Supreme Court of California Justia
Docket No. S213545
Coffey v. Shiomoto

Filed 4/6/15


Plaintiff and Appellant,
Ct.App. 4/3 G047562
JEAN SHIOMOTO, as Director, etc.,
Orange County
Defendant and Respondent.
) Super. Ct. No. 30-2012-00549559

A California Highway Patrol officer stopped a car driven by plaintiff
Ashley Jourdan Coffey after he observed her driving erratically. Four subsequent
chemical tests revealed her blood-alcohol concentration (BAC) ranged from 0.08
to 0.096 percent. The officer then confiscated plaintiff‘s driver‘s license and
served her with a notice that her license would be suspended pursuant to Vehicle
Code section 13382.1 In an administrative hearing to review the suspension,
plaintiff‘s expert witness opined that her BAC was rising at the time of the
chemical tests, suggesting her BAC was below the 0.08 percent threshold at the
time plaintiff was driving. Both the Department of Motor Vehicles (DMV)
hearing officer and the trial court discounted the expert‘s testimony in part by
relying on arrest reports, which described the physical manifestations of plaintiff‘s

All statutory references are to the Vehicle Code unless otherwise stated.

intoxication, such as her general appearance, erratic driving, poor performance on
field sobriety tests, and the strong odor of alcohol she projected.
We decide in this case whether the trial court erred by considering, in
addition to the results of breath and blood tests, other circumstantial evidence of
intoxication to conclude by a preponderance of the evidence that plaintiff drove
with a BAC at or above 0.08 percent. As we explain, we conclude the trial court
did not err.
On November 13, 2011, at 1:32 in the morning, Sergeant Martin of the
California Highway Patrol was traveling southbound on State Route 55 in Orange
County when he saw a car traveling 60 miles per hour, swerving erratically from
side to side. From the number four, or right-hand, lane, the car swerved one foot
to the left into the number three lane before correcting. It then twice swerved one
to two feet to the right, onto the highway‘s shoulder. Sergeant Martin positioned
his patrol vehicle behind the car and activated his emergency lights, whereupon
the car slowly moved left across the highway into the number one lane. When
Martin activated his siren, the car veered even further left, into the carpool lane.
Only when Sergeant Martin used his public address system and directed the driver
to pull to the right did the car eventually comply.
Upon making contact with the driver of the vehicle, plaintiff Ashley
Coffey, Sergeant Martin noticed her eyes were red and a strong odor of alcohol
emanated from her car. Officer White arrived to provide backup and confirmed
these observations. To both officers she denied having consumed any alcoholic
beverages, offering the rather implausible story that she had just turned 21 years
old, had been in a bar, but had not herself consumed any alcoholic beverages. The
officers then had plaintiff perform various field sobriety tests. Plaintiff failed the
horizontal gaze nystagmus test, ―display[ing] a lack of smooth pursuit in both

eyes.‖2 Asked to complete the ―walk-and-turn test,‖ in which she was asked to
walk heel to toe for nine steps, turn counterclockwise, and then walk back heel to
toe, ―she missed heel to toe on five of those nine steps by 2–4 inches on each step.
When she reached step nine, . . . she turned clockwise instead of counter clockwise
as instructed. . . . [She] used both feet to make the turn instead of keeping her
front foot in place‖ and on the return similarly ―missed heel to toe three of the
steps by 2–4 inches.‖3

― ‗Nystagmus is an involuntary rapid movement of the eyeball, which may
be horizontal, vertical, or rotary. [Citation.] An inability of the eyes to maintain
visual fixation as they are turned from side to side (in other words, jerking or
bouncing) is known as horizontal gaze nystagmus, or HGN. [Citation.] Some
investigators believe alcohol intoxication increases the frequency and amplitude of
HGN and causes HGN to occur at a smaller angle of deviation from the forward
direction.‘ ‖ (People v. Leahy (1994) 8 Cal.4th 587, 592.)

The ― ‗walk-and-turn test‘ ‖ is significant because it tests ― ‗many of the
same skills needed for driving,‘ such as small muscle control, information
processing, reaction, balance, coordination, and short-term memory.‖ (U.S. v.
(9th Cir. 2007) 501 F.3d 1093, 1100.)

―Officers administering the Walk-and-Turn test observe the suspect‘s
performance for eight clues:

―• can‘t balance during instructions;
―• starts too soon;
―• stops while walking;
―• doesn‘t touch heel-to-toe;
―• steps off line;
―• uses arms to balance;
―• loses balance on turn or turns incorrectly; and,
―• takes the wrong number of steps.‖
(Utah Prosecution Council, Driving Under the Influence Prosecution Manual
(2007) ch. 8, p. 8 <
ProsecutionManual/chapter 8.pdf> [as of April 6, 2015] (Utah Prosecution
Manual).) ―Original research shows that if a suspect exhibits two or more of the
clues, or cannot complete the test, the suspect‘s BAC is likely to be above 0.10
[percent]. This criterion has been shown to be accurate 68 percent of the time.‖

Plaintiff did somewhat better on the ―one-leg stand‖ test,4 standing on one
foot and counting out loud beginning with 1,001; the test was terminated when she
reached 1,022 after 30 seconds. On the Romberg test,5 ―[s]he swayed slightly in

In the ―one-leg stand‖ test, after listening to the instructions, ―the subject
must raise one leg, either leg, with the foot approximately six inches off the
ground, keeping raised foot parallel to the ground. While looking at the elevated
foot, count out loud in the following manner:

― ‗[O]ne thousand and one‘, ‗one thousand and two‘, ‗one thousand and
three‘ until told to stop. This divides the subject‘s attention between balancing
(standing on one foot) and small muscle control (counting out loud).

―The timing for a thirty-second period by the officer is an important part of
the One-Leg Stand test. The original research has shown that many impaired
subjects are able to stand on one leg for up to 25 seconds, but that few can do so
for 30 seconds.

―One-Leg Stand is also administered and interpreted in a standardized
manner. Officers carefully observe the suspect‘s performance and look for
four specific clues:

―• sways while balancing;
―• uses arms to balance;
―• hops;
―• puts foot down.
―Inability to complete the One-Leg Stand test occurs when the suspect:
―• puts the foot down three or more times, during the 30-second period;
―• cannot do the test.
―The original research shows that, when the suspect produces two or more
clues or is unable to complete the test, it is likely that the BAC is above 0.10
[percent]. This criterion has been shown to be accurate 65 percent of the time.‖
(Utah Prosecution Manual, supra, ch. 8, at pp. 8–9 <
Documents/Sentencing/ProsecutionManual/chapter8.pdf> [as of April 6, 2015].)

