2014 IL App (2d) 120507
No. 2-12-0507
Opinion filed March 28, 2014
______________________________________________________________________________
IN THE
APPELLATE COURT OF ILLINOIS
SECOND DISTRICT
______________________________________________________________________________
THE PEOPLE OF THE STATE ) Appeal from the Circuit Court
OF ILLINOIS, ) of Kane County.
)
Plaintiff-Appellee, )
)
v. ) No. 11-CF-1221
)
CHRYSTAL L. FLOYD, ) Honorable
) Marmarie J. Kostelny,
Defendant-Appellant. ) Judge, Presiding.
______________________________________________________________________________
JUSTICE HUTCHINSON delivered the judgment of the court, with opinion.
Justices McLaren and Hudson concurred in the judgment and opinion.
OPINION
¶1 Following a jury trial, defendant, Chrystal L. Floyd, was convicted of aggravated driving
under the influence (DUI) pursuant to section 11-501(a)(2) of the Illinois Vehicle Code (625
ILCS 5/11-501(a)(2) (West 2010)) and resisting arrest (720 ILCS 5/31-1(a) (West 2010)).
During the trial, the State introduced expert witness testimony on a “retrograde extrapolation”
calculation in an attempt to demonstrate that defendant’s blood alcohol concentration (BAC) was
at or above 0.08 at the time of her arrest. Retrograde extrapolation is premised on the theory that
a person’s BAC, derived from a breath or blood test at a particular time, can be extrapolated back
to an allegedly higher BAC that existed at the time of a prior incident. The State also introduced
2014 IL App (2d) 120507
evidence of other crimes that occurred before defendant allegedly committed the offense of
aggravated DUI.
¶2 On appeal, defendant contends that the trial court erred by (1) allowing the expert
witness’s testimony on retrograde extrapolation when the expert did not have information
necessary to conduct a reliable calculation; (2) allowing the State to admit other-crimes evidence
that was highly prejudicial, but minimally relevant; (3) allowing testimony, which lacked
foundation, that defendant failed a horizontal gaze nystagmus (HGN) test; and (4) failing to
instruct the jury that it could not draw a negative inference from the State’s video recording of
defendant’s field sobriety tests, which the State failed to produce. For the following reasons, we
reverse defendant’s DUI conviction and remand for a new trial.
¶3 The record reflects that, on June 16, 2011, defendant was in the parking lot at the Dolphin
Cove Family Aquatic Center in Carpentersville. At approximately 7:30 p.m., defendant made a
911 call via the OnStar system in her vehicle. Defendant told the 911 operator that she had a
“violent boyfriend” who wanted to hit and rob her. Defendant can be heard on the recording
telling a man that she had been “drinking since I’ve been here.” Defendant then told the operator
that a man who made her perform oral sex on him was sitting in her vehicle and that “he needs to
get the [expletive] out of my car.” Officer David Rowley was dispatched to the Dolphin Cove
parking lot. Upon arriving, he observed defendant and a man arguing outside of a vehicle.
Because Rowley believed that defendant was intoxicated, he told her not to drive. At that point,
defendant and the man went separate ways, and Rowley left the scene.
¶4 Thereafter, Mike Eschenbach, the manager of Dolphin Cove, noticed that defendant was
back inside her vehicle. Defendant was alone, sitting in the passenger seat, and listening to loud
music. Eschenbach observed a man approach defendant’s vehicle, and the man then “tossed
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2014 IL App (2d) 120507
something at the vehicle, gave it a light shake, and walked away.” Eschenbach left the Dolphin
Cove parking lot at approximately 8:30 p.m.
¶5 At around 8:50 p.m., Don Azerela, the building supervisor, witnessed a man approach
defendant’s vehicle. About a minute later, Azerela heard the man pounding on defendant’s
vehicle and saw the vehicle shake. Azerela moved closer to the parking lot and was joined by
Scott McManus. As the man was shaking the vehicle, Azerela and McManus witnessed the
vehicle’s brake lights come on and heard the engine start. A chase ensued and McManus called
911. Azerela estimated that the vehicle reached a speed of 25 miles per hour during the chase.
When the man ran toward a gas station, defendant’s vehicle turned back and returned to its
original parking space. The police arrived about a minute later.
