Daycab Company, Inc. v. Prairie Technology, LLC; Big Truck Parts, LLC; William R. Osman; Wanda Osman

RECOMMENDED FOR PUBLICATION
Pursuant to Sixth Circuit I.O.P. 32.1(b)
File Name: 23a0099p.06
UNITED STATES COURT OF APPEALS
FOR THE SIXTH CIRCUIT
DAYCAB COMPANY, INC.,
Plaintiff-Appellant,
v.
PRAIRIE TECHNOLOGY, LLC; BIG TRUCK PARTS, LLC;
WILLIAM R. OSMAN; WANDA OSMAN,
Defendants-Appellees.
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No. 22-5625
Appeal from the United States District Court for the Eastern District of Tennessee at Knoxville.
No. 3:20-cv-00063—Travis Randall McDonough, District Judge.
Argued: March 16, 2023
Decided and Filed: May 11, 2023
Before: MOORE, CLAY, and STRANCH, Circuit Judges.
_________________
COUNSEL
ARGUED: Donald K. Vowell, THE VOWELL LAW FIRM, Knoxville, Tennessee, for
Appellant. Stephen C. Landon, CADWELL SANFORD DEIBERT & GARRY LLP, Sioux
Falls, South Dakota, for Appellees. ON BRIEF: Donald K. Vowell, THE VOWELL LAW
FIRM, Knoxville, Tennessee, for Appellant. Stephen C. Landon, Melissa R. Jelen, CADWELL
SANFORD DEIBERT & GARRY LLP, Sioux Falls, South Dakota, James R. McKoon,
MCKOON, WILLIAMS, ATCHLEY & STULCE, PLLC, Chattanooga, Tennessee, for
Appellees.
_________________
OPINION
_________________
CLAY, Circuit Judge. Plaintiff DayCab Company, Inc. appeals the district court’s entry
of summary judgment for Defendants Prairie Technology, LLC, Big Truck Parts, LLC, and
>

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William and Wanda Osman in Plaintiff’s case alleging trade dress infringement under Section
43(a) of the Lanham Act, 15 U.S.C. § 1125(a), and under the Tennessee Consumer Protection
Act, Tenn. Code Ann. § 47-18-104. For the reasons set forth below, we AFFIRM IN PART
and REVERSE IN PART the district court’s grant of summary judgment and REMAND for
further proceedings consistent with this opinion.
BACKGROUND
Factual Background
A. Plaintiff DayCab Company, Inc.
DayCab designs, manufactures, and sells conversion kits for tractor-trailer cabs that
convert a sleeper tractor—which has a compartment designed for long-haul driving, with a
sleeping unit for the driver—into a tractor that does not have a sleeper unit (a “daycab”).
DayCab’s founder, Marc Wagers, started his first conversion kit business in 1997 and has been
continuously involved in the design and manufacture of conversion kits since that time. Wagers
stated that he created the first Peterbilt extended-cab conversion kits on the market, which he
termed “Fat Albert” models. In 2004, DayCab introduced “XL” conversion kits for two types of
Peterbilt trucks, the Unibilt and the Ultracab models. DayCab spent significant time and money
marketing its products and succeeded in growing sales of its products.
Wagers’ goals in designing the XL models were to: (1) “allow more room in the cab for
the driver and/or for storage of more equipment than the flat-panel unit provided;” (2) “allow for
the installation or use of an air-ride system or similar equipment, in some cases;” and (3) “be
distinctive in appearance so it would be recognizable by consumers.” Marc Wagers Decl., R.
188, ¶ 11, Page ID #2298. The depth of the conversion kit, an additional 5.375 inches, “allows
additional room inside the cab” and the slant-back design of the conversion panel “allows space
for the attachment of air-ride equipment.” DayCab’s Resps. to Interrogs., R. 199-2, PageID
#3007. Wagers attested:
I could have designed the XL models in any number of additional ways, or with
any number of different looks, and the design I ended up with was my choice as a
matter of personal taste. I considered and decided against several other possible

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designs, including designs with different angles, curves, tapers, lines, profile and
appearance, but finally settled on what became the final model because I liked the
way that it looked.
Wagers Decl., R. 188, ¶ 11, Page ID #2298.
Wagers stated that he “carefully selected” the “angles, curves, tapers, lines, profile and
appearance” of the DayCab conversion kit “with the aim of making a very distinctive and
attractive kit,” but “any number of other angles, curves, tapers, lines, profile and appearance”
would have also served as a Peterbilt conversion product. Id., ¶ 24, Page ID #2306. Wagers
acknowledged it was “necessary to leave 5–6 inches of flat surface or clearance along the bottom
edge to allow for the attachment” of the shock absorbers for an air-ride system, but stated that it
was not necessary to use the “slant-back” design of 144 degrees. Id., ¶ 14–16, Page ID #2301–
2302. Another angle could be used to accommodate the air-ride system. As for the particular
144 degree angle of the slant-back that he used, Wagers attested that it occurred by happenstance
because the engineer who made the conversion kit mold used the exact angle that Wagers had
included in his hand-drawn design. When designing the particular dimensions of the depth and
radius of the design, Wagers stated that they arose when he asked his engineer to make the
design look “less pointy,” which resulted in the radius of 1.5 inches and the depth of 5.375
inches. Id., ¶ 20 & 21, Page ID #2303–2304.
Further demonstrating that the Peterbilt conversion product can be designed in a number
of ways, Wagers attested that competitor companies manufacture functional Peterbilt conversion
kits that are “completely different from the DayCab design and appearance.” Id., ¶ 17–18, Page
ID #2302–2303. Wagers also presented two alternative designs created by DayCab personnel to
show that it was possible to create functional conversion kits different from the DayCab model.
In a second declaration, Wagers attested that the only requirement for manufacturability
is that the top of the fiberglass mold used for manufacturing the conversion kits must be slightly
larger at the top than at the bottom. Wagers also attested that the exterior coating of soft-sanding
gelcoat comes in numerous colors other than gray, none of which is more or less difficult to sand
or paint than another.

