State v. Montgomery

2026 UT App 77

THE UTAH COURT OF APPEALS

STATE OF UTAH,
Appellee,
v.
NATHAN MONTGOMERY,
Appellant.

Opinion
No. 20241296-CA
Filed May 14, 2026

Third District Court, Salt Lake Department
The Honorable James Blanch
No. 245900218

Dain Smoland, Attorney for Appellant
Simarjit S. Gill and Marc Douglas Fiaui,
Attorneys for Appellee

JUDGE GREGORY K. ORME authored this Opinion, in which
JUDGES RYAN M. HARRIS and RYAN D. TENNEY concurred.

ORME, Judge:

¶1 Nathan Montgomery appeals the district court’s denial of
his motion in limine to exclude the results of his breath alcohol
test. Among other things, he argues that the test results were
unreliable because the officer who administered the test (Officer)
failed to first check Montgomery’s mouth for anything that might
affect the results. We agree that mouth checks are critical to
ensuring the reliability of breath alcohol test results. Accordingly,
we reverse the denial of Montgomery’s motion in limine and
remand the matter to the district court for further proceedings.
State v. Montgomery

BACKGROUND

¶2 The State charged Montgomery with one count of driving
under the influence of alcohol for the second time in ten years (the
DUI charge), a class A misdemeanor, and one count of failure to
observe a barricade, a class B misdemeanor. According to the
probable cause statement, Officer initiated a stop on
Montgomery’s car after he observed Montgomery drive around a
police barricade on a highway. Upon approaching the vehicle,
Officer “detected a strong odor of alcohol” and he observed that
Montgomery’s “eyes were blood-shot” and that “he was slurring
his words.” A field sobriety test, which Montgomery began but
refused to complete, also showed signs of impairment.

¶3 Officer took Montogomery to the police station where,
after some discussion, Mongomery agreed to submit to a breath
alcohol test. Following an observation period of over 30 minutes,
Officer administered the test. Officer’s body camera, which
Officer placed on the table facing Montgomery, recorded the
entirety of the observation period and the administration of the
test. Montgomery’s breath alcohol level was measured at 0.21—
well above the 0.05 legal threshold.

¶4 After being bound over for trial, Montgomery filed a
motion in limine to exclude the results of the breath alcohol test
on the rationale advanced in State v. Baker, 355 P.2d 806 (Wash.
1960) (en banc) (the Baker motion). 1 He argued that the test results
were unreliable because (1) Officer did not check his mouth at the
beginning of the required observation period immediately

1. Montgomery also filed a motion to suppress the test results on
the ground that his consent to the test was coerced, which the
district court also denied. Because we do not reach this issue on
appeal, see infra note 2, we do not recount the facts relevant to that
issue.

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State v. Montgomery

preceding the test and (2) Officer did not properly observe him
during the observation period.

¶5 Because Officer failed to appear at the first scheduled
evidentiary hearing on the Baker motion, the district court
continued the hearing until the following week. But after Officer
was again unavailable to appear in person at the continued
hearing, and after Montgomery objected to Officer appearing
virtually, the State stipulated, for purposes of the Baker motion,
that Officer “did not check Mr. Montgomery’s mouth and left the
room during the observation period.” But in its later written
opposition to the Baker motion, the State apparently disregarded
the latter portion of its stipulation. Instead, citing footage from
Officer’s body camera, which the State also stipulated to the court
watching “off calendar,” the State asserted that Officer never
exited the room during the entirety of the observation period.

¶6 At a subsequent hearing, after discussing relevant caselaw,
the district court concluded that although a mouth check was not
strictly “required,” “the absence of a mouth check, depending on
the facts and circumstances, could prevent the State from showing
by a preponderance of the evidence that there wasn’t something
in the mouth during the observation period.” The court noted that
although “there was not strictly speaking a mouth check in the
sense that [Officer] . . . took a flashlight and looked in Mr.
Montgomery’s mouth,” “the entirety of the observation period
was captured on” “over 30 minutes” of “high quality” video with
“very good” audio. And the court ultimately ruled that based on
the “speech and the interaction” between Officer and
Montgomery throughout the observation period, there was
“other evidence to conclude that [Montgomery’s] mouth was
clear during the Baker observation period.”

¶7 As for Montgomery’s argument that Officer did not
properly observe him, the court agreed with the State’s written
opposition, noting that “[t]he door in and out of the room is

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State v. Montgomery

visible in the video” and “[i]t didn’t look like [Officer] left the
room.” The court further stated that even assuming, for the sake
of argument, that Officer did not properly observe Montgomery,
the court nevertheless remained confident “in the validity of the
observation period” because the entirety of the observation
period “was captured on . . . high quality audio and video.”
Accordingly, the court denied the Baker motion.

¶8 Montgomery subsequently entered a conditional plea of no
contest to the DUI charge, reserving his right to appeal the denial
of the Baker motion. See Utah R. Crim. P. 11(j); State v. Sery, 758
P.2d 935, 937–39 (Utah Ct. App. 1988). The failure to observe a
barricade charge was dismissed.