¶6 Officer Robert Drews arrived at the scene and observed skid marks leading to the parked
vehicle. The key was in the ignition, but the engine was not running, and defendant appeared to
be sleeping in the driver’s seat. Drews knocked on the window, and when defendant opened the
vehicle’s door, Drews could smell a “moderate” odor of alcohol. According to Drews,
defendant’s speech was “good,” and her eyes were not bloodshot or glassy. Defendant told
Drews that she had not been driving, because she was too drunk to drive. Drews advised
defendant that she needed to perform sobriety tests, but defendant refused and began to walk
away. Drews attempted to arrest defendant, but she resisted; Drews and his partner effected the
arrest and placed her into the squad vehicle. A tow truck subsequently towed defendant’s
vehicle.
¶7 At the police station, defendant agreed to perform field sobriety tests. Defendant passed
a one-legged-stand test but failed a walk-and-turn test. Drews also tested defendant’s eyes for
the presence of HGN. The test looks for three clues per eye: (1) the lack of a smooth pursuit as a
stimulus is moved from directly ahead of the subject to the subject’s periphery; (2) the presence
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of a “distinct nystagmus at maximum deviation” when the stimulus is held as far out to the
periphery as the eye can follow; and (3) the onset of nystagmus before the eye has rotated 45
degrees as it follows the stimulus toward the periphery. The maximum number of clues that can
be detected is six, with three clues for each eye. Drews determined that four clues were present
and concluded that defendant was under the influence of alcohol.
¶8 All three tests were performed in the police station’s booking area. The booking area
contained video recording devices in the booking room, the sally port, and the hallway leading to
the booking room.
¶9 Law enforcement officers administered a breath test to defendant at 10:30 p.m., which
registered her BAC at 0.069. At trial, the State produced John Wetstein, a forensic toxicologist,
as an expert witness. Wetstein testified that, after conducting a retrograde extrapolation
calculation, he determined that defendant’s BAC at 9:10 p.m. was between 0.082 and 0.095.
¶ 10 Wetstein explained that conducting a retrograde extrapolation calculation is possible
because a person eliminates alcohol at a fixed rate of between 0.01 and 0.02 grams per deciliter
of blood per hour. Wetstein explained that two conditions must be met for the calculation to be
valid. First, the person metabolizes alcohol at the normal rate. Second, the person is in the
postabsorption phase—that is, the person is no longer absorbing alcohol and is in the elimination
phase—when the breath test is administered. Wetstein explained that, because the body absorbs
alcohol primarily through the small intestine, a person’s absorption rate will vary depending on
many factors. These factors include the type of food that the person has eaten, the type of
alcohol consumed, and the length of time during which the drinking occurred. Wetstein testified
that after a person’s last drink a person can take from 15 minutes to 90 minutes or more to enter
the postabsorption phase.
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¶ 11 On cross-examination, Wetstein acknowledged that he did not know what defendant had
eaten that night, how long she had been drinking, or what type of alcohol she consumed.
Wetstein admitted that he did not attempt to determine when defendant had entered the
elimination phase, but rather assumed that she was in the elimination phase at 9:10 p.m.
Wetstein explained that, if a person had not consumed any alcohol since 7:30 p.m., he would be
“quite confident” that the person was in the elimination phase by 9:10 p.m.
¶ 12 The jury found defendant guilty of aggravated DUI and resisting arrest. Based on two
prior burglary convictions, the trial court sentenced defendant as a Class X offender to the
minimum of six years’ imprisonment. Defendant appeals her DUI conviction but not her
resisting arrest conviction.
