PUBLISH 

UNITED STATES COURT OF APPEALS 

FOR THE TENTH CIRCUIT 

_________________________________ 

NATHAN PETERSEN, 

 Plaintiff - Appellant, 

v. 

THE RAYMOND CORPORATION, 

 Defendant - Appellee. 

No. 20-4026 

_________________________________ 

Appeal from the United States District Court 

for the District of Utah 

(D.C. No. 2:14-CV-00894-RJS)

_________________________________ 

Michael J. Warshauer of Warshauer Law Group, P.C., Atlanta, Georgia (David A. Cutt of 

Eisenberg Cutt Kendell & Olson, Salt Lake City, Utah, with him on the briefs), for 

Plaintiff-Appellant. 

Francis H. LoCoco of Husch Blackwell LLP, Milwaukee, Wisconsin (Rick L. Rose and 

Kristine M. Larsen, of Ray Quinney & Nebeker, Salt Lake City, Utah, with him on the 

brief), for Defendant-Appellee. 

_________________________________ 

Before TYMKOVICH, Chief Judge, BALDOCK, and CARSON, Circuit Judges. 

_________________________________ 

CARSON, Circuit Judge. 

_________________________________ 

The district court serves as a gatekeeper, shutting the door on unreliable expert 

testimony. See Kumho Tire Co., Ltd. v. Carmichael, 526 U.S. 137, 152 (1999). And 

we afford district courts “considerable leeway” in deciding when the door should be 

FILED 

United States Court of Appeals 

Tenth Circuit 

April 22, 2021

Christopher M. Wolpert 

Clerk of Court
2 

closed. Id. Plaintiff Nathan Petersen (“Plaintiff”) argues the district court 

impermissibly closed the door on the strict products liability claim he brought against 

Defendant Raymond Corporation (“Raymond”) alleging it defectively manufactured 

a forklift. In support of his claim he sought to offer expert testimony that the forklift 

would be safer if it had “a door” on it. The district court found the expert’s 

testimony unreliable and excluded it. It then granted a related motion for summary 

judgment in Raymond’s favor. Plaintiff appeals. Exercising jurisdiction under 28 

U.S.C. § 1291, we affirm. 

I. 

Plaintiff injured himself while operating the Raymond Model 4200 stand-up 

counterbalance lift truck (“Raymond forklift”). The Raymond forklift has an open 

compartment. So it does not fully enclose the operator’s lower extremities. When 

Plaintiff lost control of the Raymond forklift, his left leg slid out of the open 

compartment and he crushed it against warehouse racking. 

Plaintiff sued the Raymond forklift manufacturer—Raymond—alleging strict 

liability. Plaintiff asserted the Raymond forklift’s open compartment made it 

defective. And he tried to offer expert testimony from Plaintiff’s expert in support of 

that assertion. Plaintiff’s expert concluded that adding a door could cure this 

deficiency. But Plaintiff’s expert did not commit to the specific type of door he 

believed necessary. Instead, he offered that any number of doors would have 

worked. 
3 

Raymond moved to exclude Plaintiff’s expert’s testimony. It then moved for 

summary judgment, arguing that Plaintiff could not meet his burden without expert 

testimony. Before ruling on these motions, the district court reviewed Plaintiff’s 

expert’s 76-page report and ordered supplemental cross briefing on the admissibility 

of his opinions. It also held three evidentiary hearings where Plaintiff’s expert 

testified about his opinions. 

After review, the district court issued an extensive oral ruling excluding 

Plaintiff’s expert’s testimony that, in general, a door presented a safer, alternative 

design option. It reasoned that although Plaintiff’s expert was qualified to offer this 

opinion, he failed to offer a specific safer, alternative design and thus failed to 

reliably support his opinion. Because Plaintiff lacked expert testimony that a safer, 

alternative design existed at the time of his injuries, he could not meet his burden for 

a Utah strict liability claim. So the district court granted summary judgment in 

Raymond’s favor. Plaintiff appeals. 

II. 

