                United States Court of Appeals
                           For the Eighth Circuit
                       ___________________________

                               No. 15-2507
                       ___________________________

                               Jassmine D. Adams

                       lllllllllllllllllllll Plaintiff - Appellee

 State of Minnesota, Department of Human Services; UCare Minnesota; Medica
                                 Health Plans

                lllllllllllllllllllllIntervenor Plaintiffs - Appellees

                                          v.

Toyota Motor Corporation; Toyota Motor Sales, U.S.A., Inc.; Toyota Motor North
America, Inc.; Toyota Motor Engineering and Manufacturing North America, Inc.;
   Toyota Motor Manufacturing, Kentucky, Inc.; Calty Design Research, Inc.

                    lllllllllllllllllllll Defendants - Appellants
                        ___________________________

                               No. 15-2516
                       ___________________________

                                Quincy Ray Adams

                       lllllllllllllllllllll Plaintiff - Appellee

 State of Minnesota, Department of Human Services; UCare Minnesota; Medica
                                 Health Plans

                lllllllllllllllllllllIntervenor Plaintiffs - Appellees

                                          v.
Toyota Motor Corporation; Toyota Motor Sales, U.S.A., Inc.; Toyota Motor North
America, Inc.; Toyota Motor Engineering and Manufacturing North America, Inc.;
   Toyota Motor Manufacturing, Kentucky, Inc.; Calty Design Research, Inc.

                     lllllllllllllllllllll Defendants - Appellants
                         ___________________________

                                No. 15-2635
                        ___________________________

                                Jassmine D. Adams

                       lllllllllllllllllllll Plaintiff - Appellant

 State of Minnesota, Department of Human Services; UCare Minnesota; Medica
                                 Health Plans

                       lllllllllllllllllllllIntervenor Plaintiffs

                                           v.

Toyota Motor Corporation; Toyota Motor Sales, U.S.A., Inc.; Toyota Motor North
America, Inc.; Toyota Motor Engineering and Manufacturing North America, Inc.;
   Toyota Motor Manufacturing, Kentucky, Inc.; Calty Design Research, Inc.

                     lllllllllllllllllllll Defendants - Appellees
                        ___________________________

                                No. 15-2636
                        ___________________________

Bridgette Trice, as trustee for the heirs and next of kin of Devyn Bolton, deceased

                       lllllllllllllllllllll Plaintiff - Appellant

Koua Fong Lee; Nhia Koua Lee; Nong Lee; Panghoua Moua; Jemee Lee, a minor
 child; American Family Mutual Insurance Company, as subrogee of Koua Fong
  Lee; State of Minnesota, Department of Human Services; UCare Minnesota;
                                Medica Health Plans

                        lllllllllllllllllllllIntervenor Plaintiffs

                                            v.

Toyota Motor Corporation; Toyota Motor Sales, U.S.A., Inc.; Toyota Motor North
America, Inc.; Toyota Motor Engineering and Manufacturing North America, Inc.;
   Toyota Motor Manufacturing, Kentucky, Inc.; Calty Design Research, Inc.

                      lllllllllllllllllllll Defendants - Appellees
                         ___________________________

                                 No. 15-2637
                         ___________________________

Bridgette Trice, as trustee for the heirs and next of kin of Devyn Bolton, deceased

                              lllllllllllllllllllll Plaintiff

Koua Fong Lee; Nhia Koua Lee; Nong Lee; Panghoua Moua; Jemee Lee, a minor child

                 lllllllllllllllllllllIntervenor Plaintiffs - Appellants

 American Family Mutual Insurance Company, as subrogee of Koua Fong Lee;
 State of Minnesota, Department of Human Services; UCare Minnesota; Medica
                                 Health Plans

                        lllllllllllllllllllllIntervenor Plaintiffs

                                            v.

Toyota Motor Corporation; Toyota Motor Sales, U.S.A., Inc.; Toyota Motor North
America, Inc.; Toyota Motor Engineering and Manufacturing North America, Inc.;
   Toyota Motor Manufacturing, Kentucky, Inc.; Calty Design Research, Inc.

                      lllllllllllllllllllll Defendants - Appellees
                        ___________________________

                                No. 15-2638
                        ___________________________

                                 Quincy Ray Adams

                        lllllllllllllllllllll Plaintiff - Appellant

 State of Minnesota, Department of Human Services; UCare Minnesota; Medica
                                 Health Plans

                        lllllllllllllllllllllIntervenor Plaintiffs

                                            v.

Toyota Motor Corporation; Toyota Motor Sales, U.S.A., Inc.; Toyota Motor North
America, Inc.; Toyota Motor Engineering and Manufacturing North America, Inc.;
   Toyota Motor Manufacturing, Kentucky, Inc.; Calty Design Research, Inc.

                     lllllllllllllllllllll Defendants - Appellees
                                      ____________

                   Appeals from United States District Court
                   for the District of Minnesota - Minneapolis
                                  ____________

                             Submitted: August 1, 2017
                              Filed: August 11, 2017
                                  ____________

Before LOKEN, MURPHY, and KELLY, Circuit Judges.
                          ____________

KELLY, Circuit Judge.

       On June 10, 2006, Koua Fong Lee was driving his 1996 Toyota Camry on the
interstate. When Lee exited the interstate, the Camry failed to come to a stop and
rear-ended another car waiting at a stoplight, killing three of the other car’s five
passengers and injuring others, including those in Lee’s vehicle. Lee was convicted
of vehicular homicide, but his conviction was vacated after Toyota recalled several
models of their Camry for issues related to unintended acceleration, ultimately
leading to new evidence in Lee’s case.

        Family members of the deceased filed a lawsuit against Toyota in state court
in 2010, alleging, among other things, personal injury and wrongful death based on
strict product liability, and Lee eventually joined as a plaintiff. Following a four-
week trial, a jury found Lee 40 percent and Toyota 60 percent at fault for the
collision. The district court entered judgment on June 25, 2015. Having jurisdiction
under 28 U.S.C. § 1291, we affirm in part and reverse in part.

                                  I. Background

       In June 2006, after attending several family events in Minneapolis, Lee was
driving his 1996 Toyota Camry eastbound on the interstate from Minneapolis toward
St. Paul with his pregnant wife, their young daughter, his father, and his brother. He
was going around 65 miles per hour. He exited the interstate at the Snelling Avenue
ramp, which had a slight incline leading up to an intersection. Lee testified that he
pressed on the accelerator as he went up the ramp and pushed on the brake at the top
of the incline, approximately 600 feet from the intersection.

