This opinion is subject to revision before final 

publication in the Pacific Reporter 

2020 UT 59 

IN THE

SUPREME COURT OF THE STATE OF UTAH

NOE ARREGUIN-LEON, 

Petitioner, 

v. 

HADCO CONSTRUCTION, LLC, 

Respondent.

No. 20190121 

Heard February 10, 2020 

Filed August 17, 2020 

On Certiorari to the Utah Court of Appeals

Fourth District, Provo 

The Honorable Fred D. Howard 

No. 130400816 

Attorneys: 

Troy L. Booher, Beth E. Kennedy, Salt Lake City, Leonard McGee, 

Peter Mifflin, Sandy, for petitioner 

Robert L. Janicki, Michael L. Ford, Sandy, Harry Lee, 

Shannen W. Coffin, Mark C. Savignac, Washington D.C., 

for respondent 

JUSTICE PETERSEN authored the opinion of the Court, in which 

CHIEF JUSTICE DURRANT, ASSOCIATE CHIEF JUSTICE LEE, 

JUSTICE HIMONAS, and JUSTICE PEARCE joined. 

JUSTICE PETERSEN, opinion of the Court: 

INTRODUCTION 

Noe Arreguin1 ¶1 was injured while working on a highway 

construction site. He sued Hadco Construction, LLC, the general 

__________________________________________________________ 

1 Although the plaintiff’s last name in the case caption is 

Arreguin-Leon, we refer to him in this opinion as Arreguin 

because that is how he refers to himself in his briefing. 
ARREGUIN-LEON v. HADCO CONSTRUCTION, LLC 

Opinion of the Court

2 

contractor, for failing to take necessary safety measures to protect 

workers from highway traffic. Arreguin prevailed at trial. But 

during trial, he elicited undisclosed testimony from his expert 

witness. The court of appeals found this error to be harmful and 

reversed and remanded for a new trial. We affirm. 

BACKGROUND 

¶2 Noe Arreguin was injured while installing an exit sign on 

the shoulder of I-15. A driver fell asleep at the wheel and veered 

off the road and into the ladder on which Arreguin was standing. 

¶3 Arreguin worked for a company called Highway Striping 

& Signs. The company had been hired by Hadco to install signage 

for a Utah Department of Transportation roadway project in Utah 

County. In its role as general contractor, Hadco was responsible 

for implementing a “traffic control plan” composed of various 

safety measures to protect workers from traffic and drivers from 

the construction site. Hadco did not do so. At the time of the 

accident, there were no traffic control measures in place at the 

accident site, such as barrels or barriers. 

¶4 As a result of the accident, Arreguin sustained significant 

injuries. He sued the driver and Hadco (along with others who 

are not relevant to this appeal). 

¶5 Arreguin retained Bruce Reading as an expert witness on 

traffic control standards. Hadco’s counsel elected to depose 

Reading rather than receive an expert report. 

¶6 The case proceeded to a jury trial, at which Arreguin 

called Reading to testify. Reading opined that Hadco or its 

subcontractor had violated five specific engineering practices, 

regulatory standards, and contractual provisions and that there 

was no traffic control plan in place at the accident site. 

¶7 During direct examination, Arreguin’s counsel asked 

Reading, “If [200 yards from the construction project is] where 

[the driver] started to exit the roadway, what effect would a 

correctly installed buffer zone have had on his driving?” Hadco’s 

counsel objected and asked to approach the bench. The following 

sidebar ensued: 

[DEFENSE COUNSEL]: Seems to me like this 

testimony is going toward causation—would traffic 

control have prevented the accident—and it goes 

beyond any opinion that he’s ever disclosed in this 
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Opinion of the Court 

3 

case. There’s a list of his items of testimony, and he 

doesn’t touch on that at all. 

[PLAINTIFF COUNSEL]: Your Honor, Mr. Reading 

was deposed in this case. [Defense counsel] had 

every opportunity to ask any question he wanted, 

and—and he’s not limited to the initial disclosure. If 

he had—if [defense counsel] had elected a report, he 

would be limited to the contents of the report, but 

because a deposition has been elected, Mr. Reading 

is not so limited. 

