BRADLEY A. BENSENBERG, Executor of the Estate of DONNA J. BENSENBERG v. Fca Us LLC

In the
United States Court of Appeals
For the Seventh Circuit
No. 20-3407
BRADLEY A. BENSENBERG,
Executor of the Estate of
DONNA J. BENSENBERG,
Plaintiff-Appellant,
v.
FCA US LLC,
Defendant-Appellee.
Appeal from the United States District Court for the
Central District of Illinois.
No. 4:17-cv-04123 — Sara Darrow, Chief Judge.
ARGUED SEPTEMBER 13, 2021 — DECIDED APRIL 8, 2022
Before RIPPLE, ROVNER, and SCUDDER, Circuit Judges.
ROVNER, Circuit Judge. Plaintiff-appellant Bradley
Bensenberg pursues this diversity action on behalf of his
mother’s estate seeking to recover on a claim of strict liability
for injuries she sustained in a one-car accident in which her

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2 No. 20-3407
vehicle’s front airbag did not deploy. The district court granted
a motion in limine to exclude the opinion of Bensenberg’s
expert that the vehicle’s airbag was defective, in that the
vehicle was likely traveling in excess of the deployment
threshold for the airbag when the vehicle struck a concrete post
and came to a halt, and yet the airbag failed to deploy. The
flaw in the expert’s opinion, the court reasoned, was that he
did not identify any purported defect in the vehicle’s airbag
system but simply assumed from the airbag’s failure to deploy
that it must have had a defect of some unspecified type. The
court went on to enter summary judgment in favor of the
defendant. We reverse and remand for further proceedings.
The opinion of the plaintiff’s expert is admissible in order to
show that the vehicle was traveling at a rate of speed sufficient
to command deployment of the front airbag when it collided
with the post. This in turn is sufficient to make a prima facie
case of a non-specific defect in the vehicle’s airbag system
within the parameters that Illinois courts have established for
such a defect.
I.
On September 10, 2015, decedent Donna Bensenberg, age
85, was driving her 2008 Chrysler Aspen (a full-sized sport
utility vehicle) eastbound on Wolf Road, a two-lane highway,
outside of Geneseo, Illinois (about 20 miles east of the Quad
Cities). She lost consciousness as the result of a medical
episode. Her car drifted across the left lane and entered a
grassy ditch running parallel to the highway at a speed that
witnesses (including an Illinois State Police officer) placed at
between 45 and 65 mph. When the car encountered a raised
earthen driveway that crossed the ditch, it became airborne

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No. 20-3407 3
and then returned to ground on the other side of the driveway,
and eventually it came to rest upon striking a small concrete
post. During the incident, the side-curtain airbag deployed
when the vehicle’s sensors detected a potential roll-over, but
the front airbag did not deploy. Ms. Bensenberg was wearing
her seat belt, and the pretensioner (a device designed to pull
the seat belt tight in the event of an accident) deployed
properly. Nonetheless, there are indications that when the
vehicle came to a halt, Ms. Bensenberg’s body came into
contact with the steering wheel and the area of the dashboard
beneath the steering wheel.
As a result of the accident, Ms. Bensenberg suffered an
undisplaced fracture of the second cervical vertebra in her
neck. She wore a cervical collar for three months but did not
require surgery. She died of unrelated causes three years later,
in November 2018.
Ms. Bensenberg filed this suit in 2017 against the car
manufacturer, Fiat Chrysler Automotive or FCA US, formerly
known as Chrysler Group (“Chrysler”), invoking the district
court’s diversity jurisdiction. Following his mother’s death,
Bensenberg stepped into her shoes as the plaintiff in his
capacity as the personal representative of her estate. Counts I
and II of the Fourth Amended Complaint alleged strict liability
claims based on a manufacturing defect and a design defect,
respectively, in the airbag system. Counts III through V alleged
other theories of liability—strict liability for failure to warn,
negligent failure to warn, and negligence—that are not at issue
in this appeal. The estate also pursued claims below that the
seatbelt system was defective, but those claims too are not
raised on appeal.