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B. Defendants Prairie Technology, LLC, Big Truck Parts, LLC, and the Osmans
William Osman is an owner of both Big Truck Parts and Prairie Technology. He is
married to Wanda Osman. William Osman began making conversion kits in 1998. Shortly after,
Osman obtained a utility patent for a panel used to convert a sleeper truck cab into a day cab.
In 2015, Osman started Prairie Technology, LLC and Big Truck Parts, LLC. Since then,
William and Wanda Osman have conducted business through those entities and not in their
personal capacities. Prairie Technology designs and manufactures conversion kits, and Big
Truck Parts sells them. The price of the kits ranges from $1,325 to $2,060. Each kit is
manufactured and sold with an identification card with Prairie Technology’s logo embedded in
the fiberglass and is shipped in a box bearing Prairie Technology’s logo. Additionally, Big
Truck Parts includes a placard bearing its name and logo to be placed on the driver’s side door of
reconfigured cabs. Big Truck Parts and Prairie Technology named their conversion-kit products:
“Cousin Albert,” “Uncle Albert,” and “Fat Boy.” Wagers Decl., R. 188, ¶ 34 & 36, Page ID
#2312 & 2314; Prairie Technology Invoices, R. 189, Page ID #2382–2390.
C. Dr. George Wandling’s Expert Opinion
Dr. George Wandling prepared a preliminary report in anticipation of testifying as an
expert defense witness. Dr. Wandling is a licensed professional engineer who received his
doctorate in mechanical engineering from Iowa State University in 2000 and has more than forty
years of mechanical engineering experience. In his report, Dr. Wandling stated that he based his
opinions on records, data, and materials provided to him, an inspection of Prairie Technology
conversion kits for Unibilt and Ultracab Peterbilt trucks, DayCab kits for Ultracab trucks, and an
interview with Osman.
Dr. Wandling conducted a laser analysis to determine the measurements of Prairie
Technology’s Ultracab and Unibilt conversion panels and of DayCab’s Ultracab conversion
panel. DayCab did not provide a Unibilt conversion panel to Dr. Wandling for analysis. Dr.
Wandling’s report stated:
The Prairie Technology and Daycab Ultracab conversion panels are not identical.
The Prairie Technology Ultracab panel can be physically placed inside the

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Daycab panel. The depth of the panel is a function of the Peterbilt seat location
and the seat’s extension beyond the rear of the cab structure. If the Peterbilt seat
did not extend beyond the conversion panel mounting surface, the panel would be
flat. The use of a radius rather than a sharp corner at panel edges is functionally
required for manufacturability of the panel, and the radii used by Prairie
Technology and Daycab are distinctly different. The sloped bottom surface of the
panel functionally provides clearance for the Peterbilt suspension hardware,
facilitates removal of the panel from the mold, and has an[] acute angle of
approximately 36 degrees. The gray color of the panel is a function of the gel
coat used in the manufacture of the panel and each panel is ultimately painted to
the specification of the purchaser.
Wandling Report, R. 199-2, Page ID #2951.
At the conclusion of his report, Dr. Wandling provided the following opinions: (1) that
Osman’s patent for a panel was issued before DayCab sold its first Peterbilt kit; (2) that “DayCab
has not produced any evidence” that its kits were “designed and manufactured” prior to Prairie
Technology’s; (3) that the DayCab and Prairie Technology kits “are not identical;” (4) that
Defendants “did not take a wax or plaster or similar impression of DayCab’s Ultracab conversion
panel nor intentionally make an exact or near-exact replica of . . . DayCab’s Ultracab panel using
other means;” (5) each company’s “panel’s depth, top body radius, lower body angle,
flange/body radius” and color are functional; and (6) DayCab may have infringed on Osman’s
patent. Id., Page ID #2955.
Procedural Background
DayCab sued Prairie Technology, LLC and Big Truck Parts, LLC in Tennessee state
court and Defendants removed the case to federal court based on diversity jurisdiction. In the
operative second amended complaint, DayCab named William and Wanda Osman as defendants
in addition to Prairie Technology and Big Truck Parts. DayCab asserted claims under Section
43(a) of the Lanham Act, 15 U.S.C. § 1125(a), and under the Tennessee Consumer Protection
Act, Tenn. Code Ann. § 47-18-104, for trade dress infringement, seeking monetary and
injunctive relief. Prairie Technology and Big Truck Parts counterclaimed for a declaratory
judgment that DayCab’s trade dress is functional and that Defendants have not infringed on
DayCab’s trade dress or trademark.

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After discovery closed, DayCab filed a motion under Daubert v. Merrell Dow
Pharmaceuticals, Inc., 509 U.S. 579 (1993), to exclude the testimony of Defendants’ expert,
arguing that Dr. Wandling’s opinions were not based on any scientific, technical, or other
specialized knowledge, and that the opinions would not be helpful to the trier of fact. The
district court granted the motion in part, excluding the first, second, and sixth opinions of Dr.
Wandling because they would not be helpful to the jury. The court excluded the fourth opinion
because Dr. Wandling was not qualified to opine on Osman’s intention. However, the district
court did not exclude Dr. Wandling’s third opinion regarding the similarity of the two conversion
kits or his fifth opinion regarding the functionality of the two conversion kits. It reasoned that
Dr. Wandling was qualified to testify on those matters based on his years of engineering
experience, examination of the products, and his statement in his report of why the trade dress
was functional. On appeal, DayCab challenges the district court’s failure to exclude Dr.
Wandling’s opinion regarding functionality, arguing that Dr. Wandling lacked the qualifications
necessary to render an expert opinion on the subject.
In addition, the parties filed cross discovery motions regarding the testimony of Marc
Wagers. DayCab moved to supplement its expert disclosure by adding Wagers as an expert
witness, but the district court denied the motion because the deadline for disclosing experts had
passed. For their part, Defendants moved to strike certain portions of Wagers’ testimony on the
grounds that it constituted undisclosed and improper expert testimony. The district court granted
in part Defendants’ motion, striking four portions of Wagers’ testimony that it determined were
impermissible legal conclusions, speculative, or irrelevant. On appeal, DayCab does not
challenge the district court’s ruling excluding portions of Wagers’ testimony, nor does it rely on
the stricken portions of Wagers’ testimony as evidence.
The parties filed cross motions for summary judgment. Defendants moved on the basis
that DayCab would not be able to prove any of the three essential elements of its trade dress
claim, namely: nonfunctionality, secondary meaning, and likelihood of confusion. See
Groeneveld Transp. Efficiency, Inc. v. Lubecore Int’l., Inc., 730 F.3d 494, 503 (6th Cir. 2013).
Defendants also argued that DayCab’s claims were time-barred. DayCab moved for partial
summary judgment on its trade dress infringement claim.

