Carl F. Thelin

SILKY

In a 1988 model Chevrolet Cavalier Ms. Jane Silky was a passenger when the car crashed. She injured her head when she hit the passenger side instrument panel. We contended, in this case, that the window shade “comfort enhancement” feature of the shoulder belt for the right front passenger caused the injury to be much more severe than it would have been had the vehicle used a conventional lap and shoulder belt that would remain snug at all times.

Beginning in 1976, many domestic automobiles adopted a feature that automatically relieved the tension of the shoulder belt. It was nicknamed the "window shade" retractor. The designers of the shoulder belt retractors expected this retractor to produce slackness in the portion of the belt which restrains the upper torso. After the occupant put the belt around her torso and snapped the belt latch plate into the buckle at the side, the torso belt may be uncomfortably tight, pulling down on the shoulder, and across the chest. Many women expressed that opinion one way or another to domestic car manufacturers. To relieve this tension on the shoulder, the designer added a window shade ratchet mechanism to the belt retractor to provide slack in the belt automatically. After buckling, the occupant could pull the shoulder belt away from her chest, and then allow it to retract slowly until the window shade ratchet engaged. Then the strap draped comfortably on the shoulder and between her breasts. She was expected to periodically remove excessive slack by pulling out on the belt and allowing it to snap back.

Lawyers asked me about the history of the use of the window shade feature. Without going back to old records, I recall that they first appeared around 1976 and did not begin to phase out until almost ten years later. I had a multi-page table showing the data from many issues of CONSUMER RE¬PORTS. One column shows a ‘Y’ when I know that the tested vehicle used the window shade. The comments often quote the description of the problem that arose when the window shade was present in the tested model. Note that these criticisms apply to General Motors, Ford and Chrysler products – all cars made in North America.

The window shade feature was the object of many design-defect lawsuits over the years. I believe that the cost of the lawsuits - whether won or lost - persuaded GM, Ford and Chrysler to abandon the windows shade feature. Finally giving in to the demands of consumer advocates, they began to install airbags for both front seat positions with conventional lap and shoulder belts.

When the feature was introduced, the National Highway Traffic Safety Administration (NHTSA) went along with the industry’s initial argument that the window shade comfort enhancement feature would result in increased usage -- enough to overcome the loss of performance resulting from a small amount of shoulder belt slack. Note also, that GM continued to try to avoid the requirement to provide front seat airbags by installing the so-called automatic seat belt system that attached both the lap and shoulder belts to the front door frames. Even though many safety proponents criticized this design because of the hazard it created, the domestic industry continued to use it, contending that the usage rate of seat belts increased because of the comfort enhancing feature of slack. They claimed that greater usage compensated for the reduction of restraint performance. One could not contest this argument in those days when the observed usage rate for seatbelts was about 10 percent. Then, very few people crashed while using any seatbelt, so we saw few opportunities to note those belts that failed to perform well. No car designed in Europe or Japan ever used the slack producing retractor, to my knowledge.

The Cavalier model Chevrolets continued using a window shade shoulder belt until the all-new 1995 model year Cavalier adopted a dual airbag system with conventional seat belts. By the way, notice that the 1987 model Pontiac Le Mans did NOT use the window shade, even though it was a GM car smaller than the Cavalier was. This is because GM’s Opel ‘division’ in Germany designed that car for Pontiac. Then General Motors had Daewoo Motors in South Korea manufacture the Lemans economy car for the Pontiac Division. It was a badly needed replace¬ment for the awful Pontiac T100 version of the Chevette small car. GM chose to leave the belt system as Opel designed it rather than spend the money on that low production vehicle to revise it to US standards with the window shade retractors.

Many evaluators wrote that the window shade mechanism was often too sensitive, and allowed two or three inches of slack to develop when the normal ride jiggling motions of the occupant caused small increments of the window shade ratchet effect. I said that myself when writing for CONSUMER REPORTS magazine. I said that excessive slack in the torso belt is hazardous. Slack in the shoulder belt increased the distance which the passenger’s chest snaps forward before the belt begins to restrain her. The belt retractor locked when the crash began. Then the impact of the fast moving torso catching up with the belt causes a snap which produced high forces on the woman’s chest, and on the belt. When enough slack is present in a severe crash, that snap could break the shoulder belt or pull the D ring bolt out of the top of the B pillar. That did not happen this time.

Another problem exists when the crash is not aligned directly against the front of the vehicle. For instance see what will happen when a collision occurs on the right front corner. In engineering (CxSI) terms, that means that the impact force is coming from 1 or 2 o’clock. The forensic term is Principle Direction of Force (PDOF).This typically happens when “our” car is struck by an opposing vehicle when our driver attempts to make a left turn without allowing enough time to get all the way out of the path.