       Lee and his passengers explained that as Lee approached the intersection, he
pumped the brakes and yelled that they were not working. The Camry was going
approximately 75 miles per hour when it rear-ended an Oldsmobile Ciera that was
waiting at a red light, pushing the Oldsmobile into oncoming traffic. The
Oldsmobile’s driver, Javis Trice-Adams, and Trice-Adams’ six-year-old son, Javis
Jr., died at the scene of the collision. Quincy Adams, Trice-Adams’ father, was
seated in the front passenger seat and suffered a traumatic brain injury. Trice-Adams’

                                         -5-
niece, six-year-old Devyn Bolton, was seated in the middle of the back seat. Upon
impact, she ceased breathing and her heart stopped beating. Paramedics revived her
in the ambulance, though she stayed in a coma for a period of weeks. Devyn was
rendered quadriplegic, and though she was able to fully regain her mental faculties,
she died from respiratory complications arising from her quadriplegia approximately
a year after the accident. Finally, Jassmine Adams, Trice-Adams’ thirteen-year-old
daughter, was seated in the back passenger seat of the car. Her leg was crushed by
the impact, but she survived. Occupants of Lee’s car were also injured, but all
survived. In 2007, Lee was charged with vehicular homicide. Though he alleged at
trial that the Camry’s brakes were not working, he was convicted and sentenced to
eight years in prison.

      In 2010, Toyota recalled several models of their Camry—not including the
1996 Camry Lee was driving at the time of the accident—for issues related to
unintended acceleration.1 Lee filed a petition for post-conviction relief in state court
based on new information about instances of unintended acceleration in 1995 and
1996 Camrys, and his conviction was ultimately vacated. Prosecutors did not appeal
or pursue additional criminal charges, and Lee was released after being incarcerated
for over two years.

      Family members of the deceased filed this product liability lawsuit against
Toyota in state court in 2010, alleging that a defect in Lee’s Camry’s acceleration
system led to the collision and resultant injuries. Lee eventually joined as a plaintiff.
Toyota removed the case to federal court. Prior to trial, the district court ruled on a
number of motions, including Toyota’s motion to exclude evidence of other similar
instances of unintended acceleration (OSIs) and Toyota’s motion to exclude the



      1
       Because Lee’s 1996 Camry was not included in the recall, the jury was
instructed not to consider the recalls for any purpose.

                                          -6-
testimony of the plaintiffs’ mechanical engineering expert, John Stilson.2 The court
allowed the plaintiffs to present OSI evidence, but required the plaintiffs to reduce
their proposed witnesses to “a list of a much smaller number . . . whose testimony is
most similar,” ultimately limiting the plaintiffs to three OSI witnesses. Each OSI
witness testified that he was driving a 1996 Toyota Camry with over 100,000 miles
on it when he experienced at least one incident of unintended acceleration.

       The court denied the motion to exclude the plaintiffs’ expert. At trial, the
plaintiffs’ expert, Stilson, explained the relevant parts of a 1996 Camry’s engine,
focusing specifically on the components of the accelerator control system—which
included the throttle—and the cruise control system. Though both systems were
housed within the same plastic dust cover, Stilson testified that the cruise control
system was mechanically separate from the accelerator control system. Stilson opined
that the accelerator control system was defective. He conducted testing which
revealed that, when heated to a certain temperature, two of the throttle pulleys in the
accelerator control system would bind together and cause the throttle to stick. In
order to conduct these tests, he explained, he had to clip the cruise control arm away
from its original factory position. Stilson ultimately concluded that the plastic dust
cover had gaps allowing heat to enter and become trapped inside, causing the plastic
throttle pulleys to overheat and stick together. In Stilson’s opinion, this sticking
defect led to the unintended acceleration, and ultimately to the collision in this case.

       Prior to the verdict, Toyota moved for judgment as a matter of law (JAML),
arguing that the evidence was insufficient to prove a design defect and causation.
Toyota also reiterated its arguments about the inadmissibility of the OSI evidence and
Stilson’s testimony in post-trial motions, which the district court denied. The jury
returned a $14 million verdict in favor of the plaintiffs, though the court reduced the


      2
        The district court also granted partial summary judgment for Toyota on several
issues, none of which is challenged in this appeal.

                                          -7-
monetary award to plaintiff Bridgette Trice, Devyn Bolton’s mother, based on a prior
settlement. Judgment was entered in June 2015. Toyota timely appealed and Trice
cross-appealed.

      On appeal, Toyota argues that the district court erred in (1) admitting the OSI
evidence, (2) admitting Stilson’s expert testimony, (3) denying Toyota’s motion for
JAML, and (4) awarding plaintiff Trice prejudgment interest. On cross-appeal, Trice
argues that the district court erred in reducing her monetary award.

                                    II. Discussion

A.    OSI Evidence

       Toyota argues that the district court erred by allowing the plaintiffs to present
evidence of allegedly similar incidents experienced by other 1996 Toyota Camry
drivers. “The decision whether to admit ‘similar-incident’ evidence is committed to
the sound discretion of the district court,” Arabian Agri. Servs. Co. v. Chief Indus.,
Inc., 309 F.3d 479, 485 (8th Cir. 2002), and we will not overturn the decision to admit
OSI evidence absent a clear and prejudicial abuse of discretion, see First Sec. Bank
v. Union Pac. R.R. Co., 152 F.3d 877, 879 (8th Cir. 1998); Drabik v. Stanley-
Bostitch, Inc., 997 F.2d 496, 508 (8th Cir. 1993).

      OSI evidence “may be relevant to prove the defendant’s notice of defects, the
defendant’s ability to correct known defects, the magnitude of the danger, the
product’s lack of safety for intended uses, or causation.” Lovett ex rel. Lovett v.
Union Pac. R.R. Co., 201 F.3d 1074, 1081 (8th Cir. 2000); see Fed. R. Evid. 401
(evidence must be relevant).3 “Evidence of prior accidents is admissible only if the

      3
        The district court instructed the jury that it could consider the OSI evidence
only to determine whether there was an unreasonably dangerous defect in Lee’s 1996
Camry.