[DEFENSE COUNSEL]: That’s not correct, your 

Honor. 

[PLAINTIFF COUNSEL]: And—and there were 

documents provided to Mr. Reading after 

(inaudible). 

[DEFENSE COUNSEL]: Then he needs to 

supplement his disclosure. 

THE COURT: Your objection is noted and is, 

frankly, overruled. 

[DEFENSE COUNSEL]: Can I make a record—a 

record on this? I think it’s very important. 

THE COURT: This record is the record here now. 

[DEFENSE COUNSEL]: Okay. Thank you. 

¶8 Reading then testified about the effect that a proper traffic 

control plan would have had, including that if the accident 

occurred where Hadco’s “safety person”2 suggested it did, it 

would have been within a 900-foot area where the driver would 

have hit “at least one, if not more, of th[e] plastic barrels” that 

would have been in place. He explained that after hitting at least 

one of the plastic barrels, the driver “would have had close to six 

seconds to wake up and take corrective action.” And he 

concluded that if traffic control had been in place, “[t]here might 

have been an accident still,” but it would not have taken place 

where it did. 

__________________________________________________________ 

2 At trial, Reading referred to Hadco’s “safety person.” From 

the context, we understand this person to be the Hadco employee 

who completed Hadco’s incident report about the accident. 
ARREGUIN-LEON v. HADCO CONSTRUCTION, LLC 

Opinion of the Court

4 

¶9 The trial continued and the jury ultimately found that 

Hadco was partially liable for Arreguin’s injury. The jury 

allocated 60 percent of the fault to the driver and 40 percent to 

Hadco. Hadco appealed. 

¶10 Approximately four months after filing its notice of 

appeal, Hadco filed Reading’s deposition transcript and 

Arreguin’s expert disclosures in the district court. They were 

included in the record that was certified to the court of appeals. 

¶11 One of Hadco’s arguments on appeal was that the district 

court erred under Utah Rule of Civil Procedure 26 when it 

allowed Reading to offer an undisclosed opinion on causation. 

Arreguin argued that Hadco could not prevail on this argument 

without relying on his expert disclosures and Reading’s 

deposition transcript. But he asserted it was improper for the 

court of appeals to consider these documents because they were 

not actually part of the trial record. 

¶12 The court of appeals decided to consider the disclosures 

and the deposition transcript. It “acknowledge[d] that [Reading’s] 

deposition was filed after the judgment was entered in this 

matter, but before the record was prepared” and that “such filings 

normally would not put the deposition before [the court of 

appeals] for consideration.“ Arreguin-Leon v. Hadco Constr. LLC, 

2018 UT App 225, ¶ 6 n.2, 438 P.3d 25. But it decided that “under 

the unique facts of this case” it would “exercise [its] discretion 

and consider the deposition.” Id.

¶13 The court of appeals concluded that the district court 

abused its discretion in allowing Reading to testify about 

causation at trial. Id. ¶ 20. And it determined that the error was 

“harmful enough to warrant reversal and a new trial.” Id. ¶ 32. 

¶14 Arreguin petitioned this court for certiorari, which we 

granted to address three questions: (1) “[w]hether the Court of 

Appeals erred in considering a deposition transcript that was not 

included in the record prior to the filing of the appeal”; 

(2) “[w]hether the Court of Appeals erred in construing [Hadco’s] 

arguments on appeal to present a sufficient basis for its conclusion 

that [Arreguin’s] expert testimony should have been excluded”; 

and (3) “[w]hether the Court of Appeals erred in its construction 

and application of the standard for demonstrating harmful error 

on appeal.” 

¶15 We have jurisdiction pursuant to Utah Code section 

78A-3-102(3)(a). 
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Opinion of the Court 

5 

STANDARD OF REVIEW 

¶16 “On certiorari, we review the court of appeals’ decision 

for correctness, without according any deference to its analysis.” 

Vander Veur v. Groove Entm’t Techs., 2019 UT 64, ¶ 7, 452 P.3d 1173 

(citation omitted) (internal quotation marks omitted). 

