes in strength to weight and crush displacement. But, unfortunately, the NHTSA withdrew its criteria that the second side of the roof be tested. That decision has singularly led to the production of millions of vehicles that have less than one-half the strength of 216 test results once the windshield is damaged (e.g., “second contact”). The following chart summarizes that result. During the development of the federal minimum standard, the industry also honed its public mantra that roof crush may be “associated” with injury, but there is no evidence that it is “causally” related. What no one really understood was that this assertion was not based upon any scientific study. Instead, in the instance of Ford, it was based upon one of its engineers “studying” four rollovers in which three of the occupants were ejected or tossed around in the car because they were unbelted and in the fourth example the finding was inconclusive about whether or not the fatal injury was due to roof crush. Nevertheless, Ford, General Motors and others have continued to stress this unsupported assertion. Over the next two decades, car manufacturers in this country essentially ignored the need for rollover protection. Instead, they were institutionally directed to address (and in most instances oppose) the need for frontal protection, driven by the various passive safety proposals made by the NHTSA. Nevertheless, there were some engineers within the industry that did not ignore the signs of danger. For example, in 1976 a pick-up truck on the GM proving grounds rolled over when a tire failed. The seat belted passenger in that truck was fatally injured (he suffered quadriplegia and died of complications) when the roof structure collapsed in on him. The GM test driver walked away but in a report to the company he urged that roll cages be installed in all vehicles used on the proving grounds to protect against this risk of harm. It is now indisputable that both GM and Ford adopted in-house requirements that all high profile vehicles driven at high speed on their proving grounds be equipped with roll cages. While totally inconsistent with its litigation stance, this practice is, of course, completely consistent with Ford’s Automotive Director’s comments to the government in 1989, when he recommended that a “survival zone” be developed to address roof crush and rollover protection. A few years earlier, some of Ford’s engineers warned members of the corporation’s Board of Directors that steps should be taken to strengthen the light truck fleet to minimize the increased risk of harm presented by these vehicles in an environment guaranteeing a heightened risk of rollover. The report specified that Ford’s Light Truck Division should place a high priority on increasing roof strength, which must be obtained at all four corners of the vehicle and significantly surpass the strength requirements of FMVSS 216. Despite these proposed goals, a Committee of the Board of Directors was then asked to only approve a watered down version of this directive—which it did. Thus, through the 1980s, the 1990s and into the present decade, Ford light trucks are built with insufficient strength so that these vehicles cannot support the weight of the vehicle if the windshield is broken out. A photograph of one such vehicle, ready to be dropped from one foot is depicted below, together with the resulting roof crush damage. As time has passed, the industry has become entrenched with the mantra that roof crush is not related to injury. In 1990, that mantra was fortified by the publication of the Malibu II study, generated by GM litigation experts. The conclusions of this study were that the risk of spinal cord injury in rollovers exists even when the car includes a sturdy non-deformable roof cage. Touted as the final answer on this topic, this study has been used over and over in courtrooms across the country and provided to the NHTSA as the “scientific answer” to this unfortunate public safety problem. The authors of Malibu II state that seat belts cannot provide protection in rollovers because there is very little distance to the roof and occupant excursion is inevitable. These authors likewise opined that neck injury always occurs when the head is arrested against the roof, the roof impacts the ground, and the torso continues to move vertically and compress the neck to failure. The industry used this study with impunity for many years, because the underlying data was not revealed. However, within the past few years, engineers involved in litigation and several independent researchers have had the opportunity to study the underlying data and the result is the astonishing conclusion that Malibu II proves that roof crush causes excessive compressive (in the z axis of the neck) spinal loading of the test dummy’s neck. In fact, once Malibu II’s results are analyzed using a compressive neck force threshold, which is more closely comparative to human injury tolerance, it becomes clear that only when the test vehicles did not include a roll cage was the measured neck force sufficient to create a risk of catastrophic injury. The following summary of Malibu demonstrates this conclusion. Despite these