Everything within the struck car while move toward the PDOF. The driver’s upper torso may slip entirely out of the shoulder belt so that he will move toward the center front of the car. The slack belt has already loose over the side of the driver’s left shoulder. Thus, his upper torso would move freely away from the upper part of the belt. The lap belt, the lower part of the upper belt, would bear against the abdomen producing the same sort of injuries one sees when the occupant submarines under a lap belt. The lap belt alone does not limit excursion of the head but may make it worse by causing the head to swing down face first into the instrument panel near the center of the car..

The same sort of thing happens when the point of a different collision is at the left front corner with a PDOF of 10 or 11 o’clock. In this case, the front passenger slides out of the shoulder strap toward the cluster of hardware in the center stack.

What follows are parts of my report to the lawyer who represented Ms. Silky. This case did not get to the point or depositions or trial.

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REPORT OF POSSIBLE EXPERT TESTIMONY
Background of the Incident:
On May 12, 1999, CSI, Incorporated began to investigate the collision that occurred June 13, 1998. The collision occurred on Alabama Highway 119, a two-lane road. A northbound 1989 Chevrolet two-door Cavalier, driven by Mr. (her boy friend), struck a southbound 1995 Ford van that turned left across the path of the Cavalier. Ms. Jane Silky was the passenger on the right front seat of the Cavalier. She received severe internal and external injuries, including severe head trauma, despite having worn the available lap and shoulder belt.

General Conclusions:
It is my technical opinion with a reasonable degree of engineering certainty, based on the evidence available to me, that this vehicle contains a seat belt system with a dangerous defect. That defect is the incorporation of a tension reliever feature in the seat belt retractor. This device allows excessive slack to build up in the shoulder belt without the knowledge of the wearer. During the crash, this excessive slack allowed the upper torso of Ms. Silky to strike the instrument panel with great force, causing severe injuries. In addition, the absence of upper torso restraint allowed Ms. Silky to double over the lap belt and receive serious injuries to her lower torso.
I. Opinions: Basis and Reasons Therefore. At trial, I will be prepared to testify to the following general opinions:
(1) The seatbelt restraint system which includes the “window-shade” feature is defective and unreasonably dangerous. The window-shade feature encourages the inadvertent - that is, unknown to the user - build-up of excessive slack. Documentary and anecdotal evidence clearly show that the design of the window-shade feature is defective and unreasonably dangerous. Documents produced by GM in this litigation prove that GM was aware of the fact that slack develops as a result of the window shade feature and that the buildup of such slack is oftentimes unknown to the user. Although GM was willing, it appears from the documents produced in this litigation, to allow a certain amount of slack to build up between the seatbelt user and the seatbelt, the documentary evidence shows that amounts of slack buildup are even in excess to the amounts considered acceptable to GM.

The evidence gleaned form the documents produced by GM also proves that at the time they produced and placed into the stream of commerce, GM was aware that the excessive slack buildup was often inadvertent and unknown to the user. A November 3, 1976, letter from E.H. Mertz, a GM Chief Engineer, contains numerous examples of the excessive slack and inadvertence issues that were available to GM. The list of GM personnel who received the letter includes most of the people responsible for automotive safety at GM at that time. Such evidence strongly and conclusively proves that GM, at numerous levels, was aware of the design defects inherent in the window shade retractor feature. Contrary to arguments made by GM in other similar litigation to the effect that comfort seatbelt designs, such as the one involved in this litigation, tend to increase significantly seatbelt usage among the population, a paper presented by Mr. David Biss at a convention in Goteborg, Sweden held May 29 through June 1, 1989 contains multitudinous evidence that this is simply not the case. GM produced this document. It has this identification: CF 1646-1681.

(2) In the year in which the car left the control of General Motors, alternative feasible designs were available to General Motors which would have been safer than the defective seatbelt restraint system that General Motors chose to use. General Motors easily could have used any number of these alternative designs. Feasible designs would have included those seat belts systems that GM used in vehicles produced for sale in Europe and Japan. Those seatbelt systems were generally one-piece, continuous-loop, lap-shoulder belts with a lightweight free sliding latch plate. The lightweight latch plate would have required less tension from the shoulder belt retractor to pull the seat belt and retractor out of the open doorway. This system would, of course, apply a light tension to the belt when worn.

Additional feasible alternatives could have included, but would not have been limited to, those referred to by GM itself in a presentation given by Bob Sinke on February 20, 1987 (See CF(C) GTC 8702200035).