                                          -8-
proponent of the evidence shows that the accidents occurred under circumstances
substantially similar to those at issue in the case at bar.” Hale v. Firestone Tire &
Rubber Co., 756 F.2d 1322, 1332 (8th Cir. 1985). An OSI need not “occur in
precisely the same manner in order to qualify as being substantially similar.” Joy v.
Bell Helicopter Textron, Inc., 999 F.2d 549, 554 (D.C. Cir. 1993).

        The district court permitted three witnesses to testify about purportedly similar
incidents: Michael Frazier, Ronald Neumeister, and Patrick Powers. Michael Frazier
testified that his family purchased a 1996 Camry in 1998. In September 2006, after
his daughter reported a problem with the car, Frazier attempted to drive the Camry
from Boston to Rhode Island—approximately 75 miles. Frazier explained that he
drove the Camry through a tunnel in stop-and-go traffic with little need to use the
accelerator; releasing his foot from the brake pedal was enough to let the car crawl
forward. At one point when Frazier removed his foot from the brake pedal, the
Camry lurched forward. Frazier testified that he tapped the gas pedal and the car
returned to normal. The car lurched again 30 seconds later. Frazier again tapped the
accelerator, keeping his left foot on the brake pedal, but the racing “got worse” each
time, meaning the engine revved “even more.” Frazier put the car in neutral and
turned off the engine in an attempt to gain control of the car, but the engine continued
racing when he reignited it. Frazier had both feet on the brake pedal and used the full
weight of his body to control the car with the brakes. When he was able to exit the
tunnel and get to the side of the road, the Camry had caught fire. A mechanic told
Frazier the cause of the revving was a “sticky valve.” The Camry had approximately
135,000 miles on it at the time of this incident.

       Ronald Neumeister testified that his family purchased a 1996 Camry in 1998
and drove it without incident until 2006. Then, Neumeister described an incident
where he applied pressure to the gas pedal to accelerate up a highway on-ramp until
he reached a speed of approximately 60 miles per hour. When Neumeister released
his foot from the accelerator, the Camry continued accelerating. Neumeister testified


                                          -9-
that he immediately checked to see if something had jammed the gas pedal, but found
nothing unusual. Neumeister put the car in neutral and steered it to the side of the
highway. After inspecting the car, Neumeister turned it back on and drove home.
The Camry had over 100,000 miles on it at the time of this incident. Neumeister also
testified that on several other occasions, the engine would accelerate immediately
upon his starting the Camry, and that he experienced one other incident of unintended
acceleration after applying pressure to the gas pedal while driving.

        Dr. Patrick Powers testified that he purchased a used 1996 Camry in 2000 or
2001. The Camry had approximately 160,000 miles on it when Powers purchased it.
In 2008, Powers accelerated onto the freeway and then took his foot off the gas pedal,
but the Camry continued accelerating. Thinking the gas pedal may be stuck, Powers
tapped it with his foot. However, tapping the gas pedal caused the car to continue to
“accelerate wide open,” “as if the gas was floored.” The brakes did not respond to
normal pressure, and only responded slightly when Powers put both feet on the brake
and applied the full weight of his body, which caused the car to smoke. Powers
testified that his car accelerated to a speed of at least 95 miles per hour, with a
maximum speed of perhaps 120 miles per hour. Powers attempted to put the car in
neutral several times before he was successful. When Powers put the Camry in
neutral the final time, he was able to regain control of the vehicle, coast to the side
of the road, and turn the car off. After exiting the highway, Powers experienced
several instances where the accelerator stuck at a particular speed, but did not
accelerate independently. He testified on redirect examination that the brakes “had
no measurable effect whatsoever” in the first two miles of the highway incident.

      On cross examination, Toyota elicited testimony from both Powers and
Neumeister that the acceleration problem did not reappear after a mechanic cleaned
the throttle body on each of their Camrys. However, the testimony of Frazier,
Powers, and Neumeister established that these men and their mechanics were largely
unable to identify the cause of the unintended acceleration.


                                         -10-
        Toyota argues that the plaintiffs failed to establish that the OSIs were caused
by the same defect alleged in this case, and that the district court therefore abused its
discretion in admitting the OSI evidence for the purpose of proving a defect. Toyota
concedes that our court “has not held that proponents must show that the
other-incidents were caused by the same or similar defect,” but argues that our “cases
foreshadow that conclusion.” Our case law is well-established: Similar incident
evidence is admissible only if the incidents “occurred under circumstances
substantially similar to those at issue in the case at bar.” Hale, 756 F.2d at 1332. But
“[t]here are no hard or fast rules as to what degree of similarity there must be to make
the evidence admissible.” Henwood v. Chaney, 156 F.2d 392, 397 (8th Cir. 1946).
Rather, in determining the admissibility of OSI evidence, the appropriate focus is on
all of the “circumstances” surrounding the OSI evidence, not necessarily any specific
similarity. See Torbit v. Ryder, 416 F.3d 898, 903 (8th Cir. 2005); Hale, 756 F.2d at
1332; see also U.S. Aviation Underwriters, Inc. v. Pilatus Bus. Aircraft, Ltd., 582
F.3d 1131, 1147–48 (10th Cir. 2009).

       We have, for example, found an abuse of discretion in allowing similar incident
evidence when the facts showed that “the circumstances of the accidents differ[ed].”
Hale, 756 F.2d at 1332 (district court improperly allowed evidence of prior accidents
involving “explosive separation of RH5E rims, with no restriction as to the
circumstances or the dates of the accidents”). Conversely, we have found no abuse
of discretion in allowing OSI evidence when the district court concluded that the prior
incidents “occurred under circumstances substantially similar to those” at issue in the
case. Arabian Agric. Servs. Co., 309 F.3d at 485 (no abuse of discretion in allowing
evidence of other collapsing silos; even if the court erred in refusing to give a limiting
instruction regarding the OSI silos, there was no evidence of prejudice where the
defendant was “afforded the opportunity to examine and cross-examine witnesses
extensively regarding the” OSIs); see also Ahlberg v. Chrysler Corp., 481 F.3d 630,
637 (8th Cir. 2007) (district court did not abuse its discretion in excluding evidence
of a prior accident unless it involved “(1) a Jeep or Dodge truck with an automatic


                                          -11-
transmission manufactured [in a similar time frame], (2) with a key left in the
ignition, and (3) a child under age four”); Lewy v. Remington Arms Co., 836 F.2d
1104, 1107–09 (8th Cir. 1988) (OSI evidence involving same-model firearms
admissible, but incidents involving a different model were not admissible). The
inquiry into whether other incident evidence occurred under similar circumstances to
those in the case at hand is case-specific, and no one factor is dispositive.

