Situational Science

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A high-profile seat-back failure case that delivered a $43 million plaintiffs’ verdict this summer also exposed major flaws in the work of a renowned researcher, whose studies are often cited by manufacturers in arguing against stronger vehicle seats.

Dr. David C. Viano, a former General Motors scientist, now a private engineering consultant, was retained by seat designer and manufacturer Johnson Controls to testify that the 2000 Dodge Neon seat at issue in Heco v. Johnson Controls was not defective, based, in part, on statistical analyses performed by Viano and his colleague at ProBiomechanicals LLC, Chantal Parenteau, using the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS).

A prolific researcher, Viano has reversed his positions on seat designs over the course of his career, from a proponent of stronger seat backs, and seat integrated belts as a GM Principal Scientist, to a defender of weak seat backs as an expert witness defending auto companies against litigation claims. As a high-profile figure in this area of automotive design, Viano’s current views have been accorded a weight that, his critics charge, is not supported by the quality of his research. 

Viano declined to respond to these criticisms.

The Heco case emanated from an August 4, 2007 rear-impact crash. Dezmila Heco was stopped at a light in Essex, Vermont when she was rear-ended. Although Heco was wearing her seat belt, the 2000 Dodge Neon’s restraint system failed when the seat back collapsed. The force of the crash threw Heco into the rear of the occupant compartment, where she broke her neck, leaving her a quadriplegic. Over the course of the two-week trial this summer, a Chittenden County, Vermont jury found that the seat in Dodge Neon, designed and manufactured by Johnson Controls of Milwaukee, Wisconsin, was defective and the cause of her severe injuries. It awarded Heco and her sons more than $43 million.

On June 4, Superior Court Judge Geoffrey Crawford in Chittenden County, Vermont ruled that Viano could only use NASS-CDS data to make two general, and non-controversial points at trial: that rear-impact crashes resulting in serious injuries were relatively rare compared to that of frontal collisions and that rear-end collisions are less dangerous than frontal collisions. (NASS-CDS data is populated by detailed crash cases selected from a sample of police crash reports; the National Highway Traffic Safety Administration and other researchers use the data to investigate injury mechanisms and track trends.)

Crawford’s ruling stripped away most of the meat of Viano’s testimony. He could not use NASS data “to support specific claims about the safety properties of different seat designs and the incidence of injury for ‘stiff’ v. ‘yielding’ seats,” Crawford ruled – a critical aspect of Viano’s expert opinion.

James L. Gilbert of The Gilbert Law Group, in Arvada, Colorado, represented the Heco family with Robert Langdon of the Lexington, Missouri firm, Langdon & Emison.

“The attorney can’t have his or hers eyes glaze over when the subject of statistics comes up,” Gilbert says. “You have to learn what the opinions are and whether there is a legal and factual support for them. You can’t let people get away with a statistical opinion without a statistical background. [Viano] was willing to opine on statistics, but he didn’t have the background to make those opinions. When it came down to statistics, he was pretty much unqualified.”

NHTSA has not upgraded the core requirements of the seat back regulation, FMVSS 207, since 1967. Nearly 25 years later, the agency admitted in a report that the current standard is inadequate to ensure that the seat does not fail when a car is subject to a severe rear impact. This regulatory failure, which the agency has yet to correct despite decades of advances in automotive technology, has resulted in unnecessary deaths and injuries to vehicle occupants.

In the past ten years, a “debate” has raged in the professional literature comparing “stiff” seats – which retain their upright integrity in a crash with “yielding” seats, which recline rearward in impacts. Some researchers, such as Viano, have produced work supporting the view that the yielding design results in fewer injuries. Others, such as Dr. Kenneth Saczalski, have published technical papers criticizing Viano’s work and positing that yielding seats are not only injurious to the front seat occupant but also that the collapse into the rear occupant area exposes rear-seated occupants like children as well to potentially serious injury or death. 

Saczalski says that many of his academic disagreements with Viano have centered on the misuse of crash statistics, including what Saczalski says is Viano’s technique of mixing data subsets to produce a result that makes weaker seats look better in real-world crashes

“He’s been taking a limited amount of data and even smaller portions and extrapolating to the larger population with inaccurate statistical measures,” he says.

In his Motions in Limine ruling, Judge Crawford said:

“The sample of the NASS study – 5 cases in all – is too small to generate meaningful information about the mechanism of injury and the desirability to the occupant of having a seat which remains in the upright position (plaintiffs claim) or that rotates backwards (defendant’s claim.) The motion is granted to exclude this type of specific design testimony based on the NASS results because the expert’s conclusion is derived from a sample which is too small to have any degree of reliability,” Judge Crawford ruled.