In the Romberg test, the driver is ―asked to stand at attention, close his
eyes, tilt his head back, and estimate the passage of 30 seconds.‖ (People v.
(2012) 205 Cal.App.4th 26, 33.) The officer observes the driver‘s ―balance
and his ability to accurately measure the passage of 30 seconds.‖ (Ibid.)


all directions from center by 1–2 inches‖ and ―estimated 30 seconds at 37 actual
seconds.‖ Plaintiff refused to perform a preliminary alcohol screening, or PAS.6
Based on the officers‘ observations of plaintiff and her poor performance
on the field sobriety tests, they placed her under arrest at 2:00 a.m. Officer White
advised her of the implied consent law7 and she chose to perform a breath test,
although she failed several times to provide an adequate breath sample and had to
be retested multiple times. At 2:28 a.m., 56 minutes after she was stopped by
Sergeant Martin, her breath test registered a BAC of 0.08 percent. Three minutes
later, at 2:31 a.m., her second breath test measured a BAC of 0.09 percent. Police
then transported plaintiff to the Orange County jail, where she elected to have her
blood drawn. The blood draw occurred at 2:55 a.m., one hour 23 minutes after
plaintiff was pulled over by Sergeant Martin. The first test of the blood sample
showed a BAC of 0.095 percent; the second measured 0.096 percent. As a result
of these chemical test results, Officer White confiscated plaintiff‘s driver‘s license

Pursuant to section 23612, subdivision (h), a PAS is an investigative tool
used to determine whether there is reasonable cause for arrest. ―[A] preliminary
test is ‗distinguished from the chemical testing of a driver‘s blood, breath or urine
contemplated by the implied consent law [citation] which is administered after the
driver is arrested, [and is] sometimes referred to as ―evidentiary‖ [or evidential]
testing.‘ ‖ (People v. Vangelder (2013) 58 Cal.4th 1, 5, fn. 1.)

―A person who drives a motor vehicle is deemed to have given his or her
consent to chemical testing of his or her blood or breath for the purpose of
determining the alcoholic content of his or her blood, if lawfully arrested for an
offense allegedly committed in violation of Section 23140, 23152, or 23153.‖
(§ 23612, subd. (a)(1)(A).) ―The person shall be told that his or her failure to
submit to, or the failure to complete, the required chemical testing will result in a
fine, mandatory imprisonment if the person is convicted of a violation of Section
23152 or 23153, and . . . suspension or revocation of the person‘s privilege to
operate a motor vehicle . . . .‖ (§ 23612, subd. (a)(1)(D).)


and issued her an ―administrative per se suspension/revocation order‖ and
temporary driver‘s license. (§ 13382; see Lake v. Reed (1997) 16 Cal.4th 448,
454–455 (Lake).)
Plaintiff, charged with drunk driving (§ 23152), was allowed to plead to a
―wet reckless‖ (§§ 23103 [misdemeanor reckless driving], 23103.5 [prosecutorial
statement that alcohol was involved]; see People v. Claire (1991) 229 Cal.App.3d
647, 650 & fn. 2), but requested a hearing before the DMV to challenge her
license suspension (§ 13558).
At the ensuing administrative hearing, the DMV hearing officer had before
her the ―Officer‘s Sworn Statement‖ form, Officer White‘s arrest report and the
supplemental reports of Sergeant Martin and Officer White. In addition to
considering these documents, the hearing officer heard telephonic testimony from
Jay Williams, a forensic toxicologist with extensive experience, who testified for
plaintiff. Williams noted the result of plaintiff‘s first breath test was 0.08 percent,
the second test three minutes later was 0.09 percent, and her blood sample taken
about 20 minutes later tested at 0.095 and 0.096 percent. According to Williams,
these results suggested the alcohol level in plaintiff‘s body was rising at the time
of the tests and, given the totality of the circumstances, were consistent with
plaintiff‘s BAC being below 0.08 percent at 1:32 a.m. when she was first pulled
over by Sergeant Martin.
The DMV hearing officer rejected Williams‘s testimony regarding a rising
BAC, explaining in her ruling that the witness‘s two conclusions—first, that
plaintiff‘s BAC was rising at the time she was pulled over, and second, that it may
accordingly be deduced that her BAC was below 0.08 percent when she was
driving—were not supported by reliable evidence, were ―too speculative to
support the contention,‖ and were ―based on a subjective interpretation of the
evidence.‖ In addition, Williams‘s conclusions were ―insufficient to rebut the

official duty presumption,‖ which in this context we take to be a reference to the
presumption the chemical test results were valid.8 The hearing officer reached this
conclusion, she explained, because Williams had not himself examined the breath-
analyzing device used in the case, offered no opinion whether it was in working
order, conducted no scientific tests himself, and ―did not show that any other
experts in the scientific community had reached similar conclusions.‖ Finally, the
hearing officer specifically found credible Officer White‘s recordation of the
―events as they occur[red],‖ which we assume meant White‘s observations of
plaintiff‘s appearance and her performance on field sobriety tests. Accordingly,
the hearing officer concluded plaintiff‘s license suspension was proper because the
state had shown by a preponderance of the evidence that she had been driving with
a BAC of 0.08 percent or higher.
Plaintiff filed a petition for a writ of mandate with the trial court to
challenge the DMV hearing officer‘s decision. After first noting that section
23152, subdivision (b) makes it a rebuttable presumption that a person was driving
with a BAC of 0.08 percent or higher if so tested at that level or higher within
three hours of driving (see discussion, post), the trial court denied the writ,

Evidence Code section 664 provides in part: ―It is presumed that official
duty has been regularly performed.‖ Applied in this context, ―Evidence Code
section 664 creates a rebuttable presumption that blood-alcohol test results
recorded on official forms were obtained by following the regulations and
guidelines of [Cal. Code Regs.] title 17. [Citations.] Test results from authorized
laboratories, performed by public employees within the scope of their duties, are
admissible under the public employee records exception to the hearsay rule.
[Citations.] The recorded test results are presumptively valid and the DMV is not
required to present additional foundational evidence. [Citation.] At this point,
‗faced with a report of chemical test results, the burden would be on the licensee to
demonstrate that the test was not properly performed.‘ ‖ (Shannon v. Gourley
(2002) 103 Cal.App.4th 60, 64–65.)