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4 No. 20-3407
The estate retained as its expert Bahram Ravani, Ph.D., a
Professor in Mechanical Engineering and the Graduate
Program in Forensic Sciences and Engineering at the Univer-
sity of California, Davis. Ravani has substantial experience and
expertise in accident reconstruction, kinematics, and the bio-
mechanical analysis of personal injury accidents. As relevant
here, Ravani opined that, more likely than not, the Chrysler
Aspen was traveling at a rate of speed closer to 53 miles per
hour—the last speed recorded by the vehicle’s event data
recorder (“EDR”) “black box,” which was at or near the
moment when the vehicle’s side airbag deployed—than to five
to 10 miles per hour (which would have been below the front
airbag’s mandatory deployment threshold) when it struck the
concrete post.1 Ravani’s estimate of the vehicle’s likely speed
upon impact thus placed it above the 16 miles per hour must-
deploy threshold for the front airbag. Ravani opined that if
indeed the vehicle was traveling above the deployment
threshold when it struck the post, “then the airbag system was
defective in not deploying the airbag in such a high-energy
impact.” R. 49-5 at 19. The airbag’s failure to deploy, Ravani
further opined, left the driver unprotected “from contact forces
to her body that [we]re the proximal cause of her diagnosed
injuries.” R. 49-5 at 18. But Ravani was unable to identify any
particular component or aspect of the airbag system, including
1 Ravani referenced the range of five to 10 miles per hour because he
assumed that the deployment threshold for the front airbag of the Chrysler
Aspen was roughly 10 miles per hour. R. 42-3 at 98. Defense witnesses,
however, indicated that the must-deploy threshold for the Aspen’s front
airbag was 16 miles per hour, with eight miles per hour representing a
secondary, do-not-deploy threshold. E.g., R. 55-2 at 18.

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No. 20-3407 5
the airbag control unit (“ACU”), that he believed was defec-
tive. (The available data from the vehicle’s airbag monitoring
system revealed no fault in the operation of the airbag system.)
His opinion as to the existence of a defect was instead based
simply on the fact that the airbag did not deploy under
circumstances in which he believed it should have deployed.
On Chrysler’s motion, Judge Darrow excluded Ravani’s
opinion as to the existence of a defect, which she assumed was
a purported defect in the design of the airbag. As the judge
understood Ravani’s reasoning, he surmised from the airbag’s
failure to deploy at a collision speed that he placed above its
mandatory deployment threshold that the airbag must have
been defectively designed; but he did not articulate a theory as
to how the design of the airbag system was defective. R. 60 at
11. The judge did not quarrel with Ravani’s opinion that the
impact of the vehicle likely met the deployment threshold for
the airbag, “but rather with his jump from this premise to the
conclusion that the airbag system was thus defective. Dr.
Ravani offers no evidence to establish how the airbag system’s
design was defective. … He concludes the cause from the
effect.” R. 60 at 10.
The court then proceeded to grant summary judgment in
favor of Chrysler based on the lack of an expert opinion
identifying any purported defect in the airbag system. The
court reasoned that without expert guidance, a layperson
would be unable to evaluate whether the airbag system was
unreasonably dangerous as the result of a defect either in the
design of the system or in the manufacturing process:

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6 No. 20-3407
The … airbag[ ] [is] not [a] simple product[ ].
Although most laymen are familiar with them,
how they work in a general sense, and what they
aim to prevent, most laymen do not know how
they are designed. It is not obvious what …
airbag components are hidden from view, how
… the systems draw information and measure it,
how they are affected by other systems in the
car, the type of events/forces that trigger them to
react, etc. Expert testimony is required to help
the trier of fact determine that an airbag …
system, which [is a] complex product[ ], was
unreasonably dangerous under the consumer
expectations test or the risk-utility test due to a
defective design or manufacturing process.
R. 60 at 19.
II.
Bensenberg has made clear on appeal that he is pursuing a
claim of manufacturing defect and has abandoned any claim of
design defect. His theory is one of a non-specific defect in the
airbag. For that purpose, he relies, as he did below, on expert
opinion to show that his mother’s vehicle was likely traveling
above the mandatory deployment threshold for the front
airbag but that the airbag nonetheless failed to deploy. As a
matter of Illinois law, he believes this evidence supports an
inference that the airbag failed to deploy due to a manufactur-
ing defect. He maintains that the district court erred in exclud-
ing the opinion of his expert as to the existence of such a defect
and in entering summary judgment in favor of Chrysler.