(3) Ms. Silky was wearing the lap and shoulder portions of her seatbelt. During the accident, Ms. Silky was restrained primarily by the lap portion of the seatbelt. There is an obvious mark on the seatbelt that confirms this. In addition, her severe abdominal/intestinal injuries are consistent with the known effects of restraint of front-seat passengers solely with lap belts. The shoulder portion of the seatbelt did not restrain her well. This allowed her head to contact the dashboard and caused her to suffer injuries consistent with the so-called “jackknife” effect; i.e., the abdominal/intestinal injuries referenced immediately above. We saw no physical evidence that the seatbelt did bear any load on the shoulder portion of the belt. Ms. Silky sustained no bruises or other injuries suggestive of any such loading.

I inspected the subject vehicle and the driver and front passenger seatbelts. The front passenger seatbelt in use at the time of the accident was a replacement part authorized and approved by GM and was the same design and type of seatbelt that originally installed on the automobile. I compared the marks found on the driver’s belt webbing with that of the passenger belt.

This vehicle has a chrome-plated D-ring which is the device at the top of the B-pillar behind the door. Unlike the more-common D-ring, covered with black plastic, a chrome-plated D-ring cannot transfer any abraded plastic onto the webbing. We found some lightly polished sections of the shoulder belt webbing. This was at the position where the D-ring would be when the belt was worn. Nevertheless, there was no indication of heavy loading on the upper section of the belt. This vehicle also has the older model tilt-lock latch plate. Unlike the newer lightweight versions, this one is all metal. It cannot transfer black plastic onto the belt strap, either. Nevertheless, I did find an intense compression type mark on the webbing. It was narrow, as one would expect from the edge of the lock bar in the latch plate. It was at the position one would expect it to be. Even if the shoulder belt was fully extended, thus offering no protection, the latch plate would hold the lower part of the webbing secure.

(4) The injuries to Ms. Silky are consistent with the injuries a person would receive if involved in a collision of the sort described in the police accident report and eye-witness accounts and in which she was restrained tightly by a lap belt but with no restraint from a shoulder belt. Being restrained by a lap belt with little or no restraint from a shoulder belt is associated with increased risk of injuries.

The dangers associated with using a lap/shoulder belt in which the lap belt portion operates appropriately and the shoulder portion of the belt does not are well-documented. National Transportation Safety Board document PB86-917006 is just one of many documents which describe such dangers. This July 1986, document tracks the performance of lap belts in 26 frontal collisions.

(5) Because she was wearing a defective and unreasonably dangerous seatbelt restraint system, which did not adequately restrain her upper body, Ms. Silky received greater injuries than she might have suffered had she been properly restrained.

The pattern of injuries to Ms. Silky injuries is consistent with the above description. Due to the defective design of the seatbelt, her upper torso was free to pivot forward and down, and slightly to her left, striking the instrument panel with great force. The lap belt, which was the only portion of the belt to perform, caused characteristic injuries to her lower torso due to the lack of restraint of her upper torso.

II. Data or Other Information Considered in Forming Opinions
(1) Deposition of Jane Silky;
(2) Medical records of Jane Silky;
(3) Affidavit of (her boy friend, the driver), the driver
…
(14) European, Japanese, and Australian Motor Safety Standards regarding proper seatbelt restraint systems;
(15) Crash tests and test car experiences I had while working as the automobile safety engineer for the Consumer’s Union (1972-81), and as an Auto Safety Consultant since then;
(16) Automobile test reports in Consumer Reports which criticize the window shade seat belt retractors, including those that I wrote, from 1976 on;
(17) My personal experiences, including my training, education, and employment as summarized in my curriculum vita attached hereto.

In addition, I expect to review the testimony, whether by deposition or otherwise, of any corporate representatives for General Motors, any testimony given or proposed by experts on behalf of General Motors, and any additional paper discovery. …
III. Exhibits
(1) Any or all of the above-listed items might serve as exhibits to or summaries of my testimony;
(2) Prior to trial, we expect to create a demonstration of the process of slack build-up in the seatbelt restraint system with the “window-shade” feature used by General Motors;
(3) An exemplar vehicle;
(4) The actual vehicle and seatbelt involved in Ms. Silky’ injuries;
…
(18) A video that I have of sled tests involving different levels of restraint for a driver;
(19) Films and/or videos of sled tests made by David Biss showing the performance of a passenger seatbelt restraint system with varying degrees of slack introduced;
(20) A mock seatbelt restraint system using the same lap and shoulder belt and window shade design as is made the basis of this lawsuit;
(21) Example clippings of automobile test reports in Consumer Reports that criticize the window shade seat belt retractors, including those that I wrote, from 1976 on.

I expect, potentially, to use any or all of the above-listed as exhibits in support of my opinions. At this time, I have not prepared specific demonstrative exhibits (such as charts, graphs, or time-lines, etc.), but prior to trial I will prepare certain demonstrative aids to help illustrate my testimony. I do not expect to be able to make a determination of what sort of demonstrative evidence I might need to create until more discovery has been done in the case and until I can better see what facts and opinions are in dispute.
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That is the end of the report (and this story)