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Ultimately, the district court denied summary judgment to DayCab and granted summary
judgment to Defendants on their corresponding counterclaim for declaratory judgment. The
district court held that the undisputed evidence showed that DayCab’s asserted trade dress for its
conversion kits was functional and therefore not protectable. The court did not reach the issues
of secondary meaning, likelihood of confusion, or the time bars to DayCab’s claims. DayCab
timely appealed.
DISCUSSION
Standard of Review
“We review de novo a district court’s grant of summary judgment in a trade dress claim
case.” Leapers, Inc. v. SMTS, LLC, 879 F.3d 731, 735 (6th Cir. 2018) (citing Gibson Guitar
Corp. v. Paul Reed Smith Guitars, LP, 423 F.3d 539, 546 (6th Cir. 2005)). Summary judgment
is proper when “there is no genuine dispute as to any material fact and the movant is entitled to
judgment as a matter of law.” Fed. R. Civ. P. 56(a). “A dispute of a material fact is genuine so
long as ‘the evidence is such that a reasonable jury could return a verdict for the non-moving
party.’” Kirilenko-Ison v. Bd. of Educ., 974 F.3d 652, 660 (6th Cir. 2020) (quoting Jackson v.
VHS Detroit Receiving Hosp., Inc., 814 F.3d 769, 775 (6th Cir. 2016)). This Court must draw all
reasonable inferences in favor of the non-moving party. Leapers, 879 F.3d at 735.
Analysis
I. Trade Dress under the Lanham Act1
Section 43(a) of the Lanham Act protects from infringement the unregistered “trade
dress” of a product. 15 U.S.C. § 1125(a)(3); Wal–Mart Stores, Inc. v. Samara Bros., 529 U.S.
205, 210 (2000); Groeneveld, 730 F.3d at 503. This Court has held that:
“‘Trade dress’ refers to ‘the image and overall appearance of a product.’ It
embodies ‘that arrangement of identifying characteristics or decorations
connected with a product, whether by packaging or otherwise, [that] make[s] the
1Because we find that DayCab’s state law claim for unfair or deceptive acts or practices under the
Tennessee Consumer Protection Act, Tenn. Code Ann. § 47-18-104(b)(1), (2), and (3) is barred by the applicable
statute of limitations, we need not review the merits of the claim. See infra, Section II (2).

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source of the product distinguishable from another and . . . promote[s] its sales.’”
Trade dress “‘involves the total image of a product and may include features such
as size, shape, color, or color combinations, texture, graphics, or even particular
sales techniques.’”
Abercrombie & Fitch Stores, Inc. v. Am. Eagle Outfitters, Inc., 280 F.3d 619, 629 (6th Cir. 2002)
(first quoting Ferrari v. Roberts, 944 F.2d 1235, 1239 (6th Cir. 1991), then quoting Two Pesos,
Inc. v. Taco Cabana, Inc., 505 U.S. 763, 764 n.1 (1992)) (alterations in Abercrombie).
In this case, DayCab seeks to protect the overall design of its conversion kit panel,
including the panel’s angles, lines, tapers, curves, and profile. Specifically, DayCab asserts the
following as its protectable trade dress: (1) the slant-back design with specific angles and radii,
including a 144 degree slant towards the cab and rolled edges with radii of 1.5 inches; (2) the
depth of 5.375 inches; (3) the rounded edges with specific angles and radii; and (4) the gray
color.
To prevail on its claim for the infringement of its product design trade dress under the
Lanham Act, DayCab must show that its allegedly infringed product design
is: “(1) nonfunctional, (2) has acquired secondary meaning, and (3) is confusingly similar to the
allegedly infringing product design.” Groeneveld, 730 F.3d at 503. The first two elements
concern protectability—that is, that DayCab’s asserted trade dress is capable of Lanham Act
protection—and the third element requires a showing that Defendants have infringed on the trade
dress. Abercrombie, 280 F.3d at 629.
1. Nonfunctionality
The district court granted summary judgment to Defendants because it determined that no
reasonable juror could find that DayCab’s product design was nonfunctional. We conclude that
the district court erred in its determination. DayCab has presented a genuine dispute of material
fact regarding the nonfunctionality element of its trade dress claim.
The nonfunctionality requirement “channel[s] the legal protection of useful designs from
the realm of trademark to that of patent” to ensure “that the high public costs of monopoly are
not imposed without an assurance that the design satisfies the rigorous requirements of
patentability[.]” Groeneveld, 730 F.3d at 508. A product design is functional “if it is essential to

