United States v. Kristen Smith , 701 F.3d 1002 ( 2012 )


Menu:
  •                        PUBLISHED
    UNITED STATES COURT OF APPEALS
    FOR THE FOURTH CIRCUIT
    UNITED STATES OF AMERICA,             
    Plaintiff-Appellee,
    v.                         No. 11-4336
    KRISTEN DEANNA SMITH,
    Defendant-Appellant.
    
    Appeal from the United States District Court
    for the District of Maryland, at Greenbelt.
    Roger W. Titus, District Judge.
    (8:10-cr-00069-RWT-1)
    Argued: September 21, 2012
    Decided: December 17, 2012
    Before DUNCAN, AGEE, and DIAZ, Circuit Judges.
    Affirmed by published opinion. Judge Diaz wrote the opinion,
    in which Judge Duncan and Judge Agee joined.
    COUNSEL
    ARGUED: William A. Mitchell, Jr., BRENNAN, SULLI-
    VAN & MCKENNA, LLP, Greenbelt, Maryland, for Appel-
    lant. Hollis Raphael Weisman, OFFICE OF THE UNITED
    STATES ATTORNEY, Greenbelt, Maryland, for Appellee.
    ON BRIEF: Timothy J. Sullivan, BRENNAN, SULLIVAN
    2                   UNITED STATES v. SMITH
    & MCKENNA, LLP, Greenbelt, Maryland, for Appellant.
    Rod J. Rosenstein, United States Attorney, Baltimore, Mary-
    land, for Appellee.
    OPINION
    DIAZ, Circuit Judge:
    Kristen Deanna Smith was convicted by a jury of involun-
    tary manslaughter during the commission of an unlawful act
    not amounting to a felony, in violation of 
    18 U.S.C. § 1112
    (a). The district court sentenced her to a term of fifty-
    one months’ imprisonment.
    Smith advances three arguments on appeal. First, she con-
    tends the district court erred by admitting expert testimony
    that she claims exceeded the scope of the government’s pre-
    trial disclosure. Second, Smith challenges the sufficiency of
    the government’s evidence, arguing that the district court
    erred when it denied her motion for judgment of acquittal pur-
    suant to Fed. R. Crim. P. 29. Finally, Smith contends the dis-
    trict court erred in rejecting one of her proposed jury
    instructions. We conclude that the district court committed no
    reversible error and that sufficient evidence supported the
    jury’s verdict. Accordingly, we affirm.
    I.
    On appeal from a criminal conviction, we view the evi-
    dence in the light most favorable to the government. United
    States v. Herder, 
    594 F.3d 352
    , 358 (4th Cir. 2010).
    A.
    At about 3:00 a.m. on October 31, 2009, Amber Howard
    was driving south from Maryland into the District of Colum-
    UNITED STATES v. SMITH                          3
    bia along the Baltimore-Washington Parkway, a federal area
    maintained by the National Park Service. As she approached
    D.C., she saw a car’s lights coming toward her from the
    northbound side of the highway. She watched that car drive
    over the median, flip several times, and crash into the high-
    way’s southbound-side embankment.
    Howard pulled over and dialed 911, then ran to check on
    the accident. She approached the car and heard a woman
    screaming for help. As Howard tried to indicate that help was
    on the way, the woman, appellant Kristen Smith, exited the
    wrecked vehicle through its rear passenger window and
    walked toward Howard. As Smith approached, Howard heard
    her say: "I never drink. I never drink. I didn’t want to go out.
    I never drink. I only had one drink." Howard also saw the arm
    of Smith’s passenger, Jabari Outz, hanging out the car win-
    dow.
    While waiting for the police to arrive, a distressed and dis-
    oriented Smith repeatedly wandered onto the highway, forc-
    ing Howard to pull her out of the road several times. Howard
    also smelled the odor of "white liquor" emanating from
    Smith. "White liquor," as Howard explained at trial, is alcohol
    such as vodka, gin, or tequila, and in Howard’s experience as
    a bartender, has a smell distinct from dark liquor or beer.
    United States Park Police Officer Gary Hatch arrived on
    the scene at about 3:30 a.m. and found Smith’s car on its side,
    leaning against a stone wall. By this time, Outz had been pro-
    nounced dead on the scene by emergency medical services.