¶ 13 Defendant’s first contention on appeal is that the trial court erred in admitting Wetstein’s
testimony regarding Wetstein’s retrograde extrapolation calculation. Defendant argues that,
because Wetstein did not have information necessary to perform a retrograde extrapolation
calculation with any degree of certainty, the prejudicial effect of his testimony outweighed its
probative value. Specifically, defendant argues that Wetstein did the “simple part” of the
retrograde extrapolation calculation by adding between 0.01 and 0.02 per hour to the result of
defendant’s breath test, but he “assumed away” that defendant was in the postabsorption,
elimination phase. Thus, the gravamen of defendant’s argument is that, because a subject being
in the elimination phase is necessary for a retrograde extrapolation calculation to be accurate and
valid, Wetstein’s testimony had little probative value because he merely assumed that defendant
was in that phase. Further, Wetstein’s testimony was prejudicial because, as a “court-
pronounced expert regarding retrograde extrapolation,” the jury would “listen[] to him anyway.”
¶ 14 The admissibility of evidence rests in the trial court’s sound discretion, and its ruling will
not be reversed absent an abuse of discretion. People v. Montes, 2013 IL App (2d) 111132, ¶ 61.
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Under Illinois Rules of Evidence 401 and 402 (eff. Jan. 1, 2011), relevant evidence, i.e.,
evidence that has a tendency to prove or disprove a fact of consequence, is admissible at trial.
Nonetheless, relevant evidence may be excluded if its prejudicial effect substantially outweighs
its probative value. Ill. R. Evid. 403 (eff. Jan. 1, 2011); People v. Hoerer, 375 Ill. App. 3d 148,
157 (2007). Thus, in deciding whether to admit evidence, the trial court must weigh the
evidence’s prejudicial effect against its probative value. Hoerer, 375 Ill. App. 3d at 157 (citing
People v. Walker, 211 Ill. 2d 317, 338 (2004)).
¶ 15 In support of her contention, defendant cites State v. Eighth Judicial District, 267 P.3d
777 (Nev. 2011) (Armstong). In Armstrong, the Nevada Supreme Court considered whether the
trial court erred in excluding a retrograde extrapolation calculation to estimate the defendant’s
BAC. Id. at 778-79. The defendant was involved in a vehicular accident at 1:30 a.m. Id. at 779.
A single blood sample was taken at 3:51 a.m. and reflected the defendant’s BAC as 0.18. Id.
After an evidentiary hearing, the trial court granted the defendant’s motion to exclude the
retrograde extrapolation calculation. Id.
¶ 16 In determining whether the trial court erred in excluding the evidence, the Nevada
Supreme Court noted that a retrograde extrapolation calculation required information on the rates
at which alcohol was absorbed and excreted. Id. at 780. It further noted that rates can vary
depending on a number of factors, including the elapsed time between a person’s last drink and
the blood test; the amount and type of alcohol consumed; the time period during which the
alcohol was consumed; and personal characteristics such as age, weight, alcohol tolerance, and
food intake. Id.
¶ 17 After determining that retrograde extrapolation evidence was relevant, the Nevada
Supreme Court turned to whether the evidence unfairly prejudiced the defendant. Id. at 781.
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2014 IL App (2d) 120507
The reviewing court noted that the trial court’s concern centered on the unknown variables,
which suggested:
“[T]he evidence [was] of little probative value given those variables and the single
[blood] sample, but the evidence [was] likely to move the jury to declare guilt based
solely on a reaction to the [BAC] and the very real devastation caused by drunk driving
rather than proof that the defendant was driving under the influence or with a prohibited
blood alcohol level.” Id. at 781-82.