The district court delivered its decision excluding Plaintiff’s expert in an oral 

ruling that lasted nearly two hours. The ruling lacked some precision, making 

appellate review more difficult, but we see no need to remand for clarification. 

We review a district court’s decision to exclude testimony for abuse of 

discretion. See Bitler v. A.O. Smith Corp., 400 F.3d 1227, 1232 (10th Cir. 2005). So 

we will not “disturb a district court’s ruling absent our conviction that it is arbitrary, 
4 

capricious, whimsical, manifestly unreasonable, or clearly erroneous.” Id. (citing 

Goebel v. Denver and Rio Grande W. R.R. Co., 346 F.3d 987, 990 (10th Cir. 2003)). 

We review de novo a district court’s grant of summary judgment. Allen v. 

Minnstar, Inc., 8 F.3d 1470, 1476 (10th Cir. 1993). The district court must grant 

summary judgment only if the “moving party is entitled to judgment as a matter of 

law.” Fed. R. Civ. P. 56(c). Because this case arises out of diversity, we apply Utah 

law. Allen, 8 F.3d at 1476. 

III. 

A. 

In determining whether an expert may testify under Federal Rule of Evidence 

702, the district court must first consider whether the expert’s proffered testimony 

has “a reliable basis in the knowledge and experience of his discipline.” Daubert v. 

Merrell Dow Pharms., Inc., 509 U.S. 579, 592 (1993). When making this 

determination, the district court should examine “whether the reasoning or 

methodology underlying the testimony is scientifically valid . . . .” Id. at 592–93. 

The district court excluded Plaintiff’s expert’s opinions for two reasons. First, 

Plaintiff’s expert failed to definitively offer a specific safer, alternative design. 

Second, he failed to reliably support his opinion that any door would be a safer, 

alternative design. We will address each reason in turn. We conclude the district 

court did not abuse its discretion in excluding Plaintiff’s expert’s opinions, and 

therefore affirm its grant of summary judgment in Raymond’s favor. 
5 

Under Utah law, a plaintiff bringing a strict products liability claim must show 

that at the time of the injury an “alternative, safer design, practicable under the 

circumstances” existed. Allen, 8 F.3d at 1479. Plaintiff argues the district court 

unlawfully found that Utah law limits a plaintiff to offering only one alternative 

design. But the district court did not make such a finding. In fact the district court 

explicitly referenced that sometimes “multiple design options are warranted.” ROA 

at 1932. 

The district court found that Plaintiff’s expert failed to commit to any 

definitive feasible design alternative.1

 And it rightfully excluded his testimony on 

that basis. The Fifth Circuit upheld a district court’s exclusion of expert testimony 

for the same reason in Guy v. Crown Equip. Corp. 394 F.3d 320, 323 (5th Cir. 

2004).2 In Guy, a plaintiff operating a forklift with an open compartment lost 

control, and her left leg came out of the compartment and she crushed it. Id. The 

1

 The district court made multiple comments to this effect when issuing the 

oral ruling. ROA at 1917, 1918, 1919–1920, 1921 & 1925–1926. But on whole the 

message remained the same, the district court believed Plaintiff’s counsel took “the 

unworkable and unfair position that they need not select a specific safer alternative 

design to enable Raymond, the jury, and this court to compare the open back design 

they criticize with the proposed alternative.” ROA at 1894 (emphasis added). 

2

 In Guy, the plaintiff brought strict liability claims under the Mississippi 

Products Liability Act (“MPLA”). 394 F.3d at 322–23. The MPLA requires the 

plaintiff to show the existence of “a feasible design alternative that would have to a 

reasonable probability prevented the harm.” MISS. CODE ANN. § 11-1-63(f)(ii). 

Although the MPLA defines “feasible design alternative” and Utah does not, the 

MPLA’s requirement is sufficiently analogous to Utah’s strict liability requirement 

that a plaintiff show a safer, alternative design existed at the time of the plaintiff’s 

injury. 
6 

plaintiff brought a strict liability claim against the forklift manufacturer. Id. In 

support of her claim she sought to have an expert testify that the forklift was 

defective, in part, because it lacked “an operator restraint (similar to a seat belt)[.]” 