    Officer Hatch, who had some experience as an accident
    reconstructionist, analyzed the scene and determined that
    Smith’s car had left the northbound roadway, flipped after
    crossing the median, and crashed into the stone wall.
    Smith was taken to Prince George’s County Hospital,
    where she submitted to a routine blood test.1 U.S. Park Police
    1
    Because the government was unable to establish the chain of custody
    of this blood sample, it did not attempt to introduce any evidence of its
    blood alcohol results.
    4                   UNITED STATES v. SMITH
    Officer David Lorde was dispatched to stay with Smith while
    she received treatment in the emergency room. He testified
    that Smith was writhing in bed and making unsolicited state-
    ments, three of which he recalled in particular: "Don’t ever
    drink and drive," "I just hope he’s okay," and "Lock me up
    and throw away the key."
    Some time later, U.S. Park Police Officer Ernest Patrick
    arrived at the emergency room to oversee a second blood
    draw, which was conducted at 5:47 a.m. The blood sample
    from this draw, which showed a blood alcohol content of .09
    grams per 100 milliliters, was furnished to Lucas Zarwell, the
    Deputy Chief Toxicologist at the Office of the Chief Medical
    Examiner in Washington, D.C.
    B.
    The government charged Smith in a single-count indict-
    ment for homicide during the commission of an unlawful act
    not amounting to a felony, in violation of 
    18 U.S.C. § 1112
    (a). The underlying unlawful act was an alleged viola-
    tion of 
    36 C.F.R. § 4.23
    (a)(2), which provides that
    "[o]perating or being in actual physical control of a motor
    vehicle is prohibited while . . . [t]he alcohol concentration in
    the operator’s blood or breath is 0.08 grams or more of alco-
    hol per 100 milliliters of blood[.]" Notably, the government
    chose not to charge Smith with a violation of 
    36 C.F.R. § 4.23
    (a)(1), which prohibits operating a motor vehicle while
    "[u]nder the influence of alcohol . . . to a degree that renders
    the operator incapable of safe operation[.]" Unlike the "per
    se" § 4.23(a)(2) violation, § 4.23(a)(1) does not require the
    government to prove the defendant’s blood alcohol level.
    Deputy Chief Toxicologist Zarwell testified as an expert
    witness on the results of the 5:47 a.m. blood sample, stating
    that it contained .09 grams of alcohol per 100 milliliters of
    blood. Over the defense’s objection, Zarwell also gave gener-
    alized testimony about how the human body metabolizes alco-
    UNITED STATES v. SMITH                    5
    hol, including the average duration of alcohol absorption and
    rate of elimination. He indicated that typically people con-
    tinue to absorb alcohol for "about 30 minutes" after they stop
    drinking and that females eliminate alcohol at an average rate
    of about .017 grams per 100 milliliters per hour. J.A. 120-21.
    Prior to cross-examination, Smith renewed her objection to
    Zarwell’s statements on alcohol metabolization, moving to
    strike this line of testimony on the ground that it exceeded the
    scope of the pretrial notice provided by the government.
    Pointing to a series of letters exchanged between counsel
    before trial, the defense charged that the government had rep-
    resented that Zarwell’s testimony would be limited to the
    results of Smith’s 5:47 a.m. blood test. The defense argued
    that without explicit notice that Zarwell would be testifying
    about metabolization rates more generally, it was unprepared
    to effectively cross-examine Zarwell and unable to realisti-
    cally procure a rebuttal witness. Smith did not move for a
    continuance or otherwise indicate that she wanted time to pro-
    cure her own expert witness regarding blood alcohol absorp-
    tion rates, although the court indicated that she could call her
    own witness in response to Zarwell’s broadened testimony.
    The district court denied the motion to strike, holding that
    the government’s disclosures were sufficient. Zarwell’s
    generic testimony, the court explained, was within his area of
    expertise and served as necessary background to his testimony
    on Smith’s blood test result. Nor did the court find the admis-
    sion of Zarwell’s testimony to be unduly prejudicial, since
    Smith had the opportunity to cross-examine him and to find
    her own toxicology expert.