ANALYSIS 

I. CONSIDERATION OF ARREGUIN’S EXPERT DISCLOSURES 

AND THE EXPERT’S DEPOSITION TRANSCRIPT 

¶17 The first question before us is whether the court of 

appeals erred in considering Arreguin’s expert disclosures and 

Reading’s deposition transcript. Arreguin argues that the court of 

appeals should not have considered these documents because 

they were not truly part of the trial record, in that neither party 

submitted either document for the district court’s consideration at 

any point. Rather, Arreguin notes that Hadco filed the documents 

five months after the district court entered the final judgment in 

the case and four months after Hadco filed its notice of appeal. 

¶18 We take Arreguin’s point. When the district court ruled 

on Hadco’s objection, it did not actually have these documents 

before it. The court of appeals decided to consider this 

extra-record evidence because it determined Hadco’s counsel had 

attempted to make a further record during the sidebar but had 

been prevented from doing so by the district court. See

Arreguin-Leon v. Hadco Constr. LLC, 2018 UT App 225, ¶ 6 n.2, 438 

P.3d 25. The court of appeals analogized this situation to one in 

which a party is prevented from objecting, and thereafter should 

not be prejudiced by the lack of an objection. See id.; see also UTAH 

R. CIV. P. 46. Arreguin rejects this as a valid basis for considering 

the extra-record materials. 

¶19 We conclude that we do not need to resolve this dispute. 

We can affirm the court of appeals’ ruling on the disputed expert 

testimony without resort to the expert disclosures or deposition 

transcript. Arreguin’s premise is that the content of these 

documents is essential to Hadco’s argument—in other words, that 

Hadco cannot successfully argue that the district court erred in 

permitting Reading to testify about causation without relying on 

the content of (1) the expert disclosures to prove that Arreguin did 

not in fact disclose a causation opinion and (2) the deposition 

transcript to prove that Hadco had “locked in” Reading to only 

those opinions he offered during his deposition. But as we will 

discuss, Arreguin never put the content of these documents at 
ARREGUIN-LEON v. HADCO CONSTRUCTION, LLC 

Opinion of the Court

6 

issue in the district court. Arreguin essentially contends that 

Hadco must refute arguments he never made. 

¶20 The court of appeals did rely upon the documents in its 

reasoning, Arreguin-Leon, 2018 UT App 225, ¶ 23. But we disagree 

with the premise that they are necessary to Hadco’s argument or 

the court of appeals’ holding. As Hadco has argued, we can 

resolve the rule 26 issue based solely on the transcript of the 

sidebar between counsel and the district court at trial. 

¶21 Looking only at the sidebar, we agree with the court of 

appeals that the district court committed legal error in overruling 

Hadco’s objection. During the sidebar, Hadco argued that 

Arreguin’s question to Reading elicited a causation opinion, 

which went “beyond any opinion that [Arreguin had] ever 

disclosed in this case.” It is important to note Arreguin’s response. 

He did not dispute Hadco’s assertion that his question would 

elicit causation testimony. He did not assert that he had in fact 

disclosed that Reading would offer a causation opinion or that 

Reading had discussed causation in his deposition. And he did 

not argue that Hadco had failed to “lock in” Reading to only the 

opinions he had given at the deposition and therefore Reading 

was free to offer additional opinions. 

¶22 Instead, Arreguin asserted broadly that the expert was 

not limited at all because Hadco had opted for a deposition rather 

than an expert report. Arreguin’s counsel stated,

Your Honor, Mr. Reading was deposed in this case. 

[Defense counsel] had every opportunity to ask any 

question he wanted, and—and he’s not limited to 

the initial disclosure. If he had—if [defense counsel] 

had elected a report, he would be limited to the 

contents of the report, but because a deposition has been 

elected, Mr. Reading is not so limited. 

Hadco’s counsel responded, “That’s not correct, your Honor.” 

With these arguments before it, the court overruled Hadco’s 

objection and permitted the expert to offer the disputed 

testimony.3

__________________________________________________________ 

3 After this back-and-forth but before the court ruled, Arreguin 

interjected that Hadco had provided documents to Reading after 

the deposition. And Hadco countered, “[t]hen he needs to 

(continued . . .) 
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Opinion of the Court 

7 

¶23 As the court of appeals correctly concluded, the district 

court’s ruling was legally incorrect. Id. ¶ 26. Just because a party 

opponent selects a deposition rather than an expert report does 

not mean an expert’s subsequent trial testimony can be a 

“free-for-all.” Id. ¶ 21.