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the use or purpose of the article or if it affects the cost or quality of the article.” Inwood Lab’ys,
Inc. v. Ives Lab’ys, Inc., 456 U.S. 844, 850 n.10 (1982). “Evidence that a product design is
purely ‘ornamental, incidental, or arbitrary’ can be evidence of an absence of functionality.”
Leapers, 879 F.3d at 736 (quoting TrafFix Devices, Inc. v. Mktg. Displays, Inc., 532 U.S. 23, 30
(2001)). However, a design may have incidental functionality if it turns out to have functional
value despite an original aesthetic intent. See Inwood, 456 U.S. at 850 n.10. Further, evidence
of aesthetic intent alone may be insufficient to show that a feature is nonfunctional, as “some
products function based on their aesthetic properties through so-called ‘aesthetic functionality,’”
meaning a design that “communicates the use, purpose, cost, or quality of the product in a way
that competitors cannot avoid replicating without incurring costs.” Leapers, 879 F.3d at 737
(quoting Abercrombie, 280 F.3d at 642). “But ‘there are few aesthetic designs that are so
fundamental to an industry that competitors cannot fairly compete without free use of [them].’”
Leapers, 879 F.3d at 737 (quoting 1 McCarthy on Trademarks and Unfair Competition § 7:81
(5th ed.)). Accordingly, “a party’s initial burden to show that a design lacks aesthetic
functionality is not substantial; the plaintiff need only show that the design is not a competitive
necessity such that ‘exclusive use . . . would put competitors at a significant non-reputation
related disadvantage.’” Id. (quoting TrafFix, 532 U.S. at 32–33).
Defendants contend that DayCab’s product design is not protectable because it is
functional. Based on the testimony of the operator of a competitor company and an installer of
the conversion kits, Defendants argue that the function of the conversion kit panel is to cover the
opening created by removing the sleeper berth and to create more room in the truck cab.
Defendants also point to DayCab’s statements on its website about the functionality of its
product design and to DayCab’s interrogatory responses stating that the slant-back feature
“allows for the attachment of air-ride equipment” and that the depth “allows additional room
inside the cab.” DayCab’s Resps. to Interrogs., R. 199-2, Page ID #3007.
However, while a product may serve a function, that does not render its specific features
necessarily functional. For instance, in Leapers, the Court considered a unique “knurling”
pattern which the plaintiff used to add texture to adjustable rifle scopes. Leapers, 879 F.3d at
733. The Court held that while knurling was a functional component of the rifle scope, a jury

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could reasonably conclude that the knurling design that the plaintiff used on its rifle scopes was
“purely ornamental and therefore nonfunctional.” Id. at 738. It noted that the variety of patterns
that could be applied to an adjustment knob was “effectively unlimited” and there was no
“scarcity” or “depletion” of available designs. Id. at 739. Similarly, in this case, while the
conversion kit panel serves the general function of covering the opening in a truck cab, there
remains a genuine dispute of material fact whether the specific design of the panel constitutes
protectable trade dress, as that design is not the only design available.
In his declaration, Wagers stated that he created the DayCab conversion kit panel design
as a “matter of personal taste,” that he settled on the final design by “happenstance,” because he
“liked the way that it looked,” and that the exact angles, depth, and radii arose from Wagers’
finetuning of the panel’s appearance. Wagers Decl., R. 188, ¶ 11, Page ID #2298. These
statements by Wagers show his aesthetic intent in designing and configuring the panel. That
evidence tends to show that the product’s design is “ornamental, incidental, or arbitrary,” which
in turn tends to show the absence of functionality. Leapers, 879 F.3d at 736. When aesthetic
intent is established, the relevant inquiry is whether the design is functional so that “competitors
cannot avoid replicating without incurring costs ‘not to copy but to design around.’” Id. at 737
(quoting Abercrombie, 280 F.3d at 642-43). Relevant to this inquiry, DayCab presented
evidence of designs for functional conversion kit panels that do not replicate DayCab’s design,
including designs used by two competitor companies and new designs created by DayCab
personnel.
Defendants argue that we need not, and should not, consider this evidence of alternative
functional designs based on the legal principle that once “a trade dress is found to be functional,
the mere fact that there are other non-infringing designs which would serve the same functional
purpose is no defense to functionality.” Gen. Motors Corp. v. Lanard Toys, Inc., 468 F.3d 405,
416 (6th Cir. 2006); see also TrafFix, 532 U.S. at 33 (where a product design is functional under
the Inwood Laboratories test, “[t]here is no need . . . to engage . . . in speculation about other
design possibilities . . . which might serve the same purpose”). In contrast to these two cases
where the design was functional, regardless of other methods in providing that same function, in
this case DayCab argues that the design serves no functional purpose at all. The existence of

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alternative designs is relevant to the functionality determination because they support DayCab’s
contention that Wagers designed the panel with aesthetic intent and that its resulting features are
ornamental rather than functional.
Additionally, Defendants argue that they are entitled to summary judgment because of
Dr. Wandling’s expert opinion that DayCab’s product design is functional. Dr. Wandling opined
that the “panel’s depth, top body radius, lower body angle, flange/body radius” and color were
functional features. Wandling Report, R. 199-2, Page ID #2955. He based this opinion on his
conclusions that the depth of the panel was necessary to allow the seat to extend backwards; that
the slant-back angle of 144 degrees created space for the air-ride system and facilitated removal
of the panel from the mold during manufacturing; the rounded edges were “required for
manufacturability of the panel;” and that the gray color was a function of the gelcoat used in the
manufacture of the panel. Id., Page ID #2951.
However, DayCab presented evidence that contradicts Dr. Wandling’s opinion in the
form of a declaration by Wagers. In his declaration, Wagers stated that the only requirement for
manufacturability was that the top of the fiberglass mold used for manufacturing the conversion
kits be slightly larger at the top than at the bottom of the mold, and that it was therefore not
necessary for the panel to have a slant-back with the exact angle of 144 degrees. Similarly,
Wagers stated it is not essential to use the exact angle of 144 degrees to allow space for the
installation of the air-ride system. Further, regarding the color of the exterior gelcoat, Wagers
stated that gray was not the only gelcoat color available, and that no color is more conducive to
sanding or painting than another color. Because we draw all reasonable inferences in favor of
the non-moving party, and Wagers’ declaration contradicts Dr. Wandling’s opinion, Defendants
are not entitled to summary judgment and lack sufficient evidence to meet their burden. See
Leapers, 879 F.3d at 735.
The parties have presented conflicting evidence regarding the functionality of DayCab’s
conversion kit panel. Accordingly, we conclude that genuine issues of material fact remain
regarding the nonfunctionality element of DayCab’s trade dress claim. The district court erred in
granting summary judgment to Defendants on this basis.