Id. As a design alternative, the expert advocated use of a “restraining device” but 

“never presented a specific design.” Id. at 327. The district court excluded the 

expert’s testimony because the expert “had not presented any definitive theory, 

opinion or . . . feasible design alternative . . . that could be tested . . . .” Id. at 323. 

The Fifth Circuit held the district court acted within its discretion in excluding the 

expert’s testimony because although the expert suggested devices like those already 

on the market would suffice, “he never submitted a complete ‘end product.’” Id. 

at 327. “‘The proper methodology for proposing alternative designs includes more 

than just conceptualizing possibilities[,]’” so the expert’s failure to offer a specific 

alternative rendered his testimony inadmissible. Id. (quoting Watkins v. Telsmith, 

Inc., 121 F.3d 984, 992 (5th Cir. 1997)). 

Like the Guy plaintiff, Plaintiff here operated a forklift with an open 

compartment. He lost control, his left leg came out of the compartment and he 

crushed it. Plaintiff’s expert, like the Guy expert, never presented a definitive safer, 

alternative design. In fact, he made a point not to commit to any specific design. He 

only advocated the use of “a door” and offered conceptualized possibilities.3

 The 

3

 In his expert report, Berry offered as his alternative design that— 

The lift truck could have been provided with several designs of doors 

including, but not limited to, a latching rear door, a spring loaded door, 
7 

district court here, like the district court in Guy, excluded expert testimony for failure 

to present any testable definitive design. The district court did not limit Plaintiff’s 

expert to submitting only one design. But it did require that Plaintiff’s expert offer at 

least one definitive safer, alternative design. Without a definitive design, neither 

Plaintiff’s expert nor the district court could meaningfully compare any proffered 

design with the existing design. And neither could a jury. For this reason, the 

a magnet controlled door, and an interlocked door to provide further 

protection to operators from additional hazards. Properly designed doors 

that exist in the marketplace right now, or which could be easily 

manufactured (see the Elrod door) would have a negligible effect on the 

maintenance of the machine. The door should have been constructed out 

of a suitable material that would withstand the forces of impact 

generated during collisions, intrusions, tipovers and off-the-dock 

accidents. (Intrusion protection is not the primary purpose of the door 

needed to protect Mr. Peterson so while intrusion protection is helpful, 

it is not essential to improve the safety of the machine so long as the 

door will assist the operator in keeping his leg inside the operator’s 

compartment.) The cost of providing such a rear door would be 

insignificant relative to the cost of the forklift. The cost of adding a 

latching rear guard to the Raymond 420-C50QM would have cost at 

most $250 if designed and installed at the time of manufacture rather 

than as an add-on. 

Berry did not commit to any type of door, material of door, cost of door. He 

also does not specify how a manufacturer would add “a door” to the Raymond 

forklift despite admitting that to put a door on a forklift you would need to know 

where the hinges went. He did admit, however, that “rugged hinges [were] available 

for use.” But again, he never stated that he would use rugged hinges here. He only 

offers that rugged hinges exist. He did not specify the measurements for “a door” 

despite admitting that one would have to know whether the door spanned the 

entrance. He did not discuss how a manufacturer may hook the door up to the 

forklift’s electrical and computer systems despite admitting that someone would need 

to know whether such a hookup was possible. He also said he had not designed a 

specific door for the Raymond forklift. Defendant’s counsel asked Berry in a 

hearing, “[d]o you have any engineering drawings to show us of your design of a 

door for [the Raymond forklift]?” Berry responded, “[n]o.” 
8 

district court did not abuse its discretion in excluding Plaintiff’s expert’s testimony 

for failure to offer any specific safer, alternative design. 

B. 