ISSUE AND STANDARDS OF REVIEW

¶9 On appeal, Montgomery challenges the denial of the Baker
motion that sought to exclude the results of the breath alcohol test
based on Officer’s failure to perform an initial mouth check. 2
Generally, we review “a district court’s decision to admit or
exclude evidence” for an “abuse of discretion.” State v. Green, 2023
UT 10, ¶ 43, 532 P.3d 930 (quotation simplified). See State v.
Vialpando, 2004 UT App 95, ¶ 13, 89 P.3d 209 (“A trial court’s
determination that there was a proper foundation for the

2. Montgomery also argues that the district court erred in denying
the Baker motion because it “substituted its own ‘presence’ and its
own ‘powers of observation’ for [Officer’s] to reach the ultimate
conclusion that ‘Mr. Montgomery’s mouth was clear’ during the
observation period.” He further challenges the court’s denial of
his motion to suppress the test results on coercion grounds, see
supra note 1, which issue he also reserved the right to appeal in
the conditional plea agreement. But because we conclude that the
results of the breath alcohol test were inadmissible due to
Officer’s failure to perform a mouth check and reverse on that
ground, we have no need to address these other issues.

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State v. Montgomery

admission of evidence will not be overturned unless there is a
showing of an abuse of discretion.”) (quotation simplified). But
because district courts “do not have discretion to misapply the
law,” State v. De La Rosa, 2019 UT App 110, ¶ 4, 445 P.3d 955
(quotation simplified), “whether the district court applied the
proper legal standard in assessing the admissibility of evidence is
a question of law that we review for correctness,” Green, 2023 UT
10, ¶ 43 (quotation simplified).

ANALYSIS

¶10 In challenging the denial of the Baker motion, Montgomery
argues that the district court committed legal error when it
concluded that the results of his breath alcohol test were reliable
despite the lack of a mouth check. We agree and hold that a mouth
check is a foundational requirement for the admissibility of breath
alcohol tests.

¶11 In Utah, the admissibility of a breath alcohol test result is
contingent on the satisfaction of three foundational requirements
originally derived from State v. Baker, 355 P.2d 806 (Wash. 1960)
(en banc). See State v. Relyea, 2012 UT App 55, ¶ 29, 288 P.3d 278.
To establish the reliability of breath alcohol test results, the State
must show that

(1) the . . . machine had been properly checked by a
trained technician, and that the machine was in
proper working condition at the time of the test;
(2) the test was administered correctly by a qualified
operator; and (3) a police officer observed the
defendant during the fifteen minutes immediately
preceding the test to ensure that the defendant
introduced nothing into his or her mouth during
that time.

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State v. Montgomery

State v. Vialpando, 2004 UT App 95, ¶ 14, 89 P.3d 209. See Baker, 355
P.2d at 809–10. At issue here is the third requirement. 3

¶12 Under Baker, an officer is required to ensure “that the
subject had nothing in his mouth at the time of the test and that
he had taken no food or drink within fifteen minutes prior to
taking the test.” 355 P.2d at 810. The purpose of the 15-minute
observation period is to allow any residual alcohol in the mouth
to be absorbed into the system and to prevent the introduction of
foreign matter into the mouth that could taint the results, either
through ingestion or regurgitation. See id. at 811; Vialpando, 2004
UT App 95, ¶¶ 14, 18.

3. Pursuant to statutory directive to “establish standards for the
administration and interpretation of chemical analysis of a
person’s breath or oral fluids, including standards of training,”
Utah Code Ann. § 41-6a-515(1) (LexisNexis 2024), the
commissioner of the Department of Public Safety has adopted a
regulatory framework for breath alcohol testing in Utah, see Utah
Admin. Code R714-500-1 to -13. See also Utah Code Ann.
§ 41-6a-515(3) (stating that when the commissioner’s standards
and other conditions are satisfied, the test results carry a
presumption of validity and no further foundation is required).
Those administrative rules specifically address the first two
foundational requirements stated in State v. Vialpando, 2004 UT
App 95, ¶ 14, 89 P.3d 209, providing extensive directives for the
certification of the instruments and the certification and training
of operators and technicians. See Utah Admin. Code
R714-500-6, -8, -9. But the rules are largely silent on the process of
administering such tests, see Utah Code Ann. § 41-6a-515(1)
(directing the adoption of standards “for the administration” of
breath alcohol tests), which process encompasses the third
foundational requirement stated in Vialpando. As discussed
below, in Utah this third requirement has been developed
through caselaw.