conclusions, the industry continues its unsupported assertion, both in courtrooms and in opposition to NHTSA’s current investigation of the efficacy of FMVSS 216. This year, Ford, General Motors and DaimlerChrysler have written to the government and stated that there is no causal relationship between roof crush and injury, and therefore there is no need to toughen FMVSS 216. What has not been disclosed is that these “official” comments have been written by the litigation testifying experts who travel around the country trying to save the industry from well-deserved verdicts. Recently, one such expert, Ken Orlowski, confessed in court that he authored Ford’s comments to the government. Faced with the self-serving reasons for misleading the government, there is a real question whether NHTSA should place any reliance upon this official response to the government’s investigation of the need to strengthen FMVSS 216. Today, vehicles comply with FMVSS 216 with significant variation. If one were to consider strength to weight as the appropriate test of a vehicle’s safety, most engineers believe that a 3-to-1 or 4-to-1 ratio would produce a safe vehicle (defined as one that will resist massive roof crush). Using this criteria, the following chart compares many of the vehicles on the road today. As the NHTSA looks again at the importance of modifying and increasing the roof crush standard, lessons of the Harris’ tragedy should not be forgotten. History Should Not Be ForgottenOn November 13, 1968, Ford’s Executive Engineer in its Safety Engineering Department sent an in-house letter to several top echelon engineers at Ford to address the “Rollover Impact Protection Requirements” issued by the federal government. Mr. Brilmyer, a Ford Engineer, provided the following criteria for roof strength: “Improved Roof Strength” Excluding the rollovers terminated by impact with rigid and/or fixed objects, the roof of a vehicle should be strong enough to sustain twice the weight of the vehicle with no permanent structural deformation.” Within General Motors similar analysis was being conducted. In 1971, GM provided the following affirmation of the importance of preventing significant roof crush in the event of a rollover. “General Motors shares the Administration's (U.S. National Highway Traffic Safety Administration) concern for reducing deaths and serious injuries in all accidents, including rollovers. To help reduce the possibility of head and neck injuries in the event of occupant contact with the roof in any type of accident, most 1971 General Motors passenger car models incorporate a new double steel roof with a contoured inner panel." General Motors went on to recommend the adoption of a roof crush performance criteria known as the “zone of non-encroachment.” This criteria would define the area within the occupant section that should not be intruded upon in testing, with the idea being that if you can preserve a zone in which the person sits and the roof does not violently intrude or allow ejection, then the risk of injury from roof crush is significantly minimized. As early as 1971, Ford engineers expressed concern that the government static roof crush test presented an unrealistic structural loading, and that the preferable test of roof strength was a “sled roll” in which the vehicle is mounted on a dolly and driven sideways down a track and released at a staged point. By July 1987 (revised December, 1987), Ford’s Light Truck Safety Design Guideline Strategy included the following comments relative to rollover and roof strength:
Recognizing the importance of roof strength to occupant safety, prior to 1990, Ford established an internal criteria requiring that: “…light trucks meet FMVSS 216 with less than 5 inches of crush applying a load which is 1.85 times the weight of the vehicle.” Unfortunately, because Ford did not judge the strength to weight ratio without a windshield and in a more lateral load than the 25 degree application of force in FMVSS 216, the end result has been cars and trucks that are woefully inadequate to prevent massive roof crush. The Injury Causation DefenseIn virtually every case involving rollover and roof crush, the defense argues that the injury—whether its head injury or spinal cord injury—is unrelated to roof crush. To support this contention, it is typical for the manufacturer to rely on the Malibu II series of tests and then conduct a few simple tests to strengthen its position. Typically, the defense conducts a “spit test” in which it takes an exemplar vehicle and puts it on a “301 spit,” puts a person in the vehicle and while he is wearing the seat belt, the vehicle is slowly turned over. The camera then captures the movement of the person toward the roof. Typically, during the spit test the person’s head will come in contact with either the roof rail (area above the side door), and the roof panel itself or go out the side window. Then, a second test may be conducted in which a dummy is put in the vehicle and belted. When the vehicle is inverted, it is typical for the defense to have the dummy’s head either on the roof or very near it. Then, the vehicle is dropped from at least 18 inches and even when the vehicle has been