Plaintiff argues the district court’s misunderstanding of Utah law—on how 

many alternative designs a plaintiff can advance—permeated its ruling that Plaintiff’s 

expert did not offer a scientifically reliable expert opinion. Not true. Again, the true 

issue is not numerosity, it is design specificity. Because Plaintiff’s expert offered no 

specific design, he did not test any specific design on the Raymond forklift, nor did 

he cite testing done by others of a specific design on the Raymond forklift. 

Plaintiff makes two assertions, neither of which advances the ball. First, 

Plaintiff asserts Plaintiff’s expert did not have to test “a door” on the Raymond 

forklift himself. Although Rule 702 did not require Plaintiff’s expert to do the 

testing himself, we have upheld the exclusion of an expert’s testimony for lack of 

sufficient methodology and reasoning where the expert relied on published material 

rather than testing his theory directly. See United States v. Gabaldon, 389 F.3d 1090, 

1099 (10th Cir. 2004). And other circuits have excluded expert testimony on that 

same basis in forklift cases specifically. See Brown v. Raymond Corp., 432 F.3d 

640, 647–48 (6th Cir. 2005) (concluding that an expert witness’s failure to provide 

evidence of testing on his own alternative design justified the district court’s ruling to 

exclude testimony); Dhillon v. Crown Controls Corp., 269 F.3d 865, 869–70 (7th Cir. 

2001) (“We could identify a number of problems with the testimony these witnesses 

were prepared to offer, but the most glaring among them is the lack of testing, or 
9 

more generally the failure to take any steps that would show professional rigor in the 

assessment of alternative designs[.]”). We recognize “testing is not necessary in all 

instances to establish reliability under Daubert . . . .” Bitler, 400 F.3d at 1236. But 

the district court did not exclude Plaintiff’s expert’s opinion just because he did not 

test any door on the Raymond forklift himself. 

Second, Plaintiff asserts that disagreement between experts does not warrant 

the exclusion of either expert’s testimony. See Feliciano-Hill v. Principi, 439 F.3d 

18, 25 (1st Cir. 2006) (“The mere fact that two experts disagree is not grounds for 

excluding one’s testimony.”). Plaintiff argues that despite Raymond’s disagreement 

with Plaintiff’s expert’s opinions, Plaintiff’s expert did the requisite analysis and 

testing for a reliable and thus admissible opinion. But the district court did not 

exclude Plaintiff’s expert’s testimony because experts could differ on whether adding 

a door would on whole be a safer alternative design. The district court found 

Plaintiff’s expert’s opinions unreliable because 

Plaintiff’s expert fail[ed] to say how he considered [the various doors 

listed in his report], fail[ed] to identify any scientific or technical 

analysis he applied to each, or any of them, and offer[ed] no scientific 

support for his naked conclusion that each or any of them is safer than 

the Raymond design. 

ROA at 1919. For a jury to find an alternative design “safer” than the Raymond 

design, a comparative analysis must be possible. See Restatement (Third) of Torts, 

Prod. Liab. § 2 cmt. d (1997) (“Assessment of a product design in most instances 

requires a comparison between an alternative design and the product design that 

caused the injury . . . .”). And so Plaintiff had to offer at least one definitive
10 

competing design. See Allen, 8 F.3d at 1480–81 (“[I]n showing that the product can 

be made safer through the use of devices, a plaintiff must show that the devices exist 

and are not merely speculative.” (internal quotation marks and citation omitted)). A 

jury cannot compare the existing design to, essentially, anything and everything else. 

Plaintiff’s expert did not commit to any door design. True, Plaintiff’s expert 

included photos of some doors that exist in the real world in his expert report. But 

the district court did not abuse its discretion in concluding that existence of these 

doors in the world, with nothing more, was insufficient. See Guy, 394 F.3d at 327; 

Brown, 432 F.3d at 647–48; Dhillon, 269 F.3d at 869–70. 

Without commitment to any design, Plaintiff’s expert offered only sweeping 

opinions about doors in general. Plaintiff’s expert argued that he could put a door on 

the Raymond forklift, but he had never done so. He opined that a manufacturer 

should construct a door “out of a suitable material that would withstand the force of 

impact” but he did not say what constituted a suitable material. He contended that the 

“cost of providing such a rear door would be insignificant relative to the cost of the 

forklift” but he did not offer any numerical values aside from a projection for the cost 

of adding a latching rear door. But again, he never committed to a latching rear 

guard as an alternative design. So he offered this valuation only as a general 

example. 