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No. 20-3407 7
The parties agree that in this diversity action we must look
to Illinois law for the substantive legal principles governing
Bensenberg’s claim. See Auto-Owners Ins. Co. v. Websolv
Computing, Inc., 580 F.3d 543, 547 (7th Cir. 2009) (federal court
hearing case in diversity looks to choice-of-law rules of forum
state); Est. of Carey by Carey v. Hy-Temp Mfg., Inc., 929 F.2d 1229,
1232 (7th Cir. 1991) (under Illinois choice-of-law rules, place of
injury supplies governing law unless another state has more
significant relationship to occurrence or parties); Speakers of
Sport, Inc. v. ProServ, Inc., 178 F.3d 862, 864 (7th Cir. 1999) (“The
parties agree that the substantive issues in this diversity suit
are governed by Illinois law, and we do not look behind such
agreements so long as they are reasonable, as this one is.”)
(citing Spinozzi v. ITT Sheraton Corp., 174 F.3d 842, 849 (7th Cir.
1999)); Auto-Owners Ins. Co., 580 F.3d at 547 (same).
A strict liability claim is premised on a defect that renders
a product dangerous because the product fails to perform in
the manner one reasonably expects it to in light of its nature
and intended function. Tweedy v. Wright Ford Sales, Inc., 357
N.E.2d 449, 451 (Ill. 1976); Dunham v. Vaughan & Bushnell Mfg.
Co., 247 N.E.2d 401, 403 (Ill. 1969); Hill v. Int’l Harvester Co., 798
F.2d 256, 258 (7th Cir. 1986) (Illinois law). To prevail on such a
claim, a plaintiff must establish each of the following elements:
(1) a condition of the product resulting from its manufacture or
design, (2) that made the product unreasonably dangerous,
(3) and that existed at the time the product left the defendant’s
control, and (4) an injury to the plaintiff, (5) that was proxi-
mately caused by the condition. Kirk v. Clark Equip. Co., 991
F.3d 865, 878 (7th Cir. 2021) (Illinois law) (citing Clark v. River
Metals Recycling, LLC, 929 F.3d 434, 439 (7th Cir. 2019)); see also

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8 No. 20-3407
Mikolajczyk v. Ford Motor Co., 901 N.E.2d 329, 345 (Ill. 2008). A
product may be unreasonably dangerous as a result of (1) a
manufacturing defect—that is, a physical defect in the individ-
ual product itself, (2) a defect in the product’s design, or (3) the
manufacturer’s failure to warn of a known danger associated
with the product or to instruct the consumer on the proper use
of the product. Mikolajczyk, 901 N.E.2d at 335; Salerno v.
Innovative Surveillance Tech., Inc., 932 N.E.2d 101, 108–10
(Ill. App. Ct. 2010). A “manufacturing defect occurs when one
unit in a product line is defective, whereas a design defect
occurs when the specific unit conforms to the intended design
but the intended design itself renders the product unreason-
ably dangerous.” Id. at 108.
Illinois courts employ two different approaches to deter-
mining whether a product is unreasonably dangerous: the
consumer expectations test and the risk-utility test. Clark, 929
F.3d at 439; Mikolajczyk, 901 N.E.2d at 348. The consumer
expectations test asks whether the product is “dangerous to an
extent beyond that which would be contemplated by the
ordinary consumer who purchases it, with the ordinary
knowledge common to the community as to its characteristics.”
Calles v. Scripto-Tokai Corp., 864 N.E.2d 249, 255 (Ill. 2007)
(quoting Restatement (Second) of Torts § 402A, Comment i, at
352 (1965)). The risk-utility test balances the magnitude of the
danger against the utility of the product, as designed. Id. at 257.
As we have noted, Bensenberg’s theory on appeal is that a
manufacturing defect was responsible for the failure of the
airbag, and he invokes the consumer expectations test as the
appropriate framework to establish that the defect rendered