    The district court also rejected the defense’s alternative
    contention that Zarwell’s testimony on generic human alcohol
    metabolization was irrelevant as to Smith’s blood alcohol
    content at the time of the accident. Even though Zarwell had
    not offered an opinion as to Smith’s blood alcohol content at
    3:00 a.m., the court reasoned that the jury was not prohibited
    6                   UNITED STATES v. SMITH
    from making inferences on that issue based on Zarwell’s
    generic metabolization testimony and the results of the 5:47
    a.m. test.
    During cross-examination, Zarwell confirmed that his
    blood alcohol analysis showed the quantity of alcohol in
    Smith’s blood only at the time of the 5:47 a.m. test, not
    beforehand. He also conceded, notwithstanding his earlier tes-
    timony about typical alcohol absorption and elimination rates,
    that those rates are highly variable among individuals. Zar-
    well stated that although he would have been able to conduct
    an individualized analysis of Smith’s absorption and elimina-
    tion rates, he had not done so. Zarwell also confirmed that he
    had not performed a retrograde extrapolation of Smith’s blood
    alcohol level at the time of the crash and did not offer any
    opinion about her blood alcohol level at that time.
    At the close of the government’s case in chief, Smith
    moved for a judgment of acquittal under Fed. R. Crim. P. 29,
    arguing that the evidence produced by the government was
    insufficient to show her blood alcohol level exceeded .08 at
    the time of the accident, almost three hours before the blood
    test. The district court denied the motion, concluding that
    based upon the 5:47 a.m. blood test result, the evidence of
    Smith’s erratic driving and behavior, and the statements she
    made at the hospital, a rational jury could reasonably infer
    that she had violated § 4.23(a)(2). Smith offered no evidence
    and renewed her motion for judgment of acquittal, which the
    district court again denied.
    At the charge conference, Smith requested several supple-
    mental jury instructions, one of which proposed to instruct the
    jury, in relevant part, as follows:
    As you heard, the rates of alcohol absorption and
    elimination can vary between persons. Therefore, the
    practice of extrapolating a person’s blood alcohol
    level at the time of driving from a test of a blood
    UNITED STATES v. SMITH                    7
    sample taken at a later time requires careful consid-
    eration of many factors . . . . I instruct you that you
    should not attempt to extrapolate the blood alcohol
    of the accused at the time of driving from the result
    of a blood test from samples taken at a later time
    unless sufficient evidence has been presented to you
    with regard to the aforementioned factors . . . . You
    may not infer from the test of defendant’s blood
    samples taken at 5:47 a.m. on October 31, 2009, in
    this case—without more, as I have described
    above—what defendant’s blood alcohol content at
    the time of driving around 3:00 a.m. might have
    been.
    S.J.A. 3; J.A. 141.
    The district court rejected this instruction. It explained that
    the jury already knew that there was no piece of evidence,
    standing alone, showing that Smith’s blood alcohol content
    exceeded .08 at the time of the crash—an element the existing
    jury instructions already established was essential to the
    crime. But because there were other facts in the record from
    which the jury might reasonably infer the § 4.23(a)(2) viola-
    tion, the court allowed the jury to draw those inferences.
    The jury returned a guilty verdict on the sole count of the
    indictment. Prior to sentencing, Smith renewed her motion for
    judgment of acquittal and moved for a new trial. The district
    court denied both motions and imposed its sentence. This
    appeal followed.
    II.
    The issues before us are (1) whether the district court erred
    in permitting the government’s toxicology expert to testify
    about generic alcohol metabolization rates; (2) whether Smith
    was entitled to a judgment of acquittal due to insufficient evi-
    dence; and (3) whether the district court erred in refusing to
    8                        UNITED STATES v. SMITH
    give Smith’s requested jury instruction concerning blood
    alcohol level extrapolation. We consider each issue in turn.
    A.
    Smith contends the district court erred in permitting the
    government’s toxicology expert to testify about generic alco-
    hol metabolization rates. We review the district court’s evi-
    dentiary rulings for abuse of discretion, United States v.
    Basham, 
    561 F.3d 302
    , 325 (4th Cir. 2009), and generally will
    not reverse absent a showing of prejudice, United States v.
    Durham, 
    319 F.2d 590
    , 592 (4th Cir. 1963).
    Smith argues that she was unfairly surprised by toxicologist
    Lucas Zarwell’s testimony regarding average human alcohol
    metabolization rates because this testimony exceeded the
    scope of the pretrial notice provided by the government pur-
    suant to Fed. R. Crim. P. 16. As she did at trial, Smith points
    to the series of letters exchanged between counsel during dis-
    covery that comprised the parties’ Rule 16 communications.