Plaintiff’s expert also cited a 1991 study showing egress time only increased 

minimally when a manufacturer added a door to a forklift. But Plaintiff’s expert 

offered no evidence of which forklifts the 1991 study tested, under what 
11 

circumstances the study tested the forklifts, or what potential consequences exist 

because of the minimal increase in egress time. Plaintiff’s expert also cites a report 

showing egress time diminished where manufacturers added a spring loaded door to a 

forklift. Again, this data is not apparently specific to adding a spring loaded door to 

the Raymond forklift and Plaintiff’s expert fails to explain the circumstances under 

which the study tested the spring-loaded door. Even so, Plaintiff’s expert never 

committed to a spring loaded door as an alternative design. 

Other circuits have found expert testimony unreliable where the expert failed 

to test a proposed alternative design on the specific forklift at issue. See Dhillon, 269 

F.3d at 869–70 (holding that the experts’ methodology unreliable because 

“[a]lthough both experts wanted to assert that the truck design was defective because 

it did not include a rear door, neither expert ha[d] actually designed a model of a 

forklift truck with a rear door.” And neither “performed any tests of such a model to 

see if it is both economically feasible and just as safe or safer than the model without 

the door.”); Lawrence v. Raymond Corp., 501 F.App’x 515, 518–19 (6th Cir. 2012) 

(unpublished) (holding that because Plaintiff’s expert only tested his door design 

once and did not test it on the Raymond forklift, his test did not address the specific 

issues with his alternative design, “such as whether the latching-door design [was] 

compatible with the Raymond forklift; the impact a latching door would have on 

maintaining a Raymond forklift; or what effect, if any, a latching door would have on 

the forklift’s price.”). 
12 

The district court here permissibly found Plaintiff’s expert’s testimony 

unreliable because on this record, we cannot know what impact any alternative 

design may have on the Raymond forklift related to safety, control, performance, or 

price. And that is the problem. If Plaintiff’s expert wanted to advance multiple 

options, so be it. But however many options he advanced, they had to be designs 

supported by reliable methodology and capable of comparison. By not committing, 

Plaintiff’s expert made it impossible to compare the benefits and risks of any 

phantom design made of unknown materials, attached in unknown ways, with 

unknown safety and performance effects, at an unknown cost, to the Raymond 

design.4

 And as the district court properly noted, Utah law necessarily requires a 

comparative analysis to determine whether a safer, alternative design, practicable 

under the circumstances existed at the time of Plaintiff’s injury. So the district court 

did not abuse its discretion in excluding Plaintiff’s expert’s testimony. 

 Because the district court permissibly excluded Plaintiff’s expert’s testimony, 

Plaintiff did not prove an essential element of his claim—that a safer, feasible 

alternative design existed at the time of his injury. See Wankier v. Crown Equip. 

4

 Plaintiff tries to get around this issue on appeal by arguing that Raymond 

offers an optional spring-loaded door which a consumer may add to the Raymond 

forklift. So, Plaintiff argues, the Raymond door exists in real life and Raymond can 

fit the Raymond door to the Raymond forklift—problem solved. And although 

Plaintiff may wish that it committed to the Raymond optional door before the district 

court, Plaintiff cannot rewrite history. When counsel asked Berry in a hearing 

whether the Raymond option door was his alternative design, Berry responded that he 

would suggest a different type of door. But again, Berry did not commit to a 

definitive design or offer any evidence of the costs or benefits of adding that 

definitive design to the Raymond forklift. 
13 

Corp., 353 F.3d 862, 866–68 (10th Cir. 2003) (holding that under Utah law, a 

plaintiff must prove a safer, feasible alternative design). Accordingly, the district 

court properly granted summary judgment in Raymond’s favor. 

AFFIRMED.