explaining that ―[e]ven assuming that petitioner Coffey rebutted [this]
presumption . . . , there was sufficient evidence based on the blood-alcohol tests
and the other circumstantial evidence based on the assessment, observations and
tests by the arresting officers at the scene to support the DMV hearing officer‘s
decision under the weight of the evidence.‖ (Italics added.)
The Court of Appeal affirmed. In determining whether the trial court‘s
decision was supported by substantial evidence, the appellate court opined that
―[t]he issue boils down to whether non-chemical-test circumstantial evidence can
prove that Coffey‘s BAC at the time of driving was consistent with her BAC at the
time of her chemical tests.‖ Relying on this court‘s opinion in Burg v. Municipal
Court (1983) 35 Cal.3d 257, the appellate court held in the affirmative. We
granted review.
A. Background
The DMV suspended plaintiff‘s license to drive pursuant to the
―administrative per se‖ law, ―under which a person arrested for driving under the
influence of alcohol, and who is determined to have a prohibited amount of
alcohol in his or her blood, must have driving privileges suspended prior to an
actual conviction for a criminal offense.‖ (Lake, supra, 16 Cal.4th at p. 454.) As
we explained in that case, ― ‗[t]he express legislative purposes of the
administrative suspension procedure are: (1) to provide safety to persons using the
highways by quickly suspending the driving privilege of persons who drive with
excessive blood-alcohol levels; (2) to guard against erroneous deprivation by
providing a prompt administrative review of the suspension; and (3) to place no
restriction on the ability of a prosecutor to pursue related criminal actions.‘ ‖
(Ibid.) ―[T]he administrative per se laws were deemed necessary due to the time

lag that often occurs between an arrest and a conviction for driving while
intoxicated or with a prohibited BAC. During this interim period, arrestees who
could eventually be convicted of an intoxication-related driving offense were
permitted to continue driving and, possibly, endangering the public thereby.
Moreover, without administrative per se laws, persons with extremely high BAC
levels at the time of arrest could escape license suspension or revocation by plea
bargaining to lesser crimes or entering pretrial diversion. Thus, by providing for
an administrative license suspension prior to the criminal proceeding, the law
affords the public added protection.‖ (Id. at pp. 454–455.)
Pursuant to the administrative per se law, ―[a]fter either the arresting officer
or the DMV serves a person with a ‗notice of an order of suspension or revocation
of the person‘s [driver‘s license],‘ the DMV automatically reviews the merits of
the suspension or revocation. [Citation.] The standard of review is preponderance
of the evidence [citation], and the department bears the burden of proof.‖ (Lake,
supra, 16 Cal.4th at p. 455.) A driver served with such a suspension notice is
entitled to a hearing on request (§ 13558, subd. (a)), at which the only issues to be
decided for drivers such as plaintiff9 are whether the arresting officer had
reasonable cause to believe she was driving, whether she was arrested for an
enumerated offense, and whether she was driving with 0.08 percent BAC or
higher. (§ 13557, subd. (b)(3)(A), (B), & (C)(i).) If the DMV hearing officer
finds these three statutory prerequisites proved by a preponderance of the
evidence, the accused‘s driver‘s license will be suspended for four months if the

Somewhat different rules apply to those under 21 years of age (§ 13557,
subd. (b)(3)(C)(ii)), those driving commercial vehicles (id., subd. (b)(3)(C)(iv)),
and those on probation for prior drunk driving convictions (id., subd.


driver has had a clean driving record (§ 13353.3, subd. (b)(1)). Higher penalties
apply to those with prior drunk driving convictions. (§ 13353.3, subd. (b)(2).)
B. The Rebuttable Presumption in Section 23152
We first address whether the presumption created by section 23152,
subdivision (b) controls this case. That provision states in part: ―In any
prosecution under this subdivision, it is a rebuttable presumption that the person
had 0.08 percent or more, by weight, of alcohol in his or her blood at the time of
driving the vehicle if the person had 0.08 percent or more, by weight, of alcohol in
his or her blood at the time of the performance of a chemical test within three
hours after the driving.‖ Although the statutory language speaks in terms of a
―prosecution,‖ several Courts of Appeal have held this presumption is not limited
to criminal prosecutions but also applies in administrative license suspension
proceedings. (Corrigan v. Zolin (1996) 47 Cal.App.4th 230, 236, citing Jackson v.
Department of Motor Vehicles (1994) 22 Cal.App.4th 730, 740, fn. 9, and Bell v.
Department of Motor Vehicles (1992) 11 Cal.App.4th 304, 310–313.)
Extending the reach of Vehicle Code section 23152, subdivision (b)‘s
evidentiary presumption to administrative per se proceedings would be consistent
with the legislative history of that provision. The need for the presumption ―arose
from the absence in ‗[e]xisting law‘ of any ‗provision for the delay involved
between the time a person is arrested for [driving under the influence] and when
the chemical test for BAC is actually administered,‘ of any ‗means to determine a
person‘s BAC at the time the person is actually driving the car,‘ or of any
‗mention of time parameters for the administering of chemical tests and for their
admission as [admissible] evidence into a court of law.‘ (Health & Welf. Agency,
Dept. of Alcohol & Drug Programs, Enrolled Bill Rep. for Sen. Bill No. 745
(1981–1982 Reg. Sess.) Sept. 1982, original italics.) Thus, in enacting the