        Here, the evidence showed that the circumstances surrounding each OSI and
the incident in this case were similar in several respects. Each OSI witness testified
that he drove a 1996 Camry with over 100,000 miles—just like Lee. Each witness
testified that his Camry either accelerated or maintained its speed when he removed
his foot from the gas pedal on at least one occasion—just like Lee. Each witness
testified that the brakes were either ineffective or were very little help in reducing the
Camrys’ speed—just like Lee. Each witness testified that the problem occurred
spontaneously and unpredictably, and that he was unable to regain control of the
Camry within 600 feet of first experiencing the acceleration—just like Lee. The
plaintiffs’ expert, Dr. Stilson, reviewed the OSI evidence prior to trial, and was
present for the testimony of both Neumeister and Frazier. He testified that he
considered Frazier’s and Neumeister’s experiences to be similar to Lee’s. See Torbit,
416 F.3d at 903.

       We also note the careful attention the district court gave the OSI evidence,
addressing Toyota’s argument regarding the exclusion of this testimony on at least
three separate occasions. The court demonstrated a keen awareness of the potential
dangers of admitting such evidence, explaining that it did not want the OSI evidence
to “obscure from the liability case of the plaintiffs,” or “overcome the jury’s focus,”
and that “jury confusion is an issue that [the court] wants to make sure [it] always has
in mind.” The district court was in the best position to determine whether this
evidence would be unduly distracting to the jurors in this case, see Olson v. Ford
Motor Co., 481 F.3d 619, 623 (8th Cir. 2007), and it exercised cautious discretion in


                                          -12-
limiting the number of OSI witnesses to three. We decline to require a series of mini-
trials on the causation of OSI evidence in order for the evidence to be admissible
when, as here, the record demonstrates that the circumstances surrounding these OSIs
were substantially similar to the incident at issue. Instead, in this case, questions as
to the precise cause of the OSIs go toward the weight to be assigned the OSI
evidence, not its admissibility. See Ahlberg, 481 F.3d at 637; Kehm v. Procter &
Gamble Mfg. Co., 724 F.2d 613, 625–26 (8th Cir. 1983). A party is free to “argue to
the jury that the evidence is not persuasive by pointing out dissimilarities” in the OSI
evidence. Lewy, 836 F.2d at 1108; see also Joy, 999 F.2d at 554–55 (finding no
abuse of discretion in admitting OSI evidence, even where “difference in the mode
of failure weighs against” finding substantial similarity, where there are sufficient
shared circumstances and when the evidence was offered to rebut defense theory).

       We remain mindful that admitting similar-incident evidence carries the risk of
raising “extraneous controversial points, lead[ing] to a confusion of the issues, and
present[ing] undue prejudice disproportionate to its usefulness.” First Sec. Bank, 152
F.3d at 879–80 (quoting Drabik, 997 F.2d at 508). In this case, the district court took
those concerns into consideration before admitting evidence of a limited number of
substantially similar incidents. In so doing, the district court did not abuse its
discretion.

B.    Expert Testimony of Stilson

       Toyota also argues that the district court erred in allowing the testimony of the
plaintiffs’ expert, John Stilson. “We review a district court’s decision concerning the
admission of expert testimony for an abuse of discretion.” Miller v. Baker Implement
Co., 439 F.3d 407, 412 (8th Cir. 2006); see Gen. Elec. Co. v. Joiner, 522 U.S. 136,
141–43 (1997).




                                         -13-
       The admissibility of expert testimony is governed by Federal Rule of Evidence
702. “The inquiry envisioned by Rule 702 is . . . a flexible one. Its overarching
subject is the scientific validity—and thus the evidentiary relevance and
reliability—of the principles that underlie a proposed submission.” Daubert v.
Merrell Dow Pharma., Inc., 509 U.S. 579, 594–95 (1993) (footnote omitted). The
party calling an expert must demonstrate the reliability of the expert’s opinion by a
preponderance of the evidence. Id. at 592 n.10. “This entails a preliminary
assessment of whether the reasoning or methodology underlying the testimony is
scientifically valid and of whether that reasoning properly can be applied to the facts
in issue.” Id. at 592–93. “[W]here [an expert’s] factual basis, data, principles,
methods, or their application are called sufficiently into question . . . the trial judge
must determine whether the testimony has ‘a reliable basis in the knowledge and
experience of the relevant discipline.’” Kumho Tire Co., Ltd. v. Carmichael, 526
U.S. 137, 149 (1999) (quoting Daubert, 509 U.S. at 592). In determining whether
expert testimony is admissible, “[t]he focus, of course, must be solely on principles
and methodology, not on the conclusions that they generate.” Daubert, 509 U.S. at
594–95.

       Stilson is a mechanical engineer and an independent automotive safety
consultant with prior experience working as a product design engineer for Chrysler
Corporation and Ford Motor Company. Toyota does not dispute that Stilson is
qualified as an expert by “knowledge, skill, experience, training, or education” in the
area of automotive engineering. Fed. R. Evid. 702. As a qualified expert, Stilson
was permitted to offer an opinion provided it was based on “sufficient facts or data,”
and was the “product of reliable principles and methods.” Id. In assessing the
reliability of an expert opinion, the court may consider, among other things, whether
a given theory or technique has been tested or subjected to peer review and whether
a “technique enjoys ‘general acceptance’ within a ‘relevant scientific community.’”
Kumho Tire Co., 526 U.S. at 149–50 (quoting Daubert, 509 U.S. at 592–94). Toyota
argues that the district court abused its discretion in admitting Stilson’s opinions


                                          -14-
under Rule 702 because his testing does not support his theory of defect and because
he relied on insufficient evidence in concluding that the alleged defect caused the
accident. We disagree.