¶24 In general, rule 26 provides that “discovery may be 

obtained from an expert witness either by deposition or by 

written report.” UTAH R. CIV. P. 26(a)(4)(B). With respect to a 

written report, the rule makes clear that an expert is limited to 

opinions disclosed in the report. Id. (“A report shall . . . contain a 

complete statement of all opinions the expert will offer at trial and 

the basis and reasons for them. Such an expert may not testify in a 

party’s case-in-chief concerning any matter not fairly disclosed in 

the report.”). The rule itself does not make a similar statement 

with regard to an expert’s deposition. We generally agree with the 

relevant advisory committee note, which explains that “[i]f a 

party elects a deposition, rather than a report, it is up to the party 

to ask the necessary questions to ‘lock in’ the expert’s testimony.” 

Id. advisory committee note. In a case where an opposing party 

fails to “lock in” an expert witness during the deposition, the 

opposing party runs the risk of surprise testimony at trial. 

¶25 However, this does not equate to the blanket assertion 

advanced at trial by Arreguin that if Hadco “had elected a report, 

 

supplement his disclosure.” Hadco’s response was legally correct. 

See UTAH R. CIV. P. 26(d)(3)–(4); see also Arreguin-Leon v. Hadco 

Constr. LLC, 2018 UT App 225, ¶ 23, 438 P.3d 25. And we do not 

think that this additional exchange requires a review of the 

content of the disclosures. Here too, Arreguin did not respond 

that he had supplemented his disclosures or otherwise provided a 

causation opinion at some point before trial. So he did not put the 

content of his disclosures at issue. 

Arreguin asserts in his briefing to us that Hadco forfeited its 

argument that Arreguin failed to supplement his disclosures. 

Arreguin argues that although Hadco preserved this argument 

during the sidebar, it did not raise the same argument in its 

briefing to the court of appeals, so the argument has been waived. 

However, Hadco has consistently asserted that Arreguin never 

disclosed or produced, in any form or at any time before trial, a 

causation opinion from Reading. Accordingly, we reject 

Arreguin’s preservation argument. 
ARREGUIN-LEON v. HADCO CONSTRUCTION, LLC 

Opinion of the Court

8 

[Reading] would be limited to the contents of the report, but 

because a deposition has been elected, Mr. Reading is not so 

limited.” Arreguin’s counsel did not put the contents of the 

disclosures or deposition at issue by asserting that a causation 

opinion had in fact been disclosed at some point or that Hadco 

had not properly “locked in” Reading at his deposition and 

therefore he was free to offer new opinions at trial. Rather, 

Arreguin made a very broad assertion to the district court that if a 

party opponent elects to depose an expert witness, then the expert 

witness is not limited during trial testimony. This is an incorrect 

interpretation of rule 26(a)(4)(B), which the district court should 

have rejected. 

¶26 Accordingly, we agree with the court of appeals that the 

district court should not have permitted Reading to offer the 

disputed testimony based on the arguments before it. See id.

26(d)(4) (“If a party fails to disclose or to supplement timely a 

disclosure or response to discovery, that party may not use the 

undisclosed witness, document or material at any hearing or trial 

unless the failure is harmless or the party shows good cause for 

the failure.”). And we conclude that although the court of appeals 

reviewed the disclosures and deposition and determined that 

Arreguin had not disclosed a causation opinion and that Hadco 

did in fact “lock in” Reading to the opinions he provided at the 

deposition, this was not necessary to reach the correct legal result 

because Arreguin had never argued otherwise.4

II. UTAH RULE OF APPELLATE PROCEDURE 11 

¶27 Although we do not need to reach the issue of whether 

the court of appeals erred in considering the deposition transcript, 

the parties’ briefing and oral argument did elucidate certain 

ambiguities in Utah Rule of Appellate Procedure 11 that we flag 

for our appellate rules advisory committee. The relevant portions 

of rule 11 state, 

(a) Composition of the record on appeal. The 

original papers and exhibits filed in the trial court, 

__________________________________________________________ 

4 Arreguin also argues in his briefing to us that “because 

Hadco did not make the documents part of the record, Hadco 

could not show prejudice on appeal.” We are unsure how to 

interpret this argument, and we are unable to resolve it because 

Arreguin does not explain the argument further. 
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Opinion of the Court 