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No. 20-3407 9
the airbag unreasonably dangerous. In the usual case, expert
testimony is required to establish that a product presents an
unreasonable danger as a result of a defect. See Show v. Ford
Motor Co., 659 F.3d 584, 588 (7th Cir. 2011) (Illinois law); Kirk,
991 F.3d at 878–79; R. 60 at 18. Among the expert’s tasks in
such a case would be to identify the particular defect that gives
rise to the danger. See, e.g., Baltus v. Weaver Div. of Kidde & Co.,
557 N.E.2d 580, 588–90 (Ill. App. Ct. 1990). It was in this regard
that the district court found Ravani’s opinion wanting.
However, Illinois recognizes a claim for non-specific defect,
which, in the appropriate case, relieves the plaintiff of the
obligation to identify a particular defect in the product in order
to make a prima facie case of product liability. Tweedy, 357
N.E.2d at 452; Horne v. Elec. Eel Mfg. Co., 987 F.3d 704, 726 (7th
Cir. 2021) (citing DiCosolo v. Janssen Pharm., Inc., 951 N.E.2d
1238, 1244 (Ill. App. Ct. 2011)); McKenzie v. S K Hand Tool Corp.,
650 N.E.2d 612, 616 (Ill. App. Ct. 1995); Varady v. Guardian Co.,
506 N.E.2d 708, 711–12 (Ill. App. Ct. 1987). The plaintiff may
instead resort to circumstantial evidence that supports an
inference that the product was defective, by showing that the
product failed to perform as expected, in light of its nature and
intended function, and that the product was not being used
abnormally and that there were no reasonable secondary
causes of failure. Tweedy, 357 N.E.2d at 452; Horne, 987 F.3d at
726. This is the framework that Bensenberg references on
appeal.
Bensenberg’s theory that there was a non-specific defect in
the Chrysler’s airbag proceeds as follows: The front airbag was
designed to deploy when the vehicle struck a fixed, non-

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10 No. 20-3407
deformable barrier at an impact speed of at least 16 miles per
hour. When his mother’s vehicle left the roadway and the side
airbag deployed, the vehicle’s EDR indicated that the vehicle
was traveling at a rate of 53 miles per hour. Because the EDR
stopped recording the vehicle’s speed at that point in time,
there is no direct evidence of how fast it was traveling when it
subsequently struck the concrete post. Based on witness
statements and the other available data regarding the accident,
Dr. Ravani opined that when the vehicle struck the post, it was
likely traveling at a rate closer to 53 miles per hour than to five
or 10 miles per hour—in other words, above the 16 miles per
hour mandatory deployment threshold for the front airbag.
R. 49-5 at 16–17. Yet the airbag did not deploy as one would
expect it to have done under these circumstances.
Before we turn to the merits of Bensenberg’s claim, we must
deal with two preliminary objections to the claim as
Bensenberg has framed it on appeal.
Chrysler first contends that Bensenberg waived any theory
of manufacturing defect by not making it below. Based on
Ravani’s deposition, Chrysler understood Bensenberg to be
asserting a claim of design defect only, and the district court’s
order excluding Ravani’s opinion as to the existence of a defect
in the airbag system and granting Chrysler’s motion for
summary judgment indicate that its understanding was the
same. R. 60 at 9, 11.2 However, Bensenberg’s memorandum
2 During Ravani’s deposition, Chrysler’s counsel pressed Ravani on
whether he was truly comfortable asserting that the front airbag malfunc-
tioned, given the airbag monitoring system’s failure to detect any fault in
(continued...)

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No. 20-3407 11
opposing summary judgment indicated that he was pursuing
claims of both design defect and manufacturing defect. R. 49 at
12, 19. No doubt his briefing could have been clearer on this
point, but a close reading of his memorandum leaves no doubt
that he was asserting a claim of manufacturing defect in
addition to a claim of design defect. Bensenberg did not waive
his claim of manufacturing defect.
Chrysler also contends that Bensenberg waived his theory
of non-specific defect and his reliance on Tweedy and its
2 (...continued)
functioning of the airbag and the lack of a dashboard warning light
signaling a problem with the airbag. R. 42-3 at 125–26. In response to
counsel’s questioning, Ravani suggested that the airbag’s failure to deploy
could have been attributable to a problem with the system’s design, i.e., that
the airbag was not designed to deploy under the particular circumstances
of this accident but that it should have been so designed. R. 42-3 at 126–30.
Ravani did not rule out the possibility that the system was not functioning
properly, i.e., that there was a manufacturing defect which prevented it
from operating as designed. R. 42-3 at 130. But in view of the findings of
Chrysler’s experts that the system was functioning properly (which defense
counsel had highlighted in his questioning), Ravani expressed a willingness
to take the defense experts at their word, which would leave only a design
defect as the explanation for the airbag’s failure to deploy. R. 42-13 at 130
(“Now, does that indicate that the air bag did not function? It could. But
your experts have looked at it and they’re saying no, it did not [malfunc-
tion]. The air bag is functioning properly, alright? And I take their word. So
the air bag, assuming it is functioning properly, then the only other option is
that the air bag is not properly designed … .”) (emphasis ours). Reading
Ravani’s remarks in context, we do not understand him to have conceded
away the possibility of a manufacturing defect. In any case, Ravani, as a
witness, was not in a position to formally waive, on the plaintiff’s behalf,
the non-specific manufacturing defect theory that Bensenberg is asserting.