       First, Toyota argues that Stilson’s opinions should have been excluded because
his testing methodology was faulty and did not analytically support his hypothesis.
Stilson testified that he followed protocol and utilized methodology that Toyota itself
recommended for testing the heat capacity of the component parts of its 1996 Camry.
Cf. Presley v. Lakewood Eng’g & Mfg. Co., 553 F.3d 638, 645–46 (8th Cir. 2009)
(expert opinion inadmissible when proposed expert conducted no tests and did not
reliably apply relevant standards in the field). Though the parties dispute the
significance of Stilson’s repositioning the cruise control arm during his thermal
testing, Stilson thoroughly explained how he modified the cruise control system and
why he did so. He testified that, in his opinion as an engineer, the modification did
not affect the validity of the thermal testing because the cruise control system
operated independently of the throttle mechanism that was the subject of his testing.
He explained that his testing supported the conclusion that the throttle pulleys fused
together when subjected to high temperatures. See Shuck v. CNH Am., LLC, 498
F.3d 868, 875 n.3 (8th Cir. 2007) (concluding that “testing, if performed, must be
appropriate in the circumstances and must actually prove what the experts claim it
proves” (discussing Fireman’s Fund Ins. Co. v. Canon U.S.A., Inc., 394 F.3d 1054
(8th Cir. 2005))). To the extent that repositioning the cruise control lever affected
Stilson’s testing, he was subject to cross-examination about the significance of this
modification. See Daubert, 509 U.S. at 596 (“Vigorous cross-examination,
presentation of contrary evidence, and careful instruction on the burden of proof are
traditional and appropriate means of attacking shaky but admissible evidence.”)

       Toyota also takes issue with Stilson’s conclusion that the cause of Lee’s
accident was the thermal-induced sticking defect in the accelerator control system.
Stilson explained that his testing revealed a stuck throttle at a temperature of between


                                         -15-
160 and 165 degrees Fahrenheit.4 Stilson testified that the plastic dust cover encasing
the throttle acted like a “sauna,” trapping heat generated from both inside and outside
the dust cover. He opined that the dust cover had “gaps” through which heat could
enter, but, because the cover was closed on the top, the heat could not easily escape.
Stilson also noted that the accelerator control system, housed in the dust cover, was
approximately seven inches away from the exhaust manifold—a part of the engine
that reached 900 or 1000 degrees Fahrenheit—and that some of this heat would
transfer into the dust cover. Finally, Stilson testified that he was able to rule out
pedal misapplication as the cause of the accident, based in part on Lee’s account of
the incident and in part on mechanical evidence retrieved from Lee’s Camry.

       “[T]he district court must . . . function as a gatekeeper who ‘separates expert
opinion evidence based on good grounds from subjective speculation that
masquerades as scientific knowledge.’” Presley, 553 F.3d at 643 (quoting Glastetter
v. Novartis Pharm. Corp., 252 F.3d 986, 989 (8th Cir. 2001)). However, Stilson’s
opinion as to causation need not be a “scientific absolute in order to be admissible.”
Bonner v. ISP Tech., Inc., 259 F.3d 924, 929 (8th Cir. 2001). We conclude that
Stilson’s opinions represented more than “vague theorizing based on general
principles,” Pro Serv. Auto., LLC v. Lenan Corp., 469 F.3d 1210, 1216 (8th Cir.
2006), or “unsupported speculation,” Daubert, 509 U.S. at 590. The district court did
not abuse its broad discretion in allowing Stilson’s expert opinion pursuant to Rule
702.

C.    Motion for JAML

     Next, Toyota argues that the district court erred in denying its motion for
judgment as a matter of law. We review a district court’s denial of a motion for

      4
      Stilson’s notes indicated that one of his tests revealed sticking at a temperature
of 150 degrees Fahrenheit, but he testified at trial that sticking was observed at
temperatures of 160 or 165 degrees Fahrenheit.

                                         -16-
JAML de novo. Weisgram v. Marley Co., 169 F.3d 514, 516 (8th Cir. 1999). In so
doing, we “draw all reasonable inferences in favor of [the plaintiffs] without making
credibility assessments or weighing the evidence.” Arabian Agric. Servs. Co., 309
F.3d at 482 (quoting Phillips v. Collings, 256 F.3d 843, 847 (8th Cir. 2001)). We will
“uphold a jury verdict unless we conclude that a reasonable jury could not have found
for that party.” Knutson v. Ag. Processing, Inc., 394 F.3d 1047, 1050 (8th Cir. 2005).

       “State law governs the substance of . . . diversity-based products liability
actions.” Pritchett v. Cottrell, Inc., 512 F.3d 1057, 1063 (8th Cir. 2008). To make
out a cause of action for products liability based on a design defect under Minnesota
law, the plaintiffs were required to prove: (1) the Camry was in a defective condition
that rendered it unreasonably dangerous for its intended use; (2) the defective
condition existed when the Camry left Toyota’s control; and (3) the defect was the
proximate cause of the plaintiffs’ injuries. See Bilotta v. Kelley Co. Inc., 346 N.W.2d
616, 623 n.3 (Minn. 1984). “Proximate cause exists if the defendant’s conduct,
without intervening or superseding events, was a substantial factor in creating the
harm.” Thompson v. Hirano Tecseed Co., Ltd., 456 F.3d 805, 812 (8th Cir. 2006)
(discussing Minnesota law); see Wright v. Willamette Indus., Inc., 91 F.3d 1105,
1106 (8th Cir. 1996).5 Toyota argues that, even assuming Stilson’s opinions and the
OSI evidence were properly admitted, the plaintiffs failed to prove that a defect
existed or that the alleged defect was the proximate cause of the accident. We
disagree.

      The plaintiffs presented sufficient evidence from which a jury could find that
the 1996 Camry contained a design defect. A significant portion of this evidence is


      5
       The district court instructed the jury that, in order to recover on the basis of
a design defect, the plaintiffs had to prove that the “defective condition in the car was
a direct cause of Plaintiffs’ injuries.” The court instructed the jury that a “‘direct
cause’ is a cause that had a substantial part in bringing about the accident.” Neither
party challenges the district court’s instruction.