    J.A. 351-61. The government’s initial written disclosure
    included Zarwell’s curriculum vitae and named him as the
    likely toxicology expert. In response, Smith’s counsel wrote:
    "It is assumed from your discovery response that the expert
    evidence would be limited to testimony . . . that [Smith’s 5:47
    a.m.] blood sample revealed an ethanol level of .09%." J.A.
    359. The government’s reply confirmed that Smith’s charac-
    terization was "correct as to the toxicology expert testimo-
    ny[.]" J.A. 361. Smith argues that since Zarwell’s testimony
    was not confined to the results of the blood test, as the letters
    suggested it would be, the district court abused its discretion
    by admitting it. As a result, Smith claims she was unable to
    effectively cross-examine Zarwell on the intricacies of
    "relation-back" science2 or prepare her own expert to rebut
    Zarwell’s testimony.
    2
    "Relation-back" science attempts to extrapolate—or relate back—the
    results of a blood alcohol test administered after a person’s arrest to his
    or her blood alcohol level at the time of operation of the vehicle. See
    Ransford v. District of Columbia, 
    583 A.2d 186
    , 186 (D.C. 1990). As both
    parties have noted, the reliability of relation-back science is up for debate.
    Appellee’s Br. at 29-30; J.A. 114.
    UNITED STATES v. SMITH                             9
    The government echoes the district court’s justification for
    admitting the evidence, arguing that Zarwell gave no testi-
    mony about Smith’s personal alcohol elimination rate and that
    Zarwell’s testimony concerning typical human alcohol meta-
    bolization was general background information within the
    scope of both the notice and his expertise. It notes that Smith
    never objected to Zarwell’s qualifications as a toxicology
    expert and that, having sat down with Zarwell before trial for
    an in-person interview, Smith’s counsel had ample opportu-
    nity to prepare for cross-examination. Finally, the government
    asserts that even assuming error, Smith has failed to demon-
    strate how she suffered any prejudice as a result of the testi-
    mony or the wording of the government’s pretrial disclosure.
    Federal Rule of Criminal Procedure 16(a)(1)(G) requires
    the government to give, at the defendant’s request, a written
    summary of any expert testimony that it intends to use during
    its case-in-chief at trial. This summary "must describe the wit-
    ness’s opinions, the bases and reasons for those opinions, and
    the witness’s qualifications." Fed. R. Crim. P. 16(a)(1)(G). As
    the rule’s Advisory Committee Notes explain, Rule
    16(a)(1)(G) "is intended to minimize surprise that often
    results from unexpected expert testimony . . . and to provide
    the opponent with a fair opportunity to test the merit of the
    expert’s testimony through focused cross-examination." Fed.
    R. Crim. P. 16(a)(1)(G) Advisory Comm. Note to the 1993
    amendment.
    On the one hand, we do not fault Smith for taking issue
    with the government’s less than fulsome pretrial summary of
    Zarwell’s planned expert testimony.3 On the other hand, con-
    3
    To be fair, the government’s Rule 16 disclosure should be read in con-
    text; it was drafted in part to inform Smith that it would not be introducing
    the results of the earlier blood alcohol test, but would only be introducing
    the results of the second test. At trial, the government contended that one
    reason it sought to elicit Zarwell’s generic testimony regarding blood alco-
    hol absorption was Smith’s sole defense—articulated during opening
    10                     UNITED STATES v. SMITH
    sistent with the government’s Rule 16 disclosure, Zarwell
    declined to offer any opinion on Smith’s personal metaboliza-
    tion rate, and did not attempt to extrapolate what her blood
    alcohol content might have been at 3:00 a.m. And although
    full disclosure by the government would have been more in
    keeping with the spirit of Rule 16, we think it fair to charac-
    terize Zarwell’s testimony on typical human alcohol absorp-
    tion and elimination rates as generic background information
    that fell within the scope of Zarwell’s expertise.