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12 No. 20-3407
progeny (laying out the rationale underlying that theory) by
failing to advance such a theory below. However, in his
memorandum opposing summary judgment and also in his
memorandum opposing the motion to exclude Ravani’s
opinion, Bensenberg employed the language and logic of the
non-specific defect cases and cited authorities discussing non-
specific defects. R. 48 at 11, 20–21 (describing non-specific
defect theory as “malfunction theory”); R. 49 at 21. Again, his
two memoranda could have been clearer on this point, and it
is true that Bensenberg did not cite the seminal Tweedy case in
particular. But it is noteworthy that Chrysler itself cited Tweedy
in replying to Bensenberg on the summary judgment motion.
R. 56 at 6. So there can be no doubt that Chrysler was on notice
that Bensenberg was advancing a non-specific defect theory.
Bensenberg did not waive the theory of a non-specific manu-
facturing defect in the airbag system.
Apart from the waiver issues, Chrysler also argues that the
non-specific defect theory articulated in Tweedy and like cases
is inapplicable here, given the age of Bensenberg’s vehicle and
its substantial degree of use preceding the accident. For
purposes of addressing this argument, it is worth discussing
Tweedy in some detail.
In Tweedy, the brakes failed on a car that had been pur-
chased (used but relatively new) some four months earlier and
had only 7,500 miles on it; the driver suffered injuries as a
result of the incident. Prior repairs had been made to the
vehicle, but not to the brakes. The plaintiff pursued a claim of
strict liability, but produced no expert testimony identifying
any particular defect in the brake system of the vehicle. The
Illinois Supreme Court nonetheless concluded that a factfinder

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No. 20-3407 13
could infer the existence of such a defect from the failure of the
brakes to work as expected:
Here the evidence shows that the brakes of an
automobile driven approximately 7,500 miles,
inspected … prior to delivery, inspected again at
6,000 miles, and subjected to no abnormal use
prior to the occurrence failed to function in the
manner reasonably to be expected. Plaintiff was
driving carefully at a reasonable rate of speed,
the weather was good, the roads were dry, he
knew the intersection well, and there was no
evidence of any reasonable secondary cause.
357 N.E.2d at 452. Consequently, it was reasonable to infer that
the vehicle’s brakes must have been defective at the time that
they left the seller’s control and expert testimony was not
required in order to make out a prima facie case of a product
defect. See id. at 451–52.
As Chrysler points out, subsequent cases have distin-
guished Tweedy when the product at issue is older, has been
subject to extensive use, and there are other apparent potential
secondary causes of failure apart from a defect in the design or
manufacture of the product that cannot be ruled out. See, e.g.,
Bielskis v. Louisville Ladder, Inc., 663 F.3d 887, 899 (7th Cir. 2011)
(distinguishing Tweedy on ground that allegedly defective
scaffold had been in use and subject to normal wear and tear
for a period of seven years and plaintiff had produced no
evidence as to condition of scaffold when it came into his
possession).