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2. Secondary Meaning
Next, Defendants contend that we may affirm the district court’s grant of summary
judgment on the alternative basis that no reasonable juror could conclude that DayCab’s panel
design has acquired secondary meaning. However, based on the evidence DayCab presented at
summary judgment, we conclude that DayCab has raised a genuine dispute of material fact on
the element of secondary meaning.
Secondary meaning “serves to identify the product with its manufacturer or source.”
TrafFix, 532 U.S. at 28. “To establish secondary meaning, a manufacturer must show that, in the
minds of the public, the primary significance of a product feature or term is to identify the source
of the product rather than the product itself.” Inwood Lab’ys, 456 U.S. at 851 n.11. “This Court
applies a seven-factor test to determine whether secondary meaning exists in a trade dress:
(1) direct consumer testimony, (2) consumer surveys, (3) exclusivity, length, and manner of use,
(4) amount and manner of advertising, (5) amount of sales and number of customers,
(6) established place in the market, and (7) proof of intentional copying.” Lanard Toys, 468 F.3d
at 418.
To start with the last factor, proof of intentional copying, DayCab posits that a juror
could reasonably find that Prairie Technology intentionally copied DayCab’s conversion panel
design. In support, DayCab points to the testimony of Arvil Lewis, the owner of competitor
FiberTech, who stated in regard to the Prairie Technology conversion kits that: “if you see them
going down the road, I personally cannot tell one from the other when they’re mounted on the
truck because the design is very, very similar to DayCab.” Lewis Dep., R. 189, Page ID #2407.
DayCab also points to Wagers’ testimony that: “[w]hen I see them on the road, I cannot tell
whether it is our product or the Prairie Technology/Big Truck Parts product unless I get very
close to them.” Wagers Decl., R. 188, ¶ 39, Page ID #2315. Finally, DayCab points to Dr.
Wandling’s testimony that the Prairie Technology panel “can physically be placed inside the
DayCab panel,” as evidence showing that the panels are similar.
In response, Defendants contend that no intentional copying occurred. Defendants point
to William Osman’s statement that his panel design was informed by the structural frame of the

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Peterbilt truck cab, by customer feedback seeking more space in the truck cab, and by the
requirements for manufacturing. Defendants also point to Dr. Wandling’s expert testimony that
the DayCab and Prairie Technology conversion panels are “not identical and are distinctly
different in overall width, height, body radius, corner radius, window size, and mounting
methodology.” Wandling Report, R. 199-2, Page ID #2951. Defendants further argue that Dr.
Wandling’s statement that the Prairie Tech panel “can physically be placed inside the DayCab
panel” referred to his opinion that the Prairie Technology panel was smaller than, not identical
to, the DayCab panel. Id.
Defendants present evidence that contradicts DayCab’s theory of intentional copying, and
offer a different interpretation of Dr. Wandling’s opinion that supports their position. However,
given the evidence DayCab has presented, the record before us reveals a dispute of fact on the
intentional copying factor. This supports a determination that there is a genuine issue of material
fact about secondary meaning, as “evidence of intentional copying shows the strong secondary
meaning of [a product] because ‘[t]here is no logical reason for the precise copying save an
attempt to realize upon a secondary meaning that is in existence.’” Abercrombie, 280 F.3d at
639 (citing Ferrari, 944 F.2d at 1239).
In addition, relevant to the fifth factor, the amount of sales and number of customers,
DayCab argues that it spent significant money on advertising which resulted in an increase in
sales. DayCab points to Wagers’ testimony that: “[m]any callers to DayCab have told me that
they were calling because of both the print advertising and/or because of our appearances at the
trade shows, that they recognize the distinctive slant-back design, and that when they see that
design, they think of the DayCab Company.” Wagers Decl., R. 188, ¶ 54, Page ID #2322–2323.
This is additional evidence supporting a determination that a genuine dispute of fact exists
regarding the secondary meaning of DayCab’s conversion kit panel.
Regarding the remaining factors that we consider in determining whether secondary
meaning exists, the parties have not set forth arguments or identified evidence that relate to them.
However, “[n]o single factor is determinative and every one need not be proven.” Herman
Miller, Inc. v. Palazzetti Imports & Exports, Inc., 270 F.3d 298, 312 (6th Cir. 2001) (citing
Centaur Commc’ns, Ltd. v. A/S/M Commc’ns, Inc., 830 F.2d 1217, 1222 (2d Cir. 1987)).

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DayCab has set forth a genuine dispute of fact on two of the factors, including evidence showing
intentional copying, which tends to show strong secondary meaning. See Abercrombie, 280 F.3d
at 639. Accordingly, we conclude that Defendants are not entitled to summary judgment based
on the secondary meaning element.
3. Likelihood of Confusion
Finally, Defendants contend that we may affirm the district court’s grant of summary
judgment on the alternative basis that no reasonable jury could conclude that there is a likelihood
of confusion between the products. However, based on the evidence DayCab presented at
summary judgment, we conclude that DayCab has raised a genuine dispute of material fact on
the element of likelihood of confusion.
The test for likelihood of confusion is whether an ordinary consumer would confuse the
products at issue, incorrectly assuming that the products derive from one source rather than from
different sources. See, e.g., Daddy’s Junky Music Stores, Inc. v. Big Daddy’s Family Music
Ctr., 109 F.3d 275, 280 (6th Cir. 1997). The “‘general concept underlying the likelihood of
confusion is that the public believe that the [mark or dress] owner sponsored or otherwise
approved the use of the trademark’ or trade dress.” Abercrombie, 280 F.3d at 645 (quoting
Carson v. Here’s Johnny Portable Toilets, Inc., 698 F.2d 831, 834 (6th Cir. 1983)). Whereas
nonfunctionality and secondary meaning are required to show protectability—that is, that the
plaintiff’s trade dress is capable of Lanham Act protection in the first place—likelihood of
confusion is required to show that the trade dress has in fact been infringed by the
defendant. Abercrombie, 280 F.3d at 629.
We have enumerated:
eight factors to consider in determining whether the trade dresses of competing
products present a sufficient likelihood of confusion: “(1) strength of the
plaintiff’s [trade dress]; (2) relatedness of the goods; (3) similarity of the [trade
dresses]; (4) evidence of actual confusion; (5) marketing channels used; (6) likely
degree of purchaser care; (7) defendant’s intent in selecting the [trade dress];
(8) likelihood of expansion of the product lines.”