presumption, the Legislature intended (1) to ‗diminish the arguments that ha[d]
arisen when extrapolating the [BAC] at the time of the test back to the time of the
driving‘ (Bus. & Transportation Agency, DMV, Enrolled Bill Rep. for Sen. Bill
No. 745 (1981–1982 Reg. Sess.) Sept. 1982), (2) ‗to close a potential loophole in
the current law, whereby a person . . . could claim that he or she had consumed . . .
alcohol which had not yet been absorbed into the bloodstream while the person
was operating the vehicle, but which later raised the blood alcohol level‘
(Governor‘s Office, Dept. of Legal Affairs, Enrolled Bill Rep. for Sen. Bill No.
745 (1981–1982 Reg. Sess.) Sept. 1982), and (3) ‗to recognize that alcohol
concentrations dissipate over time, so that a person whose blood alcohol levels
exceed the permissible concentrations at the time of the test, was likely to have
had unlawfully high blood alcohol levels when driving . . . .‘ ‖ (Bell v.
Department of Motor Vehicles, supra, 11 Cal.App.4th at p. 311.) These three
statements of legislative intent would arguably apply to administrative per se
proceedings as well.
Consistent with the previously cited Court of Appeal cases, both parties
assume section 23152‘s presumption applies in administrative per se hearings. We
need not resolve that question, however, because even were the presumption
applicable, it was rebutted in this case. An explanation of how the presumption
operates can be found in the Evidence Code. Section 601 of that code provides:
―A presumption is either conclusive or rebuttable. Every rebuttable presumption
is either (a) a presumption affecting the burden of producing evidence or (b) a
presumption affecting the burden of proof.‖ Vehicle Code section 23152,
subdivision (b), by its terms, creates a rebuttable presumption, and we agree with
the parties that it establishes a presumption affecting the burden of producing
evidence, not the burden of proof. A statute transferring the burden of proof to a
driver facing a criminal charge of drunk driving would raise serious constitutional

questions (see Ulster County Court v. Allen (1979) 442 U.S. 140, 157 [a
permissive presumption is constitutional if, among other things, it ―does not shift
the burden of proof‖]; see People v. Gamache (2010) 48 Cal.4th 347, 376
[rejecting claim that jury instruction ―impermissibly alters the burden of proof,‖
explaining the ―instruction does not establish an unconstitutional mandatory
presumption in favor of guilt [citation] or otherwise shift or lower the
prosecution‘s burden of establishing guilt beyond a reasonable doubt‖]), and
although those concerns are inapplicable here because it is an administrative per se
proceeding, neither party argues for a different construction. (See People v.
Dubon (2001) 90 Cal.App.4th 944, 953 [―When a presumption is established to
facilitate the determination of the particular action in which the presumption is
applied, rather than to implement public policy, it is a presumption affecting the
burden of producing evidence.‖].)
A rebuttable presumption requires the trier of fact, given a showing of the
preliminary fact (here, that a chemical test result showed plaintiff had a BAC of
0.08 percent or more within three hours of driving), to assume the existence of the
presumed fact (here, that plaintiff had been driving with a prohibited BAC)
―unless and until evidence is introduced which would support a finding of its
nonexistence, in which case the trier of fact shall determine the existence or
nonexistence of the presumed fact from the evidence and without regard to the
presumption.‖ (Evid. Code, § 604.) In other words, if evidence sufficient to
negate the presumed fact is presented, the ―presumption disappears‖ (Craig v.
Brown & Root, Inc. (2000) 84 Cal.App.4th 416, 421) and ―has no further effect‖
(In re Heather B. (1992) 9 Cal.App.4th 535, 561), although ―inferences may
nevertheless be drawn from the same circumstances that gave rise to the
presumption in the first place‖ (Craig v. Brown & Root, Inc., supra, at p. 421; see

Evid. Code, § 604 [―Nothing in this section shall be construed to prevent the
drawing of any inference that may be appropriate‖]).
Assuming the results of her breath and blood tests gave rise to a
presumption she was driving with a BAC of 0.08 percent or more, plaintiff argues
the testimony of her expert witness, Jay Williams, supplied the necessary contrary
evidence sufficient to rebut the presumption. By contrast, the DMV argues
Williams‘s testimony was insufficient, arguing that evidence necessary to rebut
the presumption must be substantial, i.e., ― ‗reasonable in nature, credible, and of
solid value; it must actually be ―substantial‖ proof of the essentials which the law
requires in a particular case.‘ ‖ Asserting the DMV hearing officer‘s refusal to
credit Williams‘s views shows his testimony was insubstantial, the DMV argues
his testimony was accordingly insufficient to rebut the statutory presumption.
The DMV misapprehends Evidence Code section 604. That section
provides that evidence is sufficient to rebut a presumption if it ―would support a
finding of [the] nonexistence of‖ the presumed fact. (Italics added.) The most
reasonable meaning of this phrase is that if the predicate facts are found, Vehicle
Code section 23152‘s presumption will apply unless the driver presents evidence
which, if believed, ―would support a finding of [the] nonexistence of‖ the
presumed fact. This plain meaning of the statutory language is supported by the
Assembly Committee on Judiciary‘s comment on section 604, which states:
―Such a presumption is merely a preliminary assumption in the absence of
contrary evidence, i.e., evidence sufficient to sustain a finding of the nonexistence
of the presumed fact. If contrary evidence is introduced, the trier of fact must
weigh the inferences arising from the facts that gave rise to the presumption
against the contrary evidence and resolve the conflict. For example, if a party
proves that a letter was mailed, the trier of fact is required to find that the letter
was received in the absence of any believable contrary evidence. However, if the

adverse party denies receipt, the presumption is gone from the case. The trier of
fact must then weigh the denial of receipt against the inference of receipt arising
from proof of mailing and decide whether or not the letter was received.‖ (Assem.
Com. on Judiciary com., reprinted at 29B pt. 2, West‘s Ann. Evid. Code (1995 ed.)
foll. § 604, p. 59.)
Viewing the presumption in section 23152, subdivision (b) in this way, and
assuming without deciding that it applies in administrative per se proceedings,10
we find Williams‘s testimony was sufficient to rebut the presumption that
plaintiff‘s BAC was at least 0.08 percent at the time she was driving. Williams
was qualified as an expert in the field and his testimony was clear and direct. If
believed, his evidence would have justified a conclusion that plaintiff‘s BAC was
rising at the time of her chemical tests and was thus quite possibly below the 0.08
percent threshold at the time she had been driving. As a consequence, the DMV
was required to prove plaintiff‘s BAC at the time she was driving without resort to
the statutory presumption.
C. The Circumstantial Evidence of Plaintiff’s Intoxication Was
Relevant and Thus Admissible
Having found the statutory presumption in section 23152, subdivision (b),
even if applicable, does not control this case, we turn to the main issue presented
here: Did the DMV hearing officer properly admit and consider non-chemical-test