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14 No. 20-3407
The vehicle at issue here was anything but new. Bensenberg
had purchased the Chrysler Aspen used in 2009 with about
27,000 miles already on the odometer. By the time of the
accident some six years later, the vehicle had accrued a total of
roughly 128,000 miles and had been serviced and repaired
repeatedly. On its face, this case would appear to be a far cry
from the scenario at issue in Tweedy.
But given the particular vehicular component at issue here,
we are not convinced that Bensenberg was necessarily pre-
cluded from relying on Tweedy’s articulation of the non-specific
defect theory. Chrysler’s argument in this respect presumes
that the reliability and efficacy of all vehicular components
decline with time and usage of the vehicle, as is the case with
brakes or tire treads, for example. But airbags are only used
when deployed. Replacement will obviously be required
following deployment, but otherwise, nothing in this record
suggests that the lifespan of a modern airbag is shorter than
the seven to eight years this vehicle was in use prior to the
accident. See Ronald Montoya, Do car airbags expire?, EDMUNDS
(Mar. 29, 2013), https://www.edmunds.com/car-safety/
do-car-airbags-expire.html (visited April 4, 2022) (noting
modern technology enables airbags to last for life of vehicle);
cf. Owner’s Manual, 2008 Chrysler Aspen, at 61 (noting that
“the airbag system is designed to be maintenance free”),
available at https://carmanuals2.com/get/chrysler-aspen-2008-
owner-s-manual-31277 (visited April 4, 2022). As Chrysler has
emphasized in this litigation, vehicles including this one are
equipped with a monitoring system that will alert the driver if
there is a problem with the supplemental restraint system.
Moreover, as the plaintiff points out, airbags are contained

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No. 20-3407 15
within the vehicle in such a way that makes tampering,
modification, or inadvertent damage to the airbags difficult.
There is no indication in the record that the airbags in this
particular vehicle ever deployed, such that replacement was
required, nor is there any indication the vehicle’s electronic
monitoring system alerted Ms. Bensenberg to a potential
malfunction or a need to service or replace the airbag system.3
On these facts, assuming the admissibility of Ravani’s opinion
as to the likely speed of Ms. Bensenberg’s vehicle at the time of
impact, a jury could find that, notwithstanding the age,
mileage, usage, and repair history of the vehicle, Ms.
Bensenberg could reasonably expect the front airbag to deploy
if her vehicle struck an immovable object at a rate of speed in
excess of the airbag’s deployment threshold.
A further word is in order here about Ravani’s opinion and
its relationship to Bensenberg’s claim. In assessing the admissi-
bility of Ravani’s opinion under Daubert v. Merrell Dow Pharm.,
Inc., 509 U.S. 579, 113 S. Ct. 2786 (1993), the district court
labored under the impression that Ravani was obliged to
3 Our understanding of the deposition testimony of Emanuel Goodman,
who worked for ZF Friedrichshafen AG (formerly TRW Automotive),
which manufactures airbag control units and sensors, is that the data
downloaded from the Chrysler Aspen’s ACU reflects a relatively compre-
hensive history of the vehicle’s airbag system, including faults. See R. 42-5
at 7–11, Goodman Dep. at 22–41. The data indicated that there were prior
fault warnings for the airbag system, but not at the time of the accident. We
may therefore assume that neither the prior ownership and use of the
vehicle by someone other than Ms. Bensenberg nor her own extensive use
of the vehicle cast doubt on the functionality of the airbag system, and that
had there been a problem with the system at the time of the accident, the
ACU data would have reflected it.

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16 No. 20-3407
identify a specific defect in the airbag system. She therefore
viewed as ipse dixit his conclusion that the airbag system was
defective because the front airbag did not deploy notwith-
standing the collision with the concrete post at a speed above
the deployment threshold for that airbag. R. 20 at 6, 10, 11. But
this misapprehends the nature of Bensenberg’s theory of the
case. Because Bensenberg is pursuing a claim of non-specific
defect, he is not obliged to identify a particular defect in the
airbag system and nor was Ravani’s opinion rendered inadmis-
sible because he did not identify such a defect. In this regard,
the district court erred in excluding his opinion as to the
existence of a defect. Again, the district court’s failure to
appreciate the nature of the theory that Bensenberg was
pursuing may well have been due to the lack of clarity in his
briefing. But for the reasons we have set out above, we are
satisfied that Bensenberg did enough to preserve the theory of
non-specific manufacturing defect that he presses on appeal.
This is not to say that expert testimony was not required to
support Bensenberg’s theory of the case. The premise of
Bensenberg’s claim of non-specific defect, after all, is that the
vehicle struck the concrete post while traveling at a speed in
excess of the front airbag’s deployment threshold. There is no
direct evidence of the vehicle’s speed at the moment of impact.
The vehicle’s EDR stopped recording the SUV’s speed when
the vehicle became airborne after striking the earthen driveway
crossing the ditch. And Ms. Bensenberg herself had lost
consciousness. Consequently, the vehicle’s likely speed must
be deduced from what information is available from the
vehicle’s EDR, witnesses to the incident, and the damage to the
vehicle, among other sources. This is not the sort of determina-