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Groeneveld, 730 F.3d at 509 (quoting Frisch’s Restaurant, Inc. v. Shoney’s Inc., 759 F.2d 1261,
1264 (6th Cir. 1985)).
Relevant to the third factor, similarity of the trade dresses, DayCab argues that the
similarity of the panels alone demonstrates the likelihood of confusion. DayCab also points to
Lewis’ and Wagers’ testimony that they could not tell the panels apart. DayCab argues that if
Lewis and Wagers, who operate businesses in this industry, cannot tell the panels apart, then a
jury could reasonably conclude that a consumer likewise would not be able to tell one from the
other.
Relevant to the fourth factor, actual confusion, DayCab presented evidence of actual
confusion between the products. For instance, Wagers attested that that he has fielded
“numerous inquiries” from customers interested in purchasing a “Fat Boy” even though DayCab
sells only a product by the name “Fat Albert,” and that the inquiries began in 2010 or 2011 after
William Osman began marketing his conversion kit as the “Fat Boy.” Wagers Decl., R. 188, ¶
63, Page ID #2327. As recent examples, DayCab points to two customer inquiries about
purchasing a “fat boy” conversion kit, one from 2020 and one from 2022. DayCab argues that
Defendants’ use of a similar product design and similar product name shows that Defendants
intended to create, and have created, market confusion. Evidence of actual confusion is
“undoubtedly the best evidence of likelihood of confusion.” Daddy’s Junky Music, 109 F.3d at
284 (quoting Wynn Oil Co. v. Thomas, 839 F.2d 1183, 1188 (6th Cir. 1988)).
Defendants argue that the sixth factor, likely degree of purchaser care, weighs in their
favor. Ordinarily, the benchmark for assessing the likelihood of confusion is the ordinary
consumer, but, as described in our Circuit:
“[W]hen a buyer has expertise or is otherwise more sophisticated with respect to
the purchase of the services at issue, a higher standard [of consumer confusion] is
proper. Similarly, when services are expensive or unusual, the buyer can be
expected to exercise greater care in her purchases. When services are sold to such
buyers, other things being equal, there is less likelihood of confusion.”
Daddy’s Junky Music, 109 F.3d at 285 (quoting Homeowners Group, Inc. v. Home Marketing
Specialists, Inc., 931 F.2d 1100, 1111 (6th Cir. 1991)). Defendants argue that the conversion kits
are purchased only by industry professionals with significant care and research because the kits

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are purchased directly from their suppliers, as opposed to sold in stores, and cost between $1,325
and $2,060. Further, Defendants argue that the Prairie Technology conversion kits’ packaging,
components, and related advertising are clearly marked with Prairie Technology’s and Big Truck
Parts’ names and logos. Given the sophistication of the purchasers of conversion kits, this factor
weighs in Defendants’ favor.
Regarding the remaining factors, the parties have not set forth arguments or identified
evidence that relate to them. However, these factors are guides rather than rigid requirements to
determine whether the trade dresses of competing products present a sufficient likelihood of
confusion, and the helpfulness of any particular factor depends on the circumstances present in
the case. Daddy’s Junky Music, 109 F.3d at 280; see also, e.g., Abercrombie, 280 F.3d at 646–
48 (considering only one of the eight factors, similarity of the trade dress, and ruling for the
defendant on that basis). In this case, DayCab has presented evidence that weighs in its favor on
two of the factors relevant to the likelihood of confusion analysis. Weighing DayCab’s evidence
against Defendants’ evidence, as well as balancing the factors to determine whether the products
present a sufficient likelihood of confusion, is the province of the jury. Accordingly, we
conclude that Defendants are not entitled to summary judgment based on the likelihood of
confusion element.
II. Remaining Issues
1. Admissibility of Dr. Wandling’s Opinion
DayCab contends that the district court erred by denying its motion to exclude Dr.
Wandling’s testimony related to functionality. We review a district court’s decision to admit
expert testimony for abuse of discretion. Osborn v. Griffin, 865 F.3d 417, 452 (6th Cir. 2017).
“A district court abuses its discretion if it bases its ruling on an erroneous view of the law or a
clearly erroneous assessment of the evidence.” United States v. LaVictor, 848 F.3d 428, 440 (6th
Cir. 2017) (quoting Best v. Lowe’s Home Cntrs., Inc., 563 F.3d 171, 176 (6th Cir. 2009)).
In order for an expert witness’s opinion to be admissible under Rule 702 of the Federal
Rules of Evidence, (1) the witness must be qualified by “knowledge, skill, experience, training,
or education;” (2) the testimony must be relevant, meaning that it will assist “the trier of fact to