The Legislature might in the future wish to clarify whether it intends that
the evidentiary presumption in section 23152 applies in administrative per se
proceedings as well as in ―prosecutions.‖


evidence to reach her conclusion that plaintiff was driving with at least a 0.08
percent BAC?11
The crime of drunk driving is set forth in section 23152 and can be
established in two ways: Subdivision (a) states that ―[i]t is unlawful for a person
who is under the influence of any alcoholic beverage to drive a vehicle.‖ To prove
a violation under subdivision (a), the People must present evidence the driver‘s
alcohol consumption impaired his or her ability to drive. (People v. McNeal
(2009) 46 Cal.4th 1183, 1197.) Subdivision (b) offers an alternative method of
proof; it states that ―[i]t is unlawful for a person who has 0.08 percent or more, by
weight, of alcohol in his or her blood to drive a vehicle.‖ To prove a criminal
violation under subdivision (b), the People need not prove the accused‘s driving
ability was impaired or diminished, but only that the driver‘s BAC reached or
exceeded the prohibited level at the time the accused was driving.
The administrative per se law‘s license suspension provision, although not a
criminal matter, is linked to the second prong of section 23152.12 Thus, license

Plaintiff notes the DMV hearing officer failed to submit to cross-
examination so that it might be determined how she used the circumstantial
evidence to reach her conclusion to reject the testimony of expert witness Jay
Williams. This failure, she argues, violated her right to due process of law.
Although it seems extremely dubious that plaintiff‘s due process rights require the
hearing officer to testify and submit to plaintiff‘s cross-examination, the record in
any event reveals no objection on this ground or request that the officer testify.
Accordingly, plaintiff forfeited this claim.

We are not here concerned with the less typical administrative per se
provisions applicable to underage or commercial drivers, or those on probation for
drunk driving (see §§ 13353.2, subd. (a)(2) [person under 21 years old with a BAC
of 0.01 percent or greater], 13353.2, subd. (a)(3) [person driving a vehicle
requiring a commercial driver‘s license with a BAC of 0.04 percent or greater],
13353.2, subd. (a)(4) [person on probation for drunk driving with a BAC of 0.01
percent or greater]), or to adults who refuse to submit to, or complete, a chemical

(footnote continued on next page)

suspension under the administrative per se law does not require proof of a person‘s
impairment to safely operate a motor vehicle due to alcohol consumption, but only
that the person‘s BAC level was 0.08 percent or more. Section 13382, subdivision
(a) provides in pertinent part: ―If the chemical test results for a person who has
been arrested for a violation of Section 23152 or 23153 show that the person has
0.08 percent or more, by weight, of alcohol in the person‘s blood, . . . the peace
officer, acting on behalf of the [DMV], shall serve a notice of order of suspension
or revocation of the person‘s privilege to operate a motor vehicle personally on the
arrested person.‖ (Italics added.) In this case, the DMV presented the results of
four chemical tests showing plaintiff‘s BAC was at or above 0.08 percent. Given
the presentation of these facially qualifying chemical test results, did the hearing
officer abuse her discretion in concluding that non-chemical-test evidence was
relevant and thus admissible to bolster or corroborate the chemical test results?
Plaintiff argues reliance on the non-chemical-test circumstantial evidence
was improper because such evidence cannot by itself establish whether her BAC
was 0.08 percent, higher than 0.08 percent, or lower than that level. She cites to
scientific evidence showing that physical manifestations of alcohol intoxication
can occur at levels much lower than a BAC of 0.08 percent and that observable
physical symptoms correlate poorly to actual BAC levels. She also argues that
one study has shown that poor performance on field sobriety tests has a low
correlation to whether a driver‘s BAC is over 0.08 percent. (Hlastala, Polissar &

(footnote continued from previous page)

test as requested by a law enforcement officer (§ 13353) or to underage drivers
(§ 13388) or adults on probation for drunk driving (§ 13389) who refuse to submit
to a preliminary alcohol screening (§ 13353.1, subd. (a)).


Oberman, Statistical Evaluation of Standardized Filed Sobriety Tests (May 2005)
50 J. Forensic Science, No. 3, p. 662.)
Unmentioned is that some studies have reached a contrary conclusion. For
example, the National Highway Traffic Safety Administration (NHTSA) released
the results of a study in 1998 that evaluated the accuracy of the standardized field
sobriety test (SFST) battery at BACs below 0.10 percent. (Stuster and Burns,
Final Rep. to NHTSA, Validation of the Standardized Field Sobriety Test Battery
at BACs Below 0.10 Percent (1998).) The NHTSA‘s study found that the battery
of SFSTs, which includes three of the tests administered to plaintiff (the horizontal
gaze nystagmus test, the ―walk-and-turn test,‖ and the ―one-leg stand test‖), when
administered by a trained officer, are ―extremely accurate in discriminating
between BACs above and below 0.08 percent.‖ (Id., at p. v, italics added.) The
NHTSA‘s report expressly dispelled a common misapprehension ―that field
sobriety tests are designed to measure driving impairment.‖ (Id., at p. 28.)
According to the NHTSA, the SFST battery is instead designed specifically to
―provide statistically valid and reliable indications of a driver‘s BAC, rather than
indications of driving impairment.
We are not here attempting to resolve the scientific debate over the use of
SFSTs to predict BAC. As plaintiff acknowledges, the test for admissibility of
evidence is not a strict one: As a general matter, evidence may be admitted if
relevant (Evid. Code, § 350), and ― ‗[r]elevant evidence‘ means evidence . . .
having any tendency in reason to prove or disprove any disputed fact that is of
consequence to the determination of the action‖ (id., § 210). ― ‗ ―The test of
relevance is whether the evidence tends, ‗logically, naturally, and by reasonable
inference‘ to establish material facts . . . .‖ ‘ ‖ (People v. Wilson (2006) 38 Cal.4th
1237, 1245.) ―The trial court has broad discretion to determine the relevance of
evidence [citation], and we will not disturb the court‘s exercise of that discretion

unless it acted in an arbitrary, capricious or patently absurd manner.‖ (People v.
Jones (2013) 57 Cal.4th 899, 947.)
Past cases applying this standard have found circumstantial evidence of
intoxication may be admissible when later-administered chemical tests show a
BAC exceeding the legal limit. In Burg v. Municipal Court, supra, 35 Cal.3d 257
(Burg), decided at a time when the BAC threshold for drunk driving was 0.10
percent,13 we explained that the crime of drunk driving set forth in section 23152,
subdivision (b) ―prohibits driving a vehicle with a blood-alcohol level of 0.10
percent or higher; it does not prohibit driving a vehicle when a subsequent test
shows a level of 0.10 percent or more. Circumstantial evidence will generally be
necessary to establish the requisite blood-alcohol level called for by the statute. A
test for the proportion of alcohol in the blood will, obviously, be the usual type of
circumstantial evidence, but of course the test is not conclusive: the defendant
remains free to challenge the accuracy of the test result, the manner in which it
was administered, and by whom. (People v. Lewis (1983) 148 Cal.App.3d 614,
620; accord, Fuenning v. Superior Court (Ariz. 1983) 680 P.2d 121, 127. . .
[rejecting argument that analogous statute represents ‗substitution of a machine
test result for a jury verdict‘ because defendant is given an opportunity to
challenge accuracy of test result, and state must prove beyond a reasonable doubt
that defendant‘s blood-alcohol level was 0.10 percent at the time he was driving];
Cooley v. Municipality Anchorage (Alaska App. 1982) 649 P.2d 251, 254–255.)
Of course, both parties may also adduce other circumstantial evidence tending to