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No. 20-3407 17
tion that the ordinary layperson would have the capability to
make for himself; it calls for expertise in accident reconstruc-
tion. Toward that end, both parties offered expert opinion as to
the likely speed of the SUV at the moment of impact.
There is no real dispute that Ravani was qualified to render
an opinion as to the vehicle’s likely speed at impact. Given the
ground on which the district court excluded Ravani’s opinion,
it was not necessary for the district court itself to reach the
matter of Ravani’s qualifications.4 But the record makes plain
that Ravani has extensive experience and expertise in accident
reconstruction, such that he is qualified to render an opinion
on this point. Chrysler itself raises no question about Ravani’s
expertise in this regard. See R. 42 at 4; R. 55 at 1; R. 20 at 8 n.4.
Its focus instead is whether Ravani’s opinion is admissible
absent him being able to identify a specific defect in the airbag
system, and we have resolved that point in Bensenberg’s favor.
Nor, for purposes of this appeal, do we discern any obvious
fault with Ravani’s methodology. Ravani appears to have
taken the same general approach to estimating the vehicle’s
speed at impact as the defendant’s expert, Matthew Weber:
that is, he looked to the evidence bearing on the vehicle’s path
of travel, the available data regarding the vehicle’s speed at the
moment it became airborne, the distance the vehicle traveled
when it returned to the ground, and the clues offered from the
damage that the vehicle incurred as a result of the collision. R.
55-2. The two experts obviously reached different conclusions:
4 Bensenberg contends that this was an error on the court’s part, but we
disagree: the court could rightly assume his qualifications but find his
opinion inadmissible on an unrelated ground.

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18 No. 20-3407
Weber opined that the vehicle was traveling below the airbag
deployment threshold when it struck the post. R. 55-2 at 18.
But Chrysler points to no flaw in Ravani’s methodology that
would render his opinion inadmissible or that would preclude
the facfinder from relying on it. See R. 20 at 9 (“Defendant has
not argued that these methods were unlikely to produce a
reliable estimate of the Aspen’s speed at final impact.”).5
Indeed, as we have already mentioned, the district court itself
had no quarrel with the admissibility of Ravani’s opinion that
the vehicle was likely traveling above the airbag deployment
threshold at the moment of impact, which was the very
purpose for which plaintiff offered his opinion. R. 20 at 10.
What remains, then, is whether Bensenberg has presented
enough evidence to make out a prima facie case of strict
liability for a manufacturing defect, within Illinois’ framework
for a claim of non-specific defect. On the limited record and
arguments presented to us on this point, we conclude that he
has. Again, Bensenberg’s theory is that under the circum-
stances of this accident, the vehicle collided with an immovable
object, the concrete post, while traveling at a rate of speed
above the airbag’s must-deploy threshold. Ravani’s opinion
was offered to establish the vehicle’s likely speed on impact,
and he concluded that the vehicle more likely than not was
traveling closer to 53 miles per hour (the last recorded speed
5 Chrysler has argued that Ravani was wrong to rely on the state police
officer’s observations as to the path and distance the vehicle traveled after
leaving the roadway in making estimates as to the vehicle’s likely speed
when it impacted the post. But, in context, we view this as an objection to
the weight that the factfinder should give to Ravani’s opinion rather than
a potentially disqualifying objection to his expertise and methodology.

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No. 20-3407 19
on the vehicle’s EDR) than to five to 10 miles per hour. If
credited, that opinion tends to rule out the most obvious and
likely secondary explanation for the airbag’s failure to deploy:
that the vehicle’s speed when it struck the concrete post was
below the airbag’s deployment threshold. And given the data
from the vehicle’s ACU indicating that the airbag system was
functioning properly at the time of the accident, a factfinder
could infer the airbag had not been subject to abuse or tamper-
ing that might interfere with its operation. This in turn would
permit an inference that there was a non-specific defect in the
vehicle’s airbag system that accounts for the front airbag’s
failure to deploy.
On this record, then, there is a fact question that precludes
summary judgment in favor of Chrysler.
III.
The judgment is reversed, and the case is remanded for
further proceedings consistent with this decision.

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