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understand the evidence or to determine a fact in issue;” and (3) the testimony must be reliable,
as assessed by its factual basis and the sufficiency of its principles and methods. Bradley v.
Ameristep, Inc., 800 F.3d 205, 208 (6th Cir. 2015) (quoting United States v. Cunningham, 679
F.3d 355, 379-80 (6th Cir. 2012)); see also In re Scrap Metal Antitrust Litig., 527 F.3d 517, 528–
29 (6th Cir. 2008).
We conclude that the district court did not abuse its discretion by declining to exclude Dr.
Wandling’s opinion on functionality. DayCab argues that Dr. Wandling lacks the necessary
qualifications because he does not have specific experience in fiberglass manufacturing,
conversion kits, or truck body work. Further, DayCab contends that Dr. Wandling based his
opinion only on what Osman told him. However, Dr. Wandling is a licensed professional
mechanical engineer with extensive experience in the fields of design, product development,
manufacture and servicing of machines, and in providing professional engineering services.
Further, Dr. Wandling clarified that his opinion, while based in part on an interview with Osman,
was also based on his education and experience, and on his analysis of the conversion kits. The
district court did not abuse its discretion in determining that Dr. Wandling’s credentials and
experience, and his independent analysis of the conversion kits, qualify him to give expert
testimony about the functionality of the conversion panel features.
2. Statute of Limitations
As an alternative basis for affirming the district court’s grant of summary judgment on
DayCab’s state law claim under the Tennessee Consumer Protection Act, Defendants contend
that this claim is barred by the statute of limitations. DayCab asserted a state law claim for
unfair or deceptive acts or practices under the Tennessee Consumer Protection Act, Tenn. Code
Ann. § 47-18-104(b)(1), (2), and (3). The Act provides that any person who suffers certain
injuries as a result of an unfair or deceptive act or practice described in § 47-18-104(b) may
bring an action to recover damages. Tenn. Code Ann. § 47-18-109. The Act provides that
“[a]ny action commenced pursuant to § 47-18-109 shall be brought within one (1) year from a
person’s discovery of the unlawful act or practice.” Id. § 47-18-110. Defendants contend that
DayCab discovered Prairie Technology’s alleged trade dress infringement more than one year
before DayCab initiated this action.

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DayCab does not respond to this argument on appeal, nor did DayCab respond to this
argument before the district court. Accordingly, DayCab has forfeited this issue. See Hood v.
Tenn. Student Assistance Corp. (In re Hood), 319 F.3d 755, 760 (6th Cir. 2003). We conclude
that DayCab’s state law claim under the Tennessee Consumer Protection Act is barred by the
applicable statute of limitations. On this alternative basis, we affirm the district court’s grant of
summary judgment to Defendants on DayCab’s state law claim.
3. Doctrine of Laches
Finally, Defendants contend that the doctrine of laches bars DayCab’s trade dress claim
under the Lanham Act. Because the district court granted summary judgment in favor of
Defendants on the merits, it did not decide the question of laches. However, because the issue
was briefed before the district court and before this Court, we will consider the issue on appeal.
The Lanham Act does not contain a statute of limitations. Accordingly, whether a claim
is barred due to a delay in filing depends on the equitable doctrine of laches. Kehoe Component
Sales Inc. v. Best Lighting Prods., Inc., 796 F.3d 576, 584 (6th Cir. 2015). “Laches is the
negligent and unintentional failure to protect one’s rights.” Id. (quoting Nartron Corp. v.
STMicroelectronics, Inc., 305 F.3d 397, 408 (6th Cir. 2002)). “Unlike statutes of
limitations, laches is not a mere matter of time; but principally a question of the inequity of
permitting the claim to be enforced.” Ford Motor Co. v. Catalanotte, 342 F.3d 543, 550 (6th
Cir. 2003). A party asserting laches must show: “(1) lack of diligence by the party against
whom the defense is asserted, and (2) prejudice to the party asserting it.” Nartron, 305 F.3d at
408.
A plaintiff’s delay in asserting its rights is presumptively reasonable as long as an
analogous state statute of limitations has not elapsed. Id. In contrast, a delay beyond the
analogous limitations period “is presumptively prejudicial and unreasonable.” Id. “For the
Lanham Act claim in this case, the relevant benchmark is the one-year limitations period
prescribed . . . by the Tennessee Consumer Protection Act.” See Am. Addiction Cntrs., Inc. v.
Nat’l Ass’n of Addiction Treatment Providers, 515 F. Supp. 3d 820, 838 (M.D. Tenn. 2021)
(citing Johnny’s Fine Foods, Inc. v. Johnny’s Inc., 286 F. Supp. 2d 876, 881 (M.D. Tenn. 2003))

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(holding one-year Tennessee Consumer Protection Act statute of limitations applies to Lanham
Act trade dress infringement claims).
DayCab delayed filing its action beyond the analogous one-year limitations period. For a
Lanham Act claim, the laches period begins to run when the plaintiff has “actual or constructive
knowledge of the alleged infringing activity.” Narton, 305 F.3d at 408 (quoting Dana Corp. v.
IPC Ltd. Partnership, 674 F.Supp. 581, 583 (E.D. Mich. 1987)). Wagers became aware of
Defendants’ allegedly infringing products in the market around 2012. Wagers and other DayCab
personnel became aware of Defendants’ listing and sale of the allegedly infringing products on
their websites in 2015 or 2016. However, DayCab did not file this action until 2020. Therefore,
DayCab filed beyond the analogous limitations period and its claim is subject to a presumption
that the delay in filing was unreasonable and prejudicial.
To excuse its delay, DayCab relies on the doctrine of progressive encroachment. The
doctrine of progressive encroachment excuses delay, allowing a plaintiff to wait to bring an
action until the “likelihood of confusion looms large.” Kellogg Co. v. Exxon Corp., 209 F.3d
562, 570–71 (6th Cir. 2000) (quoting Sara Lee Corp. v. Kayser-Roth Corp., 81 F.3d 455, 462
(4th Cir. 1996)). This doctrine allows a plaintiff to demonstrate that “although it might have
been justified in bringing suit earlier but did not, certain factors now exist that have prompted it
to do so.” Id. at 571. As we have explained:
Progressive encroachment is relevant in assessing whether laches or acquiescence
may be used to bar a plaintiff’s trademark claim; it applies in cases where the
defendant has engaged in some infringing use of its trademark—at least enough of
an infringing use so that it may attempt to avail itself of a laches or acquiescence
defense—but the plaintiff does not bring suit right away because the nature of
defendant’s infringement is such that the plaintiff’s claim has yet to ripen into one
sufficiently colorable to justify litigation.
Id. at 570. To apply the doctrine of progressive encroachment, something about the defendant’s
infringement must “have changed significantly,” such as an expansion of its marketing efforts or
entrance into new areas of business that more directly compete with the plaintiff. Nartron,
305 F.3d at 410.