9 

. . . the transcript of proceedings, if any, the index 

prepared by the clerk of the trial court, and the 

docket sheet, shall constitute the record on appeal in 

all cases. . . . Only those papers prescribed under 

paragraph (d) of this rule shall be transmitted to the 

appellate court. 

. . . 

(d)(2) Civil cases. Unless otherwise directed by the 

appellate court upon sua sponte motion or motion of 

a party, the clerk of the trial court shall include all of 

the papers in a civil case as part of the record on 

appeal. 

. . . 

(h) Correction or modification of the record. If any 

difference arises as to whether the record truly 

discloses what occurred in the trial court, the 

difference shall be submitted to and settled by that 

court and the record made to conform to the truth. If 

anything material to either party is misstated or is 

omitted from the record by error, by accident, or 

because the appellant did not order a transcript of 

proceedings that the appellee needs to respond to 

issues raised in the Brief of Appellant, the parties by 

stipulation, the trial court, or the appellate court, 

either before or after the record is transmitted, may 

direct that the omission or misstatement be 

corrected and, if necessary, that a supplemental 

record be certified and transmitted. 

UTAH R. APP. P. 11. 

¶28 First, rule 11 references “the record” throughout, but it 

does not define it. Rule 11(a) states that the “original papers and 

exhibits filed in the trial court, . . . the transcript of proceedings, if 

any, the index prepared by the clerk of the trial court, and the 

docket sheet, shall constitute the record on appeal in all cases.” Id.

11(a) (emphasis added). It goes on to say that “only those papers 

prescribed under paragraph (d) . . . shall be transmitted to the 

appellate court.” Id. Rule 11(d)(2), which relates specifically to 

civil cases, is quite broad. It states that the clerk “shall include all 

of the papers in a civil case as part of the record.” Id. 11(d)(2). But 

as illuminated here, there is ambiguity as to what “all of the 

papers in a civil case” includes. Arreguin asserts that the record 
ARREGUIN-LEON v. HADCO CONSTRUCTION, LLC 

Opinion of the Court

10 

should include only those items that were actually presented in 

court in some manner. However, the rule does not make explicit 

that this is the case. 

¶29 Next, rule 11(h) provides a mechanism for parties to 

correct or modify the record. It states that, “[i]f any difference 

arises as to whether the record truly discloses what occurred in 

the trial court, the difference shall be submitted to and settled by 

that court and the record made to conform to the truth.” Id. 11(h). 

This has a clear meaning in some contexts—for example, if a 

transcript inaccurately documents a witness’s testimony and can 

be corrected by comparing the transcript to the audio recording of 

the testimony, that would seem to make the record conform to the 

truth. But in other contexts, the scope of what is meant by making 

the record “conform to the truth” may not be entirely clear. 

¶30 Finally, rule (11)(h) also permits modification of the 

record “[i]f anything material to either party is misstated or is 

omitted from the record by error” or “by accident.” But the rule 

does not define either of these terms, and the scope of what might 

be encompassed within them is not entirely clear.5

III. HARMLESS ERROR 

¶31 Next, we must determine whether the court of appeals 

erred in its construction and application of the standard for 

demonstrating harmful error on appeal. We conclude it did not. 