Viano’s Statistical Skills

Viano is a prodigious publisher of scientific papers and books on a wide variety of topics relating to injury mechanisms including issues at the heart of the Heco case – the role of seat backs and obesity in crash-related injuries. An SAE press release about an award he received in 2010 noted that Viano had published more than 300 papers. After retiring from GM in 2002, Viano founded ProBiomechanics, and is an Adjunct Professor of Biomedical Engineering at Wayne State University in Detroit. He is a regular contributor to the Society of Automotive Engineers publications, and the Traffic Injury Prevention journal, of which he is the chief editor. He is also a frequent defense expert in automotive product liability cases.  

Gilbert and attorney Robert Langdon had challenged the statistical foundation of Viano’s expert report at a May hearing after engaging a statistician to review Viano’s methods. Dr. Norma Hubele, a professor emeritus of statistics at Arizona State University, the co-author of a statistics textbook, and now a private consultant, was highly critical of Viano’s statistical methods and conclusions.

Viano testified that he was not performing a statistical analysis that required a Ph.D level of understanding – only basic mathematical computations on the data. Hubele strongly disagreed. She examined the source code Viano and Parenteau used in calculating the statistics that served as the foundation of their conclusions.  In her expert report, and in hearing testimony, Hubele said that the pair had used the wrong methodology, too-small sample sizes, the incorrect standard error for computing their national estimates, risk rates and exposures and used non-standard confidence intervals. The pair had failed to use the correct software in making their calculations. In concert, these errors rendered their conclusions statistically meaningless and unreliable, she said.

“In my opinion, Viano demonstrates that he lacks the statistical expertise to properly analyze the NASS CDS and to apply sound statistical principles in his analysis and interpretation of his statistical results. His analysis also lacks specificity about the performance of the Dodge Neon and the JCI seatback in rear impacts. As a result, I believe that his attempt to use the NASS CDS to support his opinions about the safety of the Dodge Neon and the JCI seatback in rear impacts is extremely flawed,” her report said.

In her report, Hubele stated that, Viano did not limit his sample to vehicles comparable to the Dodge Neon or those with Johnson Controls seats. Instead, his estimates relied on broad swath of vehicles, ranging from “sporty coupes to large pick-up trucks with bench seating,” in all types of crashes, and all occupants 13 years and older. Then, Viano drilled down into the data until he developed sample sizes of six or fewer. The extremely small sample sizes rendered his conclusions unreliable. Further, she reviewed other Viano papers and found six, published between 2008 and 2010, that all made the same statistical errors.

“The lack of statistical expertise manifest in these problems of using extremely small samples, incorrect statistical analysis procedure resulting in the wrong standard errors, missing data bias and non-standard confidence intervals are repeatedly found in Viano’s publications. Such problems make many of his published results wrong, unreliable, misleading and deceptive,” she wrote in her expert report.

Hubele has challenged Viano’s use of statistics in at least one other case, Neal v. Chrysler. In an August 2006 hearing, Hubele testified as she did in the Heco case that Viano’s statistical analyses used sample sizes too small to be reliable and that his conclusions were not statistically valid. Judge John H. Adams Sr. did not exclude Viano’s testimony, but ruled that he could mention data as a “red flag or almost as an anecdotal information, as a way of being on alert to what’s actually happening out in the real world and then doing subsequent information or subsequent investigation, greater in-depth investigation as to what exactly was going on in these incidents.” He invited the plaintiffs to bring Hubele to the trial, “not necessarily to testify in front of the jury, but to assist me in ruling on the objections that are inevitably going to come.”

At the May hearing to determine how much of Viano’s testimony – if any – would be struck from the trial record, Parenteau appeared in his stead. Gilbert questioned her closely on the motivation for the research she and Viano have done together. She conceded that “most” but not all of it was related to litigation, to be published in Traffic Injury Prevention, and that Viano, Parenteau and another frequent collaborator often cited each other’s papers.

Parenteau testified that they had not yet corrected previous papers analyzing the NASS-CDS data using the wrong methodology and statistical software.

“But usually we do,” she testified. “If we find something, we usually go back.”

Gilbert believes that this admission robs at least some of Viano’s research of its objectivity and authority.

“The big take-away is that people like Viano and his cohorts have made a decision to publish technical articles merely for the purpose of litigation, and then call them peer reviewed, when nothing of the sort happened, because their peers would know that the calculations were wrong. This is not to advance science. It’s to defend litigation,” Gilbert says.

Viano’s Positions on Safe Seat Design

As a research scientist at GM in the 1980s, Viano wrote a paper, later published in 1992, documenting the results of his study of the influence of seat-back angle on occupant retention in a rear impact.  The paper concluded that front seat occupant retention became difficult in rear impacts once the seat back angle rotated rearward more than 45 degrees from vertical and that, at 60 degrees, occupant retention was not possible – even if a seatbelt was worn.