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DayCab argues that it acted reasonably in waiting to file the suit until Defendants’
allegedly infringing products became prominent in the market, and that progressive
encroachment therefore excuses its delay. In support, DayCab points to the timeline on which its
awareness of Defendants’ allegedly infringing products developed. When Wagers first began
noticing Defendants’ allegedly infringing products in 2012, “they were few and far between” and
“did not initially make a significant impact on DayCab’s sales.” DayCab’s Resps. to Interrogs.,
R. 199-2, Page ID #3014. In 2015 or 2016, when Wagers and other DayCab personnel noticed
Defendants’ allegedly infringing products for sale on Defendants’ websites, Wagers “did not
consider that the sales of the offending products were making a significant impact on DayCab’s
sales.” Id. By 2018 or 2019, Wagers “began to see more and more of the offending products on
the highway” and “began to believe that the Defendants’ actions were generating sufficient
confusion and causing sufficient harm to justify litigation.” Id.
In his declaration, Wagers stated: “[a]s the years passed, I began to suspect that the
Prairie Technology/Big Truck Parts replicas were significantly cutting into DayCab’s sales and
becoming a significant drain on DayCab revenues and a significant threat to the company.”
Wagers Decl., R. 188, Page ID #2324. Beginning in 2017, Wagers stated that he “began seeing
more and more” of Defendants’ allegedly infringing products in the market and “became
concerned” because it indicated that Defendants were “more seriously encroaching on
[DayCab’s] business,” and that “[u]ntil that point, I did not consider Prairie Technology/Big
Truck Parts to be a significant problem that we should be worried about or that would be worth
pursuing a lawsuit.” Wagers’ Second Decl., R. 206-1, Page ID #3218-19. DayCab sent a cease-
and-desist letter to Defendants in March 2019, and when Defendants failed to respond, filed suit
in January 2020.
Defendants contest DayCab’s narrative, contending that there has been no significant
change in the appearance of Defendants’ allegedly infringing products since 2012, and no
significant change in their advertising or marketing since 2015 or 2016, that would support
excusing DayCab’s delay under a theory of progressive encroachment. However, as described
above, DayCab has presented evidence showing the increased presence of Defendants’ allegedly
infringing products in the market, which prompted DayCab to file suit when it did. Accordingly,

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it appears that the doctrine of progressive encroachment justifies DayCab’s delay in filing suit,
and that Defendants cannot establish the equitable defense of laches at the summary judgment
stage.
However, we acknowledge that factual disputes remain that bear on this analysis,
including the growing presence of Defendants’ allegedly infringing products in the market, the
effect of that growth on the likelihood of confusion between the products, and when the
infringement was of such significance as to ripen DayCab’s claim into one “sufficiently
colorable to justify litigation.” See Kellogg, 209 F.3d at 570. Although a court, rather than a
jury, will ultimately determine the applicability of laches to DayCab’s claim, as laches is an
equitable defense, that determination is not always appropriate at summary judgment, if the issue
implicates questions of fact appropriate for resolution at trial. See Innovation Ventures, LLC v.
Custom Nutrition Lab’ys, LLC, 912 F.3d 316, 344 (6th Cir. 2018) (affirming the district court’s
conclusion that disputes of material fact existed related to the issue of laches that precluded
summary judgment). Therefore, we refrain from deciding the issue of laches and remand it to
the district court to decide in the first instance following resolution of these factual disputes by
the jury.2
In any event, even if the laches issue is ultimately resolved in favor of Defendants, that
resolution will not fully resolve the merits of this action because laches “bars damages that
occurred before the filing date of the lawsuit” but does not prevent a plaintiff from obtaining
injunctive relief or post-filing damages. Nartron, 305 F.3d at 412.
2Although we recognize that laches is an equitable remedy, usually reserved to be decided by the court,
there is case authority indicating that it may be appropriate for the court to address laches only after certain factual
matters are litigated and resolved. See Innovation Ventures, 912 F.3d at 344; see also Mem’l Hall Museum, Inc. v.
Cunningham, 455 F. Supp. 3d 347, 360–361 (W.D. Ky. 2020) (holding that it was not appropriate to decide whether
laches applied at the summary judgment stage because material disputes of fact existed); Milcrofton Util. Dist. of
Williamson Cnty., Tennessee v. City of Brentwood, Tennessee, 458 F. Supp. 3d 757, 774 (M.D. Tenn. 2020) (holding
that questions of fact precluded summary judgment on the laches issue).

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CONCLUSION
For these reasons, we AFFIRM IN PART and REVERSE IN PART the district court’s
grant of summary judgment. Specifically, we REVERSE the grant of summary judgment to
Defendants on DayCab’s trade dress claim under the Lanham Act. We refrain from deciding
whether the doctrine of laches applies to DayCab’s claim and remand the laches issue to the
district court for determination in the first instance following resolution of factual disputes by a
jury. We AFFIRM the grant of summary judgment on DayCab’s state law claim on the
alternative basis that it is time barred. Finally, we AFFIRM the district court’s ruling on
DayCab’s motion to exclude the testimony of Defendants’ expert Dr. Wandling. We REMAND
this case for further proceedings consistent with this opinion.

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