20241296-CA 6 2026 UT App 77
State v. Montgomery

¶13 The legal standards governing the observation period have
been developed in two key Utah cases: Vialpando and Relyea. First,
in Vialpando, after the defendant failed a series of field sobriety
tests, the arresting officer drove the defendant, who was seated in
the front seat next to the officer, back to the police station to
perform a breath alcohol test. 2004 UT App 95, ¶ 4. During the
drive, the officer pulled over to allow the defendant to vomit,
following which the officer checked the defendant’s mouth with
a flashlight “to ensure that it was clear of foreign matter.” Id.
¶¶ 15–16. At the station, during the observation period, the officer
prepared the testing machine and administered the test after 15
minutes had passed. Id. ¶¶ 5, 16. On appeal, the defendant
assailed the quality of the officer’s observation. Id. ¶ 18. This court
held that an officer is not required to give the suspect his
“undivided attention” during the observation period. Id. Rather,
the observation requirement is satisfied if three criteria are met:
(1) the suspect remains “in the officer’s presence for the entire
period,” (2) the suspect has “no opportunity to ingest or
regurgitate anything” during that time, and (3) the officer’s ability
to observe remains unimpeded throughout the period. Id. And
this court concluded that the circumstances of that case, which
included a mouth check, supported “a reasonable belief that [the
defendant’s] mouth was clear for the entire observation period.”
Id. ¶ 19.

¶14 Next, in Relyea, this court clarified that an initial mouth
check “ensures that a suspect’s mouth is clear of foreign objects
prior to the test.” 2012 UT App 55, ¶ 31. In that case, the arresting
officer performed a mouth check on the defendant. Id. ¶ 4. After
instructing the defendant to spit out some chewing tobacco, the
officer rechecked his mouth, ensuring it was empty. Id. But during
the five-minute drive to the police station, the officer was unable
to properly observe the defendant, who was seated in the back
seat of the patrol car. Id. The officer acknowledged he would not
have known if the defendant had belched or regurgitated
anything during that time. Id. After arriving at the station, the

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State v. Montgomery

officer observed the defendant for 16 minutes before
administering the breath alcohol test. Id. On appeal, the defendant
challenged the admissibility of the test results, arguing that the
officer failed to perform a recheck of his mouth after arriving at
the station. Id. ¶ 30 & n.7. This court rejected that argument,
holding that “if after an initial check of the mouth, the officer’s
continuous observation of the suspect is interrupted, a recheck is
not required where the suspect had no opportunity to ingest or
regurgitate anything during the period of interrupted
observation.”4 Id. ¶ 31 (emphasis added). After concluding that
this standard was satisfied and a recheck of the mouth was not
required in that case, id. ¶ 32, this court next addressed whether
the three criteria for observation periods were satisfied during the
16-minute observation period at the station, id. ¶ 33, ultimately
concluding that they had been satisfied, id. ¶ 38.

¶15 When viewed together, Vialpando and Relyea establish that
an initial mouth check is required to satisfy the third foundational
requirement for admissibility of breath alcohol test results. See
Vialpando, 2004 UT App 95, ¶ 14; supra ¶ 11. Indeed, all three
criteria for the 15-minute observation requirement, see Vialpando,
2004 UT App 95, ¶ 18; supra ¶ 13, are necessarily undermined if
the officer fails to establish that the suspect’s mouth is empty to
begin with. Further, Baker’s Washington progeny has likewise
expressly required an initial mouth check, concluding that both
the mouth check and observation period are “integral steps” in

4. The defendant later testified at an evidentiary hearing that
while in the back seat, a flare up of a medical condition caused
him to regurgitate, but only into “the back of his throat.” State v.
Relyea, 2012 UT App 55, ¶¶ 6, 32, 36, 288 P.3d 278 (quotation
simplified). Given, among other things, the defendant’s
acknowledgement “that he quickly swallowed down any residue
from the regurgitation” such that it did not reach his mouth, this
court held that “a subsequent check of [his] mouth after arriving
at the police station was unnecessary.” Id. ¶¶ 32, 36.

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ensuring the reliability of breath alcohol tests. See State v. Trevino,
903 P.2d 447, 453–54 (Wash. 1995). 5

¶16 For these reasons, a mouth check is an essential step in
ensuring that a suspect’s mouth is clear of anything that might
taint the results of a breath alcohol test.6 The district court
therefore erred in denying the Baker motion.

CONCLUSION

¶17 Because Officer failed to perform a mouth check prior to
the observation period, the district court erred as a matter of law
when it denied the Baker motion seeking to exclude the results of
Montgomery’s breath alcohol test. Accordingly, we reverse
Montgomery’s conviction on the DUI charge and remand the
matter for further proceedings consistent with this opinion.

5. We note that in reaching this conclusion, the Trevino court cited
an administrative rule that Washington State had adopted since
Baker. See State v. Trevino, 903 P.2d 447, 454 (Wash. 1995) (citing
Wash. Admin. Code § 448-13-040). As discussed in note 3 above,
Utah’s administrative rules are largely silent on the process of
administering breath alcohol tests.

6. We recognize that when our Supreme Court first adopted the
general 15-minute observation period from Baker, it affirmed a
DUI conviction where the defendant had been continuously
observed for 45 minutes by the officer who administered the
breathalyzer test—three times the amount Baker requires—and
adjudged that observation period “clearly adequate to render the
breathalyzer result reliable,” without any mention of a physical
check of the defendant’s mouth. Salt Lake City v. Womack, 747 P.2d
1039, 1041 (Utah 1987). But it was not until the decisions in
Vialpando and Relyea that the precise legal contours of the
observation period were articulated and developed.

20241296-CA 9 2026 UT App 77