                                          -17-
discussed in detail above. For example, the plaintiffs presented Stilson’s expert
testimony, supported by tests he conducted pursuant to Toyota’s recommended
protocol for thermal testing. Cf. Fireman’s Fund, 394 F.3d at 1058–59 (insufficient
evidence of defect and causation when expert failed to propose a specific defect or
conduct testing in accordance with industry standards); Weisgram, 169 F.3d at 521
(expert not qualified to testify to conclusions as to product failure given inexperience
with the relevant products). Stilson told the jury that he concluded that the
susceptibility of the throttle pulleys to heat-induced sticking constituted a defect and
explained in great detail the bases for his conclusion. Additionally, the plaintiffs
offered Lee’s testimony and that of his wife, explaining that Lee attempted to apply
the brakes to no avail and that the car continued accelerating on its own; evidence that
Toyota had failed to conduct standard heat-related safety testing on the 1996 Camry’s
throttle mechanism; and OSI evidence.

       The plaintiffs also presented evidence from which a reasonable jury could find
that the throttle defect was “a substantial factor in creating the harm.” Thompson,
456 F.3d at 812. Stilson described the components housed beneath the dust cover
that generated heat, and explained that other parts would transmit heat to the throttle
pulleys. He also noted that heat from components outside the throttle— namely the
exhaust manifold and ambient heat—likely entered and got trapped under the dust
cover, subjecting the pulleys to additional heat. Stilson explained that there was a
“high probability” that heat would remain trapped under the dust cover for a period
of time because there was little opportunity for ventilation. He opined that the
pulleys overheated, stuck together, and ultimately caused the accident at issue in this
case.

       Toyota sought to refute the plaintiffs’ theories of defect and causation through
the testimony of its expert, Steven MacLean. MacLean did not dispute the fact that
the relevant throttle pulleys would expand and stick if subjected to a temperature of
165 degrees Fahrenheit, or that the dust cover containing the pulleys was only seven


                                         -18-
inches away from the 900 degree exhaust manifold. Instead, he asserted that Lee’s
vehicle never reached the temperature necessary to cause sticking. MacLean testified
that he drove a 1995 Camry in a route simulating Lee’s. During this simulation, the
temperature in the test Camry never reached 165 degrees and the throttle pulleys did
not bind together. MacLean opined that the accident was, therefore, not caused by
the alleged defect. Toyota argued alternative theories of causation, including that the
accident was caused by a dirty throttle body or by pedal misapplication—both of
which the plaintiffs attempted to discredit. Toyota argues that MacLean’s testimony,
combined with the fact that the one test Stilson performed with the cruise control
lever in the unmodified position did not result in a stuck throttle, mandates the
conclusion that a reasonable jury could not have found that Lee’s Camry ever got hot
enough for the throttle pulleys to stick. As a result, according to Toyota, the plaintiffs
failed to establish that the alleged defect caused the accident at issue here.

       The jury heard testimony from two qualified experts with competing opinions
regarding the cause of the accident. Both of them testified extensively about their
respective theories of defect and causation and both were subjected to lengthy and
detailed cross-examination. See Johnson v. Mead Johnson & Co., LLC, 754 F.3d
557, 562 (8th Cir. 2014) (“As long as the expert’s scientific testimony rests upon
‘good grounds, based on what is known’ it should be tested by the adversary process
with competing expert testimony and cross-examination, rather than excluded by the
court at the outset.” (quoting Daubert, 509 U.S. at 596)). Though Toyota disagrees
with Stilson’s opinions and conclusions—including his explanation that moving the
cruise control lever did not affect the validity of his testing—“questions of conflicting
evidence must be left for the jury’s determination,” Bonner, 259 F.3d at 930 (quoting
Hose v. Chi. Nw. Transp. Co., 70 F.3d 968, 974 (8th Cir. 1995)), and we will not re-
weigh the evidence, Arabian Agric. Servs., Co., 309 F.3d at 482 (citation omitted).
The jury’s verdict was not based on “sheer speculation,” and instead is supported by
reasonable inferences drawn from the plaintiffs’ evidence. Rients v. Int’l Harvester
Co., 346 N.W.2d 359, 362 (Minn. Ct. App. 1984). Viewing the evidence in the light


                                          -19-
most favorable to the verdict and drawing all reasonable inferences in favor of that
verdict, we conclude that this evidence was sufficient to allow a reasonable jury to
find that the Camry’s design defect was the proximate cause of this accident. See
Bednar v. Bassett Furniture Mfg. Co., Inc., 147 F.3d 737, 739–40 (8th Cir. 1998)
(finding sufficient evidence to withstand summary judgment on causation when
plaintiff offered evidence of what level of toxin is generally harmful and expert
testimony that the plaintiff was exposed to harmful level); cf. Rients, 346 N.W.2d at
362 (insufficient evidence of causation in product liability case when uncontroverted
evidence established numerous other potential causes).

D.    Award of Prejudgment Interest

       Finally, Toyota argues that the district court erred in awarding prejudgment
interest pursuant to Minn. Stat. Ann. § 549.09 on plaintiff Bridgette Trice’s damages
award. “[W]hether the district court had authority to grant prejudgment interest is a
question of state law which we review de novo.” Children’s Broad. Corp. v. Walt
Disney Co., 357 F.3d 860, 868–69 (8th Cir. 2004) (quoting Trans. Cas. Co. v.
Selective Ins. Co. of the S.E., 137 F.3d 540, 546 (8th Cir. 1998)).

      Section 549.09 reads, in relevant part:

      Subdivision 1. When owed; rate. (a) When a judgment or award is for
      the recovery of money, . . . interest from the time of the verdict, award, or
      report until judgment is finally entered shall be computed by the court
      administrator or arbitrator as provided in paragraph (c) and added to the
      judgment or award.

      (b) Except as otherwise provided by contract or allowed by law, preverdict,
      preaward, or prereport interest on pecuniary damages shall be computed
      as provided in paragraph (c) . . . except as provided herein . . . . Except as
      otherwise provided by contract or allowed by law, preverdict, preaward,
      or prereport interest shall not be awarded on the following:


                                       -20-
             (2) judgments or awards for future damages;

      (c)(2) For a judgment or award over $50,000, . . . the interest rate shall be
      ten percent per year until paid.

Minn. Stat. Ann. § 549.09.