__________________________________________________________ 

5 We also flag for our civil rules advisory committee a concern 

raised by Arreguin’s counsel at oral argument regarding the court 

of appeals’ treatment of Utah Rule of Civil Procedure 50(b). By 

way of background, Arreguin argued in the court of appeals that 

Hadco’s claims on appeal were unpreserved because Hadco had 

not renewed its motion for directed verdict after trial, and 

therefore had failed to meet the procedural requirements of rule 

50(b). The court of appeals ultimately did not need to resolve this 

argument but briefly addressed it in a footnote. See Arreguin-Leon 

v. Hadco Constr. LLC, 2018 UT App 225, ¶ 29 n.9, 438 P.3d 25. At 

oral argument before this court, counsel for Arreguin raised a 

concern with this footnote. Because this issue is not before us, we 

do not address it or opine one way or the other on the court of 

appeals’ take on the rule. But we refer counsel’s concern to our 

civil rules advisory committee for consideration. 
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Opinion of the Court 

11 

¶32 Arreguin argues that the court of appeals misapplied the 

harmlessness standard, citing to the court of appeals’ statement 

that it could not conclude “that the jury would have inevitably 

reached the same result without Expert’s testimony.” 

Arreguin-Leon v. Hadco Constr. LLC, 2018 UT App 225, ¶ 28, 438 

P.3d 25. He contends that this is the incorrect standard. 

¶33 Arreguin is correct that the cited sentence is not the 

correct harmlessness standard. Rather, “[h]armless error is an 

error that is sufficiently inconsequential that there is no 

reasonable likelihood that it affected the outcome of the 

proceedings.” H.U.F. v. W.P.W., 2009 UT 10, ¶ 44, 203 P.3d 943 

(citation omitted). However, although the court of appeals used 

the language Arreguin identifies, it does not appear to us that it 

mistakenly thought this was the applicable legal standard. In the 

preceding paragraph, the court of appeals correctly stated that 

“[a]n error is harmful ‘only if the likelihood of a different outcome 

is sufficiently high as to undermine our confidence in the 

verdict.’” Arreguin-Leon, 2018 UT App 225, ¶ 27 (citation omitted). 

This is substantively similar to the legal standard we identify 

above. When the court used the disputed language, we agree with 

Hadco that it was merely a shorthand reference to the legal 

standard it had already identified. We see no legal error in the 

court of appeals’ application of the law. 

¶34 Arreguin also argues that the court of appeals erred when 

it found the district court’s error to be harmful. He argues that 

“expert testimony is not required to establish [the] obvious 

proposition” that “if Hadco had set out the barrels to block traffic, 

the driver would have hit at least one of them, woken up, and 

taken corrective action” and “the barrels with sand in the bottom 

likely would have prevented the driver from crashing into 

[Arreguin].” Accordingly, he asserts that any error was harmless 

because Reading’s testimony was “unnecessary and cumulative of 

common sense” and “stated the obvious.” 

¶35 We are not convinced. After the district court overruled 

Hadco’s objection, Reading went beyond his testimony about the 

components of a proper traffic safety plan and gave his opinion of 

how such a safety plan would have changed the events that led to 

Arreguin’s injury. Reading testified that if the driver drifted off 

the road 200 yards back, he would have hit a barrel and “would 

have been aware immediately upon impact” of the barrel. He 

estimated that based on a two-and-a-half second reaction time, the 

driver would have had “six seconds to wake up and take 
ARREGUIN-LEON v. HADCO CONSTRUCTION, LLC 

Opinion of the Court

12 

corrective action.” He then would have “jerk[ed] hard left.” 

Ultimately, Reading opined that “[t]here might have been an 

accident still. There’s no question about that. I don't think the 

accident would have taken place where this happened.” 

¶36 We think this testimony goes beyond common sense. A 

lay juror could be expected to understand the gist of Reading’s 

causation opinion—that the sleeping driver might hit a barrel, 

wake up, and attempt a correction. But a layperson would not 

necessarily understand with such precision the effect of a traffic 

safety plan upon the events in question. And even if a layperson 

might have assumed that “the accident would [not] have taken 

place where this happened,” this opinion carried extra weight 

because it came from an expert. We agree with the court of 

appeals’ observation that Reading’s testimony “carried the 

imprimatur of coming from an ‘expert,’” and it “provided a 

logical roadmap that the jury could—and likely did—follow in 

deciding the issues of liability and in apportioning fault.” Id. ¶ 28. 

¶37 Arreguin also argues that the error was harmless because 

Reading’s testimony was cumulative of testimony given by other 

witnesses. But we do not view the testimony from the other 

witnesses to be equivalent to Reading’s causation testimony. 