In 1989, GM formed a Seat Safety Task Force to analyze all previous seat litigation against the company and the genesis of GM’s then-existing seat design standards to determine what could be learned about the appropriateness of GM’s approach to seat design. 

In October 1990, Viano sought and received permission to conduct seat design research, arguing that it was needed to determine the biomechanical criteria for seatback strength in rear-end impacts. His tests led him to conclude: “With current [seat] designs the greater the load the greater the seatback deflection, and the greater the potential for occupant ramping up and off the seat.” Viano touted his new High-Retention seat design “a new concept for seatback deflection in rear crashes has been developed and validated in Hyge sled tests.”  In that research, High-Retention Seatback for Safety in Severe Rear-End Crashes, GM Research Laboratories Report, Viano also noted that rear-impacts, although less frequent than frontals, figured prominently in the injury data:

Surprisingly, nearly a quarter of occupant injury occurs in rear-end crashes.  While a majority of the injuries are minor in severity, rear crashes represent an event with relatively high injury rate in comparison to other crash types.…The rates of serious injury and fatality in rear crashes are 62% and 30% respectively of the average crash.  Fatal injuries in rear crashes occur in 0.6/1000 occupants.  This is 30% of the overall fatality rate of 2.0/1000 occupants in all crash types.

Within the documents generated by the Seat Safety Task Force’s work was a group, known as the Litigation Study, which baldly acknowledged that GM had no foundation for its primary defense in litigation.  An April 14, 1992 fax from GM in-house legal counsel Gary Toth to Don Maertens, Chair of GM’s GTC Seat Technical Committee, explained that GM had no legitimate basis for its litigation defense that GM’s seats were designed to yield in a controlled manner.  Buttressing Toth’s observations was a letter from GM engineer Robert E. Hoffman to a GM engineer, V. Cott, at GM Opel in Europe stating that GM did not know how strong to make its seatbacks in order to protect occupants in rear impacts.   

GM initially remained unpersuaded about implementing the proposed new seat design concepts that grew out of Viano’s seat research. In the meantime, plaintiffs’ attorneys used Viano’s work and testimony against GM in lawsuits involving the automaker’s old seat designs.

GM then transferred Viano to Sweden for several years of work on projects unrelated to seats.  When he returned to the U.S. in the late 1990s, he began testifying in defense of GM’s conventional seat designs – despite having found these designs inadequate in his earlier research. Viano’s position was that the older, conventional seat designs were not unsafe, it was simply that the newer seat designs represented a technological advance forward in safety based on his earlier research. Viano also testified that the “yielding” conventional seats were performing quite well in the field. 

Attorney Leon Russell, of the Dallas, Texas Russell Law Firm, who has examined Viano many times in depositions and at trial, says that the debate whether “yielding” or “stiff” seat designs provide the best occupant safety in rear impacts never really existed.

“The only real debate was the fictitious one described in papers and books by defense experts like Viano who then cited to these same publications as proof that a genuine difference of engineering opinion existed about what constituted good seat design” Russell said. “In truth, all vehicle seats yield to a greater or lesser extent in rear impacts and all experts, plaintiff and defense, agree that all seat designs should yield in rear impact.  No expert, plaintiff or defendant, has ever recommended that a car manufacturer should have used a stiff, rigid, un-bending seat. Yet, that’s how Viano has often characterized the supposed choice offered by plaintiff’s experts.  This is particular surprising given that seats meeting or exceeding Viano’s own GM seat strength criteria are often the very types of seats recommended by plaintiff’s experts as safer alternative designs to the weaker “yielding” seats alleged to be defective by design.”  

Johnson Controls Likely to Appeal

The Heco case was among those thrown in the dustbin of the Chrysler bankruptcy. In 2008, U.S. Bankruptcy Court Judge Arthur Gonzalez Monday approved the sale of Chrysler’s assets to Italian automaker Fiat SpA. The automaker had filed for Chapter 11 bankruptcy protection, despite $8 billion in government loans to keep it afloat. The deal allowed Chrysler to rid itself of factories, franchise agreements and other liabilities, such as product defect claims filed by consumers. The terms of the sale specifically foreclosed any then-current or future tort claims against Chrysler for vehicles purchased prior to Fiat assuming control of the company. 

Gilbert says that Viano’s testimony was not meaningful at trial.

“In the end, it didn’t make any difference,” Gilbert said. “This jury rejected Johnston Controls’ evidence. It was absolutely clear. It wasn’t even really close.

The jury Johnson Controls’ motion for a new trial was denied. The company is likely to appeal the verdict.