       As an initial matter, Trice argues that the jury awarded no future damages
because they were not instructed on, and Trice did not request, future damages. The
record belies this argument. Though the parties agreed that certain instructions on
future damages were unnecessary, the jury was nevertheless instructed that damages,
including those for Devyn Bolton’s next of kin, “may include past and future injury.”
The jury was instructed to determine “what Devyn Bolton would have provided to the
claimants if she had lived” by considering “her life expectancy at the time of her
death,” “her likely future earning capacity and prospects of bettering herself had she
lived,” and, inter alia, “[t]he advice, comfort, assistance, companionship, and
protection” she “would have given if she had lived.” The special verdict form asked
the jury to award damages to Devyn Bolton’s next of kin to compensate for “loss of
counsel, guidance, aid, advice, comfort, assistance, companionship, and protection
Devyn Bolton would have given to her next of kin . . . had she lived.” The jury was
therefore instructed to consider future damages.

       Furthermore, neither party disputes the district court’s finding that it is
impossible to determine which portion of Trice’s award represents pecuniary damages
subject to § 549.09 subdivision 1(c)(2)’s ten percent interest rate and which portion
of the award represents future damages exempt from prejudgment interest under
subdivision 1(b)(2). Because the Minnesota Supreme Court has not articulated how
§ 549.09 applies in such circumstances, we must try to predict “how the state’s
highest court would rule if faced with the same question.” Marvin Lumber & Cedar
Co. v. PPG Indus., 401 F.3d 901, 917–18 (8th Cir. 2005). In making this prediction,
“we may consider relevant state precedent, analogous decisions, considered dicta,

                                         -21-
scholarly works and any other reliable data.” Ventura v. Titan Sports, Inc., 65 F.3d
725, 729–30 (8th Cir. 1995).

        “Prejudgment interest is an element of damages awarded to provide full
compensation by converting time-of-demand damages into time-of-verdict damages.
It is designed to compensate the plaintiff for the loss of the use of the money owed.”
Simeone v. First Bank Nat’l Ass’n, 73 F.3d 184, 190–91 (8th Cir. 1996); see also
Lienhard v. State, 431 N.W.2d 861, 865 (Minn. 1988). Prejudgment interest is also
intended to encourage settlement. See Burniece v. Ill. Farmers Ins. Co., 398 N.W.2d
542, 544 (Minn. 1987) (“Prejudgment interest essentially serves a dual purpose: (1)
to compensate the plaintiff for the loss of use of his money . . . and (2) to promote
settlement.”). In interpreting § 549.09, we aim to “give the statute a meaning which
will carry out its dual purpose.” Johnson v. Kromhout, 444 N.W.2d 569, 571 (Minn.
Ct. App. 1989).

       Section 549.09, subdivision 1(a), explains that prejudgment interest on
pecuniary damages “shall be computed . . . as provided in paragraph (c) and added to
the judgment or award” except as otherwise provided by law. Subdivision 1(b)
explains which damages awards are exempt from the mandate of subdivision 1(a),
specifically noting that interest “shall not be awarded” on future damages. Minn.
Stat. Ann. § 549.09, subd. 1(b)(2); see Baufield v. Safelite Glass Corp., 831 F. Supp.
713, 719 (D. Minn. 1993) (“[T]he threshold issue is whether an award of prejudgment
interest is proper. Minn. Stat. § 549.09, subd. 1(b)(1)–(5) sets forth specific
judgments for which preverdict interest may not be awarded.”). There is no inherent
conflict between § 549.09 subdivision 1(a) and § 549.09 subdivision 1(b)(2).
However, in this case, where we have a lump sum including some damages whose
interest “shall be computed” in accordance with the statute and some damages that
“shall not” be subject to interest, we cannot simultaneously give effect to both
provisions. “[U]nder well-settled rules of statutory construction, the specific
limitation on preaward interest in Minn. Stat. § 540.09, subd. 1(b)(4)” therefore


                                        -22-
prevails over the more general interest provision articulated in § 549.09, subdivision
1(a), and Trice was not entitled to prejudgment interest. Garlyn, Inc. v. Auto-Owners
Ins. Co., 814 N.W.2d 709, 715 (Minn. Ct. App. 2012) (citing Minn. Stat. Ann. §
645.26, subd. 1 (2010) and Matter of Ret. Benefits of Yetka, 554 N.W.2d 85, 91
(Minn. Ct. App. 1996)).

       Several lower court cases support this interpretation. In Stinson v. Clark
Equipment Co., 473 N.W.2d 333 (Minn. Ct. App. 1991), the Minnesota Court of
Appeals addressed whether the district court erred in awarding prejudgment interest
on a settlement agreement. The agreement provided for a lump sum plus costs and
disbursements. Id. at 334. In determining prejudgment interest, the court noted that
“the parties agreed to damages for personal injury in the amount of $240,000 without
differentiating between types of damages.” Id. at 336. It explained that it therefore
did “not know if there are pecuniary damages, nor . . . the amount of future damages
on which the statute explicitly disallows prejudgment interest.” Id. The court
concluded that, “[b]ecause the types of damages are unascertainable, the amount of
prejudgment interest is indeterminable,” and found § 549.09 was “inapplicable.” Id.;
see also Hagen v. State Bank of Cokato, No. C9-88-1407, 1989 WL 12432, at *2
(Minn. Ct. App. Feb. 21, 1989) (unpublished) (“As the jury verdict did not distinguish
between past and future damages and the statute plainly says interest cannot be
awarded for future damages, the trial court did not err in denying prejudgment
interest.”).

      Similarly, Minnesota courts have consistently remanded to the trial court where
the lower court failed to make a finding as to what portion of a lump sum award is
subject to prejudgment interest. See Muehlhauser v. Erickson, 621 N.W.2d 24, 30–31
(Minn. Ct. App. 2000) (remanding where the parties agreed that district court erred
in awarding interest on future damages); Johnson v. Washington Cty., 506 N.W.2d
632, 640 (Minn. Ct. App. 1993) (remanding for recalculation of interest where district
court awarded interest on entire sum and did not “determine what portion of the


                                        -23-
verdict constituted future damages”); Wirig v. Kinney Shoe Corp., 448 N.W.2d 526,
535 (Minn. Ct. App. 1989), aff’d in part, 461 N.W.2d 374 (Minn. 1990) (remanding
for recalculation of interest award where trial court ordered preverdict interest on
compensatory, future, and punitive damages). In this case, the district court did not
fail to consider which portion of the award constituted future damages; instead, it
specifically found that such a determination was impossible. As noted, neither party
challenges this finding, so remanding under these circumstances would be futile.