modified to include a so-called roll cage, the defendant’s test shows a very high compressive force to the dummy’s neck. To counter these tests, the victims must either confront these tests with blazing cross-examination or conduct their own costly testing. It is relatively easy, although expensive, to re-do both of these tests and show that the human excursion is hardly ever as great as the defendant shows it. Likewise, if the dummy is positioned in a more typical inverted stance, there will be several inches of clearance in many vehicles. Further, if the added structure is designed properly, it is highly unusual to have high neck loads. It is quite important, however, to stress that a rollover is nothing like a drop test. And, almost all major roof crush is the result of significant load being applied in a direction that is lateral to the roof rail. Thus, the force is being applied laterally and the person’s head is being impacted because the roof is buckling at a high rate of speed both vertically and laterally.20 The person’s head may be on the roof or the rail, but the direction of force is from the side and not in a direction vertical to the person’s seated position. The Malibu DefenseIn 1990, several GM engineers and consultants published a paper describing a series of rollover tests they conducted using Malibu passenger cars. Eight dolly rollovers were performed; four used production vehicles and four used Malibu cars with built-in roll cages. The dummies were belted and placed in the vehicle so that when the vehicle tipped over, the dummies would move toward the roof to the same degree that the authors believed a person would move. Instrumentation measured some of the forces imposed upon aspects of the vehicles and the test dummies. The authors identified a compressive neck load of 2000 N as the level at which there was a “possible injurious injury” (PII). Using this threshold, the authors found that virtually every roof impact on the driver’s side caused a neck reading in excess of 2000 N. It was, therefore, concluded that each and everyone of these impacts was potentially injurious, thus establishing that the strengthened roof system was irrelevant to neck injury. Efforts to criticize the Malibu II publication need to be carefully crafted. A few of the important weaknesses of this study are described here. First, the neck of the Hybrid III dummy is known to be extremely stiff in compressive loading. It has never been shown to be biofidelic in that direction. Second, studies published by the auto industry and others have shown that no human will suffer any serious spinal cord injury with 2000N. Instead, there is a growing consensus in the scientific community that compressive neck loading forces on this very stiff test dummy must exceed 8000 N as a predictor of potential serious injury to a human. The other issue is the defense assertion that injurious neck loading occurs before roof crush. That conclusion was refuted by automotive engineers employed by one Japanese manufacturer in a well-documented research paper presented in 1991 at an International Experimental Safety Vehicle Conference. The charts presented demonstrate the authors’ conclusions on that topic are diametrically opposite the Malibu conclusions. The very intense debate over the importance of roof strength in either preventing or mitigating injury in rollover accidents seems to center on the causative relationship between roof crush and injury mechanics. This debate has served to create a “strawman” argument. That is, while some researchers have published and shown a direct correlation between roof deformation and the risk of head and/or neck injury, others have disputed this mechanical relationship. Both sides of this debate have conducted tests and studied the accident statistics in an effort to justify their respective positions. Much of this debate has spilled over into the litigation arena when injured motorists sue vehicle manufacturers alleging harm because of roof crush. If, however, we were to pull away from the rhetoric of lawsuits, the issue becomes less controversial. That is, what possible harm can result from strengthening the structure that supports the roof in an effort to minimize compartment collapse in the event of a rollover? Absent any added harm, if there is a chance that even one life can be saved or one catastrophic injury avoided, then why ignore this potential benefit? ConclusionThe disproportionate number of fatalities and serious injuries in rollover accidents obviously requires more attention by the automotive industry and NHTSA. Absent some legitimate technical bases for not making vehicle structure less likely to crush in on the occupant space in a rollover, both manufacturers and the Agency should pursue and execute new minimum standards to improve vehicle safety. Manufacturers should continue to strive to design and test its vehicles to far surpass any such new standard, and to include criteria that incorporate a systems approach to rollover protection by integrating a seat belt/roof crush/performance-injury criteria. Only by pursuing and executing this type of design plan can we prevent more victims like the Harris family. |