See former section 23152, subdivision (b), as amended by Statutes 1982,
chapter 1337, section 1, page 4961. The administrative per se law was enacted
several years later in 1998. (See Stats. 1998, ch. 118, § 4, pp. 757–758.)


establish that the defendant did or did not have a 0.10 percent blood-alcohol level
while driving. (See, e.g., Fuenning, supra, at p. 130.)‖ (Burg, supra, at p. 266,
fn. 10, italics added.)
Plaintiff would distinguish Burg, supra, 35 Cal.3d 257, as a case involving
a criminal drunk driving prosecution, not an administrative per se matter, but if
non-chemical-test circumstantial evidence of intoxication may be admissible in a
criminal case where the People‘s burden of proof is beyond a reasonable doubt, we
see no reason why such evidence would be categorically inadmissible in an
administrative proceeding where the People‘s burden of proof is only a
preponderance of the evidence. Decisions in the Courts of Appeal support this
conclusion. Thus, in McKinney v. Department of Motor Vehicles (1992) 5
Cal.App.4th 519, the Court of Appeal considered whether sufficient evidence
supported the suspension of a driver‘s license under the administrative per se law.
Citing Burg, the McKinney court noted that administration of a chemical test
(blood, breath or urine) ―is not the only means of establishing that a driver‘s
[BAC] was .08 or more. [¶] . . . [B]oth parties are free to introduce circumstantial
evidence bearing on whether the driver‘s [BAC] exceeded the permissible level.
[Citation.] ‗Evidence regarding the manner in which a defendant drove,
performed field sobriety tests, and behaved is admissible and relevant as tending
to establish that he did or did not have a 0.10 [now 0.08] [BAC] while driving.‘ ‖
(McKinney, at p. 526, fn. 6; see Jackson v. Department of Motor Vehicles, supra,
22 Cal.App.4th at p. 741 [―circumstantial evidence other than chemical test results
may properly be admitted to establish a driver had the proscribed level of blood-
alcohol at the time of the offense‖]; People v. Randolph (1989) 213 Cal.App.3d
Supp. 1, 7 [same].)
Plaintiff argues Burg, supra, 35 Cal.3d 257, is unpersuasive because, apart
from the single sentence referencing non-chemical-test circumstantial evidence,

the opinion does not elaborate on the use of such evidence to prove a driver‘s
BAC. But Burg‘s citation to Fuenning v. Superior Court, supra, 139 Ariz. 590
[680 P.2d 121] (Fuenning), following that sentence is significant.14 In that case, a
person charged with drunk driving argued that circumstantial evidence ―regarding
the manner in which he was driving, [and] the manner in which he performed the
field sobriety tests,‖ while relevant to the issue of whether he drove under the
influence of alcohol, was ―irrelevant to the question of whether he . . . [was]
driving with a .10% or greater BAC.‖ (Fuenning, supra, at p. 599.) The Supreme
Court of Arizona rejected the argument, explaining the evidence was relevant and
thus admissible: ―We agree with defendant that the only ultimate issue is whether
defendant had a BAC of .10% or greater. In each case in which a violation of [the
.10 percent BAC law] is charged, the state will present evidence of the test and the
issue will be whether the test results were an accurate measurement of the
defendant‘s BAC at the time of arrest. Typically, defendants will attack the
margin of error, the conversion rate, the calibration of the test instrument, the
technique used by the operator, the absorption and detoxification factors, etc.
Evidence of defendant’s conduct and behavior—good or bad—will be relevant to
the jury’s determination of whether the test results are an accurate measurement
of alcohol concentration at the time of the conduct charged. For instance, the test
in the case at bench was given several hours after the arrest and showed a .11%
BAC. Defendant attacked the results, presenting evidence regarding margin of

Fuenning was later superseded by statute on a different point of law. (See
State ex rel. McDougall v. Superior Court in and for County of Maricopa (1995)
181 Ariz. 202, 205–206 [888 P.2d 1389, 1392–1393].) This subsequent history
does not affect Fuenning‘s discussion of the admissibility of circumstantial
evidence of intoxication.


error, time lapse and other factors. Such evidence might raise considerable doubt
whether the test result of .11% indicated .10% or greater BAC at the time
defendant was arrested. Evidence that at that time the person charged smelled
strongly of alcohol, was unable to stand without help, suffered from nausea,
dizziness or any of the other ‘symptoms’ of intoxication would justify an inference
that a test administered some time after arrest probably produced lower readings
than that which would have been produced had the test been administered at the
moment of arrest. The converse is also true. Evidence that at the time of arrest
defendant was in perfect control, displayed none of the symptoms of intoxication
and had not driven in an erratic manner, is relevant to show that a reading of .11%
from a test given some time later does not prove beyond a reasonable doubt that
the defendant was driving with a .10% or greater BAC at the time of his arrest.
Such evidence has been held admissible. [Citations.] Again, evidence is
admissible when it is relevant.‖ (Fuenning, supra, at p. 599, italics added.)
Plaintiff argues Fuenning is neither controlling nor even on point because it
did not address the issue before us in the instant case. Although Fuenning is an
Arizona case and thus admittedly not controlling here (see Farmers Ins. Group v.
County of Santa Clara (1995) 11 Cal.4th 992, 1018), it persuasively explains why
circumstantial evidence of intoxication, while not dispositive, may be relevant and
thus admissible15 to help interpret the results of a chemical test for a driver‘s
BAC. Moreover, because the Legislature has prohibited driving with a BAC of
0.08 percent or higher, that being the threshold at which a person cannot safely
operate a motor vehicle due to alcohol consumption, circumstantial evidence that
plaintiff was weaving erratically all over the roadway, smelled strongly of alcohol,