After discussing case law from another jurisdiction, the court in Armstrong opined that
“achieving a reliable extrapolation calculation requires consideration of a variety of factors.” Id.
at 783. Those factors include a subject’s (1) gender; (2) weight; (3) age; (4) height; and (5)
mental state; (6) the type and amount of food in the stomach; (7) the type and amount of alcohol
consumed; (8) the time the last alcoholic drink was consumed; (9) the subject’s drinking pattern
at the relevant time; (10) the elapsed time between the first drink and the last drink consumed;
(11) the elapsed time between the last drink and the blood draws; (12) the number of samples
taken; (13) the elapsed time between the offense and the blood draws; (14) the average alcohol
absorption rate; and (15) the average elimination rate. Id. Turning to the case before it, the
Nevada Supreme Court noted that experts calculated the defendant’s BAC on factors attributed
to the “average person” and “various hypothetical situations.” Id. The reviewing court noted
that some of the above factors were known, such as that the defendant consumed two beers
between 5 p.m. and 10 p.m., that he weighed 212 pounds, and the elapsed time between the
accident and the blood draw. Id. However, there was no evidence concerning the defendant’s
age or height; the type and amount of food in his stomach; and his emotional state after the
accident. Id. In addition, the defendant gave one blood sample. The reviewing court noted that,
although one sample could result in a reliable retrograde extrapolation calculation if an expert
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2014 IL App (2d) 120507
has knowledge of many other personal characteristics and behaviors of the defendant, a single
blood draw, without more information, made it “difficult to determine whether [the defendant]
was absorbing or eliminating alcohol at the time of the blood draw.” Id. (citing Mata v. State, 41
S.W.3d 902, 916 (Tex. Crim. App. 2001)). The court in Armstrong concluded:
“The admission of retrograde extrapolation evidence when a single blood draw was taken
more than two hours after the accident is insufficiently tethered to individual factors
necessary to achieve a reliable calculation [and] potentially invites the jury to determine
[the defendant’s] guilt based upon emotion or an improper ground—that the defendant
had a high blood alcohol level several hours later—rather than a meaningful evaluation of
the evidence.” Id.
Thus, the reviewing court determined that the trial court did not abuse its discretion in excluding
the retrograde extrapolation evidence. Id.
¶ 18 The State, conversely, cites Petraski v. Thedas, 382 Ill. App. 3d 22 (2008). In Petraski,
Margaret Petraski was seriously injured in an accident with a vehicle driven by an officer in the
Cook County sheriff’s department; a jury awarded her in excess of $26 million. Id. at 23-24. At
trial, the defendants sought to introduce expert witness testimony that Petraski’s BAC would
have been above the legal limit at the time of the accident. Id. at 25. The expert would have
testified that, based on a blood test taken 90 minutes after the accident, Petraski had a blood
serum reading of 0.116 grams per deciliter. Id. After conducting a conversion, the expert would
testify that Petraski’s BAC at the time of the accident was approximately 0.095 or 0.096. Id. at
25-26. The expert would testify that he assumed that Petraski was in the elimination phase
during the entire period after the accident, and with that assumption he could perform a
retrograde extrapolation calculation. Id. at 26. The trial court excluded the evidence as being
too speculative. Id.
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2014 IL App (2d) 120507
¶ 19 On appeal, the reviewing court reversed the trial court’s exclusion of the retrograde
extrapolation calculation. The reviewing court concluded:
“We do not believe [the expert’s] assumption that Petraski’s [BAC] was in the
elimination phase when her blood was drawn [was] unwarranted. The blood draw took
place at least [an hour and a half] after the collision, most probably longer than that.
Nowhere in [the expert’s] proposed testimony was he asked to offer an estimate of
Petraski’s [BAC] level if she were in the absorption phase at the time of the draw. Nor
did the plaintiff offer any such evidence.” Id. at 31-32.
The reviewing court concluded that any questions regarding the facts upon which the expert
based his opinion would go to the weight of his opinion, which could be challenged on cross-
examination. Id. at 32. The reviewing court further concluded that the expert’s testimony,
which would have created a presumption of intoxication, would have been “extremely probative
of whether [Petraski] was partially at fault for the accident,” particularly when the jury had
already concluded that Petraski was 25% negligent. Id. With respect to unfair prejudice, the
reviewing court found that there was an “insubstantial risk” that the jury would have misused the
evidence. Id. at 33. Thus, the reviewing court reversed and remanded for a new trial. Id.