       Taking into account the plain language of § 549.09, lower state court decisions,
and the purpose of the statute, see Leinhard, 431 N.W.2d at 865 (prejudgment interest
is an element of damages), we predict that the Minnesota Supreme Court would
conclude that prejudgment interest is not available for judgments that encompass
multiple types of damages—some of which are subject to interest under § 549.09 and
some of which are not—when it is impossible to differentiate between the types of
damages included in the judgment. We therefore conclude that the district court erred
in awarding prejudgment interest on the damages awarded to Trice by the jury and
vacate the award of prejudgment interest on this amount.6

E.    Reduction of plaintiff Bridgette Trice’s Award

      On cross-appeal, Trice argues that the district court erred in offsetting her
award to account for a prior settlement she entered into with Lee and Lee’s insurance
provider. Whether a pro tanto settlement offset applies is a question of state law
subject to de novo review. See Neb. Plastics, Inc. v. Holland Colors Ams., Inc., 408
F.3d 410, 419 (8th Cir. 2005).




      6
       This ruling does not affect the stipulated past damages, which the parties
agreed to prior to or during the trial and were added to the jury’s award following the
verdict.

                                         -24-
      Prior to the filing of this cause of action, while Devyn was still living, Trice
signed a release agreement on behalf of Devyn as Devyn’s mother and natural
guardian. The agreement released Lee and his insurers,

      their officers, employees, representatives, successors, assigns and all other
      persons, firms and corporations from any and all liability, actions, causes
      of action, claims and demands . . . for any damages, for losses or injuries
      which heretofore have been or which hereafter may be sustained by me in
      consequence of the incident which occurred on or about June 10, 2006.

However, the release explained that it is “not to be construed as a waiver by or as an
estoppel of any parties hereby released to prosecute a claim or cause of action against
any other person, firm, or corporation for damages sustained as a result of the said
accident hereinabove referred to . . . .” When parties execute a release agreement that
does not result in the plaintiff being fully compensated for the harm she
suffered—like the one in this case—the release generally “operates as a satisfaction
pro tanto as to other tortfeasors.” Johnson v. Brown, 401 N.W.2d 85, 88 (Minn. Ct.
App. 1987); see also Gronquist v. Olson, 64 N.W.2d 159, 165 (Minn. 1954). Here,
the district court found that Trice’s release agreement with Lee and his insurers fell
within this general rule, and applied a pro tanto offset to Trice’s award in the amount
Trice received from Lee and Lee’s insurers.

       Pro tanto satisfaction is based on the principle that “an injured person can have
but one full satisfaction for his injuries,” and cannot recover twice for the same
injury. Id. However, in the instant case, there is no danger of a duplicative award
because the release agreement and the jury verdict benefitted different plaintiffs.
There is a “clear distinction” between a guardian representing the personal interests
of a minor child and a wrongful death trustee as the personal representative of a
decedent’s next of kin. Steinlage ex rel. Smith v. Mayo Clinic Rochester, 435 F.3d
913, 916 (8th Cir. 2006). In executing the release agreement, Trice acted as Devyn’s
“mother and natural guardian.” As such, she executed the agreement and received


                                         -25-
benefits on behalf of Devyn. In contrast, as the wrongful death trustee, Trice acted
and received benefits on behalf of Devyn’s next of kin, and was prohibited from
recovering damages on Devyn’s behalf.7 See Minn. Stat. Ann. § 573.02, subd. 1
(damages awarded under § 573.02 for wrongful death “shall be for the exclusive
benefit of the . . . next of kin” in “the amount the jury deems fair and just in reference
to the pecuniary loss resulting from the death.”); Steinlage, 435 F.3d at 916–17
(“[U]nder current Minnesota law, only a court-appointed wrongful death trustee may
maintain a wrongful death action, and the wrongful death trustee does not represent
the estate of the decedent.”); Johnson v. Consol. Freightways, Inc., 420 N.W. 2d 608,
613 (Minn. 1988) (Section 573.02 “does not allow survival of a decedent’s action, but
rather creates an entirely new cause of action, the beneficiaries of which are third
parties claiming pecuniary loss from the wrongdoer’s act”); Shumway v. Nelson, 107
N.W.2d 531, 533 (Minn. 1961) (explaining that an action under § 573.02 “creates an
entirely new cause of action for the purpose of compensating the next of kin who
have suffered pecuniary loss by reason of the death of the decedent. It is not brought
for the benefit of the decedent”).

       The purpose of § 573.02, subdivision 1 is to fully compensate a decedent’s next
of kin for their pecuniary losses. See Gronquist, 64 N.W.2d at 164 (“[I]f [the injured
party] has not received full satisfaction, or that which the law considers such, he is
not barred until he has received full satisfaction.”). Allowing Devyn Bolton’s next
of kin to recover the full amount of the jury award in this case is not inequitable




      7
        The court’s instructions reflected this distinction. The court instructed the jury
that it could compensate Devyn’s next of kin for “damages arising from Devyn
Bolton’s death,” by awarding an amount that would “fairly and adequately
compensate [the next of kin] for the losses they suffered as a result of this death,” but
instructed the jury not to consider amounts for “the pain and suffering of Devyn
Bolton before her death.”

                                          -26-
because Devyn recovered for her own injuries while she was living.8 See Steinlage,
435 F.3d at 916 (8th Cir. 2006). We therefore conclude that Trice’s award should not
be reduced by the amount that Devyn previously recovered from Lee and Lee’s
insurers.

                                   III. Conclusion

       For the reasons articulated above, we affirm in part, reverse in part, and remand
for further proceedings consistent with this opinion.
                        ______________________________




      8
        The cases cited by Toyota examining other state wrongful death laws do not
establish otherwise. See Thompson v. R.J. Reynolds Tobacco Co., 760 F.3d 913, 916
(8th Cir. 2014) (addressing Missouri law); Huff v. Fibreboard Corp., 836 F.2d 473,
476 (10th Cir. 1987) (interpreting Oklahoma statute to bar a wrongful death action
when decedent would not have had a cause of action at the time of his death because
the applicable statute of limitations had expired); Smith v. Brown & Williamson
Tobacco Corp., 275 S.W.3d 748, 761–80 (Mo. Ct. App. 2008) (finding that a
wrongful death action under Missouri statute was not barred by the decedent’s
“personal injury action during her lifetime for injuries resulting from the same cause
of her death”).

                                         -27-