To the extent plaintiff argues Fuenning, supra, 139 Ariz. 590, did not
address the admissibility issue, she is simply incorrect.

and failed a battery of field sobriety tests may bolster chemical test results
showing that she had attained or exceeded that BAC level.
The administrative per se scheme in section 13382 is triggered by a
chemical test result showing a BAC of 0.08 percent or more, and we do not here
confront a case in which the DMV failed to present such test results; indeed, the
DMV produced the results of four such tests. In other words, neither the DMV
hearing officer nor the trial court considered circumstantial evidence of
intoxication in the absence of any chemical test results. Although we find non-
chemical-test evidence of plaintiff‘s intoxication may be relevant and thus
admissible in the typical administrative per se proceeding triggered by a BAC of
0.08 percent or more to help connect those test results to a driver‘s BAC at the
time she was driving (subject, of course, to the hearing officer‘s routine exercise
of discretion), we would in any event affirm the hearing officer‘s decision in this
case because the non-chemical-test evidence was admissible to rebut plaintiff‘s
proffered defense that her BAC was low at the time she was driving and only later
rose to exceed the legal limit. Her expert, Jay Williams, testified that, in his
opinion, the four chemical test results indicated plaintiff‘s BAC was rising at the
time of the tests; from that supposition, he further deduced that plaintiff‘s BAC
was below the 0.08 percent threshold at the time she was driving. Even assuming
that non-chemical-test evidence cannot by itself prove a driver‘s exact BAC at the
moment the driver is stopped by a police officer, in this case plaintiff‘s erratic
driving, outward appearance of substantial intoxication, implausible story of
having just turned 21 years old, and was coming from a bar without having
imbibed alcohol at all, and her failure on multiple field sobriety tests, together tend
to rebut Williams‘s theory of a rising BAC and corroborate the BAC test results.
For example, plaintiff‘s extremely erratic driving, observed by Sergeant Martin
from before the moment he first made contact with her, suggests she was quite

intoxicated from that early point in the timeline and tends to refute the expert‘s
speculation that her BAC was low at the time she was driving, but rose to 0.08
percent and above only after she was stopped. Whether the circumstantial
evidence of plaintiff‘s intoxication was admitted to bolster the results of the
chemical tests or merely to rebut plaintiff‘s defense of a rising BAC, the hearing
officer did not act in ―an arbitrary, capricious or patently absurd manner‖ and thus
did not abuse her broad discretion. (People v. Jones, supra, 57 Cal.4th at p. 947.)
Brenner v. Department of Motor Vehicles (2010) 189 Cal.App.4th 365,
cited by plaintiff, does not warrant a contrary result. In that case, an expert
examined the maintenance records for the device used to measure the driver‘s
breath and opined that it produced slightly elevated results. As the driver‘s test
results showed a BAC of 0.08 percent exactly, the expert opined the driver‘s
actual BAC was slightly below the legal limit. Because the trial court in Brenner
had granted the driver‘s petition for a writ, the Court of Appeal was required to
uphold that decision if supported by substantial evidence. By contrast, the instant
case comes to us in the opposite procedural posture: the trial court here denied
relief to plaintiff and we are bound to uphold that decision if supported by
substantial evidence. To the extent the appellate court in Brenner asserted that
―the impressions of the officer may have a bearing on plaintiff‘s level of
impairment, [but] they have no bearing on the precise level of his BAC‖ (id. at
p. 373), the statement must be read in the context of the case: Because the
chemical tests in Brenner were done on a miscalibrated device used to measure the
BAC in a breath sample, no accurate chemical test results were presented. No
such problem exists in the instant case; the DMV presented the results of four
chemical tests and, although plaintiff‘s expert would have interpreted those results
to conclude her BAC was rising, he did not testify they inaccurately measured her
BAC at the time the tests were run. To the extent the court‘s statement in Brenner

v. Department of Motor Vehicles, supra, 189 Cal.App.4th 365, may be taken to
preclude consideration of non-chemical-test evidence to bolster or corroborate
chemical test results, we disapprove it.
Having concluded the DMV hearing officer properly admitted the
circumstantial, nontest evidence of plaintiff‘s intoxication, we also conclude
substantial evidence supported the trial court‘s decision to deny writ relief, thereby
sustaining the DMV hearing officer‘s decision to suspend plaintiff‘s license to
drive. A driver whose license has been suspended under the administrative per se
law can seek review of the DMV‘s decision by seeking a writ of mandate in the
trial court. ―In ruling on an application for a writ of mandate following an order of
suspension or revocation, a trial court is required to determine, based on its
independent judgment, ‗ ―whether the weight of the evidence supported the
administrative decision.‖ ‘ ‖ (Lake, supra, 16 Cal.4th at p. 456.) Following the
trial court‘s denial of the writ, the scope of our review on appeal is limited: ―[W]e
‗need only review the record to determine whether the trial court‘s findings are
supported by substantial evidence.‘ [Citation.] ‗ ―We must resolve all evidentiary
conflicts and draw all legitimate and reasonable inferences in favor of the trial
court‘s decision. [Citations.] Where the evidence supports more than one
inference, we may not substitute our deductions for the trial court‘s. [Citation.]
We may overturn the trial court‘s factual findings only if the evidence before the
trial court is insufficient as a matter of law to sustain those findings.‖ ‘ ‖ (Lake,
supra, at p. 457.)
Applying this standard, we have no trouble concluding substantial evidence
supported the trial court‘s ruling, for it acted well within its discretion in rejecting
the expert‘s testimony and placing primary emphasis on the four chemical tests
that showed plaintiff‘s BAC met or exceeded the statutory threshold at the time
plaintiff was driving. Neither the DMV hearing officer nor the trial court was

required to accept Williams‘s testimony at face value. (People v. Prince (1988)
203 Cal.App.3d 848, 858 [trier of fact ―is permitted to consider the credibility of
the expert witnesses, the reasons given for their opinions, and the facts and other
matters upon which their opinions are based‖]; cf. CALCRIM No. 332 [instructing
the jury it is not required to accept a proffered expert opinion as ―true or
correct‖].) Both reasonably relied on circumstantial evidence of plaintiff‘s
intoxication—her general appearance, the odor of alcohol about her person, her
erratic driving, and her failed field sobriety tests—to support the accuracy of the
chemical test results and to reject Williams‘s view of the evidence, including his
opinion of a rising BAC, as unduly speculative.