¶ 20 We are persuaded by the Nevada Supreme Court’s thoughtful and detailed reasoning in
Armstrong. A retrograde extrapolation calculation based on a single breath test, and when many
of the factors necessary to determine whether the defendant was in the elimination phase are
unknown, is insufficient to provide a reliable calculation and invites the jury to determine guilt
on an improper basis. Based on the specific circumstances presented in this case, we believe that
the prejudicial effect of the retrograde extrapolation calculation substantially outweighed its
probative value and that the trial court abused its discretion in admitting it.
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¶ 21 Before weighing the probative value of the retrograde extrapolation calculation against its
prejudicial effect, we first address the State’s argument that, because Illinois follows the test
enunciated in Frye v. United States, 293 F. 1013 (D.C. Cir. 1923), a trial court does not have the
discretion to exclude scientific evidence due to its prejudicial effect resulting from gaps in the
scientific evidence. Under the Frye standard, scientific evidence is admissible only if the
methodology or scientific principle is sufficiently established to have gained general acceptance
in a particular field. In re Commitment of Simons, 213 Ill. 2d 523, 529-30 (2004) (citing Frye,
293 F. at 1014). “General acceptance” does not mean universal acceptance; and the
methodology in question does not need to be accepted by unanimity, consensus, or a majority of
experts. Id. at 530. Rather, the underlying method used to generate an expert’s opinion must be
reasonably relied on by other experts in the relevant field. Id.
¶ 22 While we recognize that Illinois courts follow the Frye standard for the admission of
scientific evidence (see People v. Caballes, 221 Ill. 2d 282, 334 n.1 (2006)), the State’s assertion
that the Frye standard precludes a trial court from weighing the probative value of scientific
evidence against its prejudicial effect is misplaced. Our supreme court has held that, even if a
particular type of scientific evidence has been generally accepted in the scientific community, its
admissibility “in an individual case will depend on the State’s ability to lay a proper foundation
and to demonstrate the qualifications of its witness, subject to the balancing of probative value
with the risk of unfair prejudice.” (Emphasis added.) People v. McKown, 236 Ill. 2d 278, 314
(2010). We further note that, while other Illinois courts have held that retrograde extrapolation
evidence is admissible so long as it is presented by a qualified expert (People v. Ikerman, 2012
IL App (5th) 110299, ¶ 38), defendant did not raise the issue of whether retrograde extrapolation
evidence satisfies Frye. Therefore, we emphasize that our opinion today does not speak to that
question.
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2014 IL App (2d) 120507
¶ 23 With respect to the retrograde extrapolation’s probative value, we recognize that
Wetstein’s calculation would be relevant to whether defendant’s BAC was at or above 0.08.
Nonetheless, the inherent unreliability of Wetstein’s calculation is reflected in his own
testimony. Specifically, Wetstein testified that determining whether a person was in the
elimination phase was a “complicated question.” Wetstein testified that different circumstances
could affect whether someone was in the elimination phase, such as when the person started and
stopped drinking; a person’s eating and drinking habits; how much and what food had been
consumed; and the type of alcohol consumed. Wetstein acknowledged that he did not recall
when defendant started and stopped drinking. He testified that, if other relevant information on
whether defendant was in the elimination phase were available, he would have factored it into his
calculation. However, Wetstein’s testimony is devoid of any indication that he considered any
other information to determine whether defendant was in the elimination phase. Instead,
Wetstein admitted that his “big assumption” was that defendant was eliminating alcohol when
law enforcement officers administered the breath test, and he admitted that if his assumption
were wrong “the extrapolation [would not] be valid.” Thus, because Wetstein’s calculation was
premised on the assumption that defendant was in the elimination phase, without consideration
of other relevant factors and without additional breath tests, we find the probative value of his
testimony to be significantly diminished. See Armstrong, 267 P.3d at 783.
¶ 24 Conversely, the risk of unfair prejudice from Wetstein’s calculation was substantial.