¶38 Arreguin argues that Reading’s testimony that the 

sleeping driver would have hit a barrel was duplicative of 

testimony from Hadco’s expert. But this is not so clear. Reading 

testified that given the parameters suggested by Hadco’s “safety 

person,” the driver “would have [hit][6] at least one, if not more, of 

these plastic barrels.” In comparison, Hadco’s expert testified 

about calculating tapers and spacing of traffic control devices, but 

he did not say that the sleeping driver would have hit a barrel. 

The closest Hadco’s expert came to saying this was noting that a 

traffic control device is an “indicator” and that barrels are “not 

going to stop a vehicle from departing the roadway,” while 

agreeing that they would “notify.” Reading’s testimony was more 

specific and certain, and it was not cumulative of the testimony 

from Hadco’s expert. 

__________________________________________________________ 

6 The transcript says this word was inaudible. From the context 

of the sentence, it appears that the word was “hit” or another 

synonymous word. 
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Opinion of the Court 

13 

¶39 Arreguin also argues that Reading’s testimony that 

hitting the barrel would have awakened the driver was 

cumulative of testimony from Hadco’s expert, Hadco’s project 

manager, and the driver. Reading opined that hitting a barrel 

would lead to a “hellacious sound” that is “going to wake him 

up.” In contrast, when asked “if striking a barrel can be a jolting, 

noisy experience,” Hadco’s expert responded, “Well, yes.” He 

then commented, “I can’t say, if someone is already asleep, 

though, if that would be something that would necessarily wake 

them up.” When asked, “Would you agree that it is possible that 

there was a barrel on the side of the road and [the driver] hit it as 

he was going off the road, that it may have alerted him,” Hadco’s 

expert responded, “It could have. I mean, I—I would be 

speculating, but yeah. I couldn’t say specifically that it would, but 

it may have.” Hadco’s project manager agreed that barrels need to 

be “crashworthy.” And the driver testified that he woke up when 

he heard “the grids in the road.” Arreguin argues that based on 

this testimony, the jury could infer that if a rumble strip 

awakened the driver, hitting a barrel also would have awakened 

him. While that might be a fair inference, we disagree with 

Arreguin’s assertion that Reading’s testimony is merely 

duplicative of the other witnesses’ testimony. Again, Reading’s 

testimony was specific and certain, while the testimony of the 

other witnesses was equivocal or required an inferential leap. 

¶40 Arreguin next argues that Reading’s testimony that the 

driver would have taken corrective action also came from Hadco’s 

expert and the driver. Again, Hadco’s expert testified about 

calculating tapers and spacing of traffic control devices. He did 

not clearly state that the driver would have taken corrective 

action. Similarly, the driver testified that upon waking up and 

seeing a flatbed truck in front of him he “swerved off to the side 

to avoid it.” Neither is equivalent to Reading’s testimony that the 

driver “would have had close to six seconds to wake up and take 

corrective action,” that “the normal experience is you jerk hard 

left to get back on,” and finally that “[t]here might have been an 

accident still,” but he did not “think the accident would have 

taken place where this happened.” 

¶41 Reading’s disputed testimony related to the important 

questions of whether and to what extent Hadco’s failure to 

implement a proper traffic control plan on the day of the accident 

caused Arreguin’s injuries. While other witnesses made 

statements from which the jury could possibly have inferred the 

disputed facts and opinions Reading provided, none of them gave 
ARREGUIN-LEON v. HADCO CONSTRUCTION, LLC 

Opinion of the Court

14 

testimony that was equivalent to Reading’s. None of the other 

witnesses’ testimony on the disputed points was as clear, specific, 

and emphatic as Reading’s. We agree with the court of appeals 

that the district court’s error was not harmless. The erroneously 

admitted testimony was not “sufficiently inconsequential that 

there is no reasonable likelihood that it affected the outcome of 

the proceedings.” See H.U.F., 2009 UT 10, ¶ 44 (citation omitted). 

CONCLUSION 

¶42 We agree with the court of appeals that the district court 

abused its discretion in allowing Reading to offer causation 

testimony. This error was harmful. We affirm the court of appeals’ 

decision, and we remand to the district court for a new trial.