The judgment of the Court of Appeal is affirmed.




I write separately to clarify the limited way in which evidence of behavioral
impairment was relevant in this case to determining whether the driver‘s blood-
alcohol concentration (BAC) was 0.08 percent or higher at the time of arrest.
― ‗Relevant evidence‘ means evidence . . . having any tendency in reason to
prove or disprove any disputed fact that is of consequence to the determination of
the action.‖ (Evid. Code, § 210.) Evidence that a driver‘s behavior is not
impaired tends to prove that her BAC was below 0.08 percent because we can
rationally surmise, given the Legislature‘s choice of the 0.08 percent BAC
threshold, that a BAC of 0.08 percent is associated with an unsafe degree of
impairment. But the converse is not true. Absent foundational evidence, a
driver‘s impairment does not generally tend to show that her BAC was 0.08
percent or higher because we have no way of correlating a specific type or degree
of impairment with a particular BAC in a close case. The fact that 0.08 percent
BAC is a threshold associated with an unsafe degree of impairment does not imply
that no impairment occurs below that threshold. Without evidence that correlates
particular behavioral impairments with particular BAC levels, signs of impairment
do not generally establish that it is more likely a driver‘s BAC is 0.08 percent as
opposed to 0.06 or 0.07 percent. In other words, signs of impairment do not
generally have a tendency in reason to prove a BAC of 0.08 percent or greater.

I say ―generally‖ because sometimes evidence of impairment can be so
extreme — for example, if the driver passed out at the scene of arrest — that the
trier of fact may infer on the basis of common experience that the driver likely was
driving with a BAC of 0.08 percent or higher. But there is no evidence of such
extreme impairment in this case.
Today‘s opinion properly refrains from suggesting that there is a correlation
between evidence of impairment, including field sobriety test results, and a BAC
of 0.08 percent or greater. The court cites a study commissioned by the National
Highway Traffic Safety Administration (NHTSA) reporting that at least some field
sobriety tests, properly administered, may accurately measure a BAC of 0.08
percent or greater. (Stuster and Burns, Final Rep. to NHTSA, Validation of the
Standardized Field Sobriety Test Battery at BACs Below 0.10 Percent (1998)
p. v.) But today‘s opinion is careful to express no view about the merits of these
claims (maj. opn., ante, at p. 17), and other courts have questioned them. In
United States v. Horn (D.Md. 2002) 185 F.Supp.2d 530, for example, the court
undertook an extensive review of expert testimony and academic literature
critiquing an earlier NHTSA study and concluded that ―presently there is
insufficient data to support these claims of accuracy‖ of field sobriety tests in
predicting BAC. (Id. at p. 556.)
This lack of correlation between evidence of impairment and BAC does not
mean that such evidence is always irrelevant. As the New Mexico Supreme Court
has explained, ―behavioral evidence by itself cannot be sufficient to show the
required nexus between a BAC test and an earlier BAC. It may, however, have
limited relevance when the factors that underlie the shape of the concentration
time curve [showing the level of alcohol absorption over time] are subject to
conflicting testimony.‖ (State v. Day (N.M. 2008) 176 P.3d 1091, 1100.)

That is precisely how such evidence is relevant in this case. The results of
the four tests of Ashley Coffey‘s BAC indicated that it was rising, and the parties
offer competing explanations. Coffey argues that her BAC was in fact rising and
that her BAC must have been below 0.08 percent at the time of her arrest. By
contrast, the Attorney General attributes the rising BAC test results to the test‘s
margin of error (which would explain the 0.01 percent rise within three minutes
between the first and second breath tests) and to the fact that the last two tests
were blood tests rather than breath tests and thus produced slightly different
results. The Attorney General asserts that the testimony of Coffey‘s expert, Jay
Williams, lacked key findings to support a rising BAC theory, such as when
Coffey had her last drink before getting behind the wheel, her food intake, her
weight, and other factors. As the Department of Motor Vehicles (DMV) hearing
officer concluded, Williams did not show that other experts in the scientific
community had reached similar conclusions based on facts similar to those in this
Evidence of Coffey‘s impairment was relevant to deciding which theory of
rising BAC was more likely correct. Such evidence was relevant in the following
limited sense: The fact that Coffey did show signs of impairment made her theory
of rising BAC weaker than if Coffey had not shown signs of impairment at the
time of her arrest. (See maj. opn., ante, at p. 22 [―[T]he non-chemical-test
evidence was admissible to rebut plaintiff‘s proffered defense that her BAC was
low at the time she was driving and only later rose to exceed the legal limit.‖].)
This point, on which all members of the court agree, renders unnecessary any
broader suggestion that in a typical administrative per se proceeding, evidence of a
driver‘s impairment tends to prove a BAC level of 0.08 percent or higher at the
time of arrest. Here the evidence of Coffey‘s impairment was, like the other

weaknesses in the expert‘s testimony discussed above, relevant to the DMV
hearing officer‘s conclusion that the rising BAC theory was ―too speculative.‖
Because the evidence of Coffey‘s impairment was relevant in the limited
way just described, and because the evidence is sufficient to support the
determinations of the DMV hearing officer and the trial court that Coffey drove
with a BAC at or above 0.08 percent, I concur in the judgment.

See next page for addresses and telephone numbers for counsel who argued in Supreme Court.

Name of Opinion Coffey v. Shiomoto

Unpublished Opinion

Original Appeal
Original Proceeding
Review Granted
XXX 218 Cal.App.4th 1288
Rehearing Granted


Opinion No.

Date Filed: April 6, 2015


County: Orange
Judge: Robert J. Moss



Law Offices of Chad R. Maddox and Chad R. Maddox for Plaintiff and appellant.

Kamala D. Harris, Attorney General, Alicia M.B. Fowler, Kenneth C. Jones and Kevin K. Hosn, Deputy
Attorneys General, for Defendant and Respondent.


Counsel who argued in Supreme Court (not intended for publication with opinion):

Chad R. Maddox
Law Offices of Chad R. Maddox
5120 E. La Palma, #207
Anaheim Hills, CA 92807
(714) 695-1500

Kevin K. Hosn
Deputy Attorney General
300 South Spring Street, Suite 1702
Los Angeles, CA 90013
(213) 897-2091


Opinion Information
Date:Docket Number:
Mon, 04/06/2015S213545