Illinois courts have defined “unfair prejudice” as an “ ‘ “undue tendency to suggest decision on
an improper basis, commonly an emotional one, such as sympathy, hatred, contempt, or
horror.” ’ ” People v. Barnes, 2013 IL App (1st) 112873, ¶ 44 (quoting People v. Eyler, 133 Ill.
2d 173, 218 (1989), quoting Michael H. Graham, Cleary and Graham’s Handbook of Illinois
Evidence § 403.1 (4th ed. 1984)). In this case, we find the reasoning in Armstrong applicable.
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2014 IL App (2d) 120507
The introduction of Wetstein’s retrograde extrapolation calculation, when many necessary
factors were unknown and when only one breath test was administered, invited the jury to
convict her due to a reaction to a supposedly high BAC rather than proof beyond a reasonable
doubt that defendant was driving under the influence. See Armstrong, 267 P.3d at 781.
¶ 25 We emphasize that our holding is limited to the specific circumstances of this case, and
we recognize that retrograde extrapolation “has its place in proving that a defendant was driving
under the influence.” Id. at 783-84. In doing so, we further emphasize that we are not creating a
blueprint or a bright-line rule for the admissibility of retrograde extrapolation evidence. As the
court in Armstrong noted, not every factor must be known to construct a reliable extrapolation;
rather, the various factors must be balanced. Id. at 783. Whether the State produces a reliable
extrapolation will depend on the specific circumstances of each case.
¶ 26 We are also cognizant of the State’s concern that many of the factors necessary to
determine if a person was in the elimination phase will be difficult to obtain if that person
invokes his or her privilege against self-incrimination. Nonetheless, we believe that the State
could still reliably conclude that a defendant was in the elimination phase by conducting
additional breath or blood tests. As the court in Mata opined:
“If the State had more than one test, each test a reasonable length of time apart, and the
first test [was] conducted within a reasonable time from the time of the offense, an expert
could potentially create a reliable estimate of the defendant’s BAC with limited
knowledge of personal characteristics and behaviors.” Mata, 46 S.W.3d at 916.
¶ 27 In sum, because the State’s expert witness acknowledged that he was unaware of many of
the factors necessary to determine whether defendant was in the elimination phase, and because
the police conducted only one BAC test, we find the extrapolation calculation to be inherently
unreliable. In addition, because the extrapolation evidence invited the jury to convict defendant
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on the basis of a supposedly high BAC, the potential for prejudice from admitting that evidence
was high. Because the prejudicial effect of the extrapolation substantially outweighed the
probative value, the trial court abused its discretion in admitting the evidence. See generally
McKown, 236 Ill. 2d at 314 (noting that the admissibility of scientific evidence is subject to the
balancing of probative value and the risk of unfair prejudice). Further, given the conflicting
nature of the other testimony at trial, including that defendant passed some field sobriety tests
while failing others, the trial court’s admission of the extrapolation evidence was not harmless.
See id. at 311 (rejecting a harmless error argument).
¶ 28 Nonetheless, although we are reversing, we find that, after viewing the evidence in the
light most favorable to the State, there was sufficient evidence from which the jury could have
found defendant guilty of aggravated DUI beyond a reasonable doubt. See People v. Lopez, 229
Ill. 2d 322, 366-67 (2008) (noting that the relevant inquiry into whether double jeopardy
prohibits another trial is whether, after viewing the evidence in the light most favorable to the
State, including suppressed evidence, any rational trier of fact could have found the essential
elements of the crime beyond a reasonable doubt). The evidence in this case included the
improperly admitted extrapolation evidence, the field sobriety tests, and Drew’s opinion
testimony.
¶ 29 Finally, while we note that defendant has raised other issues on appeal, we decline to
review them. “As a general rule, a court of review will not decide moot or abstract questions or
render advisory opinions.” People v. Campa, 217 Ill. 2d 243, 269 (2005).
¶ 30 For the foregoing reasons, we reverse the judgment of the circuit court of Kane County
and remand for a new trial.
¶ 31 Reversed and remanded.
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