    In any event, we need not decide whether the district court
    erred in concluding that the Government did not violate Rule
    16(a)(1)(G), because any error was harmless. In addition to
    showing the district court’s error, a defendant seeking reversal
    under Rule 16(a)(1)(G) must also "demonstrate prejudice
    resulting from the district court’s decision to admit the con-
    tested testimony." United States v. Buchanan, 
    604 F.3d 517
    ,
    526 (8th Cir. 2010); see also United States v. Charley, 
    189 F.3d 1251
    , 1261-62 (10th Cir. 1999) (affirming a district court
    decision despite a Rule 16 violation, due to absence of preju-
    dice to defendant).
    Smith fails to make that showing here. Although Smith
    claims that the government’s incomplete Rule 16 disclosure
    prevented her from effectively cross-examining Zarwell on
    the intricacies of relation-back science, Zarwell never offered
    any such evidence. Further, Smith interviewed Zarwell prior
    to the trial, and extensively cross-examined him at trial
    regarding the numerous factors that determine an individual’s
    statements—that the toxicology report only reflected Smith’s blood alco-
    hol level at the time it was taken and was irrelevant to her blood alcohol
    level at the time of the accident. See United States v. Basic Constr. Co.,
    
    711 F.2d 570
    , 574 (4th Cir. 1984) (observing that while the practice of
    permitting evidence in the government’s case-in-chief based on arguments
    made during a defendant’s opening statement should be "discouraged," it
    may be harmless where the defendant "followed through on its articulated
    defense").
    UNITED STATES v. SMITH                       11
    blood alcohol absorption rate, the nuances of his generalized
    direct testimony, and whether it was possible that a person’s
    blood alcohol level would continue to increase for a few hours
    after consumption.4 And to the extent Smith disagreed with
    Zarwell’s testimony regarding general metabolization rates,
    the district court gave her ample opportunity to call her own
    rebuttal expert. Smith simply chose not to pursue that avenue
    or ask for a continuance to consider it.
    For these reasons, we conclude that the district court did
    not commit reversible error in permitting Zarwell’s expert tes-
    timony.
    B.
    We next consider Smith’s argument that she was entitled to
    a judgment of acquittal because the government offered insuf-
    ficient evidence to support her conviction. We review de novo
    the district court’s decision to deny a defendant’s Rule 29
    motion for judgment of acquittal. United States v. Smith, 
    451 F.3d 209
    , 216 (4th Cir. 2006). On an appeal challenging the
    sufficiency of evidence, we assess the evidence in the light
    most favorable to the government, and the jury’s verdict must
    stand unless we determine that no rational trier of fact could
    have found the essential elements of the crime beyond a rea-
    sonable doubt. United States v. Young, 
    609 F.3d 348
    , 355 (4th
    Cir. 2010).
    Smith concedes that the government presented evidence
    that she was under the influence of alcohol at the time of the
    accident. She also concedes that the government’s evidence
    established that her blood contained .09 grams of alcohol per
    100 milliliters at 5:47 a.m., nearly three hours after the crash.
    Smith contends, however, that the government did not offer
    sufficient evidence upon which a rational finder of fact could
    4
    Indeed, some of the testimony Smith elicited from Zarwell on cross-
    examination was favorable to her case.
    12                   UNITED STATES v. SMITH
    have determined beyond a reasonable doubt that, at the time
    she was operating her vehicle, her blood alcohol concentra-
    tion was .08 percent or more, as a 
    36 C.F.R. § 4.23
    (a)(2) "per
    se" violation requires. Absent such direct evidence, Smith
    insists, she was entitled to a judgment of acquittal.
    The government responds that its evidence was sufficient
    to support the conviction. It argues that the fact that Smith had
    a blood alcohol content exceeding .08 percent within a rea-
    sonable period of the time after driving sufficed to show a
    violation of the § 4.23(a)(2) "per se" offense, without any
    need for relation-back evidence, which it argues is unreliable
    and impractical to obtain. While acknowledging that
    § 4.23(a)(2) does require a showing that a defendant’s blood
    alcohol content exceeded .08 at the time of driving, the gov-
    ernment suggests it would be absurd to hold that the "per se"
    offense requires the government to prove precisely the blood
    alcohol level at the time of driving. Instead, the government
    asks us to hold that a blood alcohol test taken within a reason-
    able time after driving satisfies the "per se" statute. Finally,
    the government points to other evidence supporting the jury’s
    finding that Smith violated § 4.23(a)(2): evidence that Smith
    was driving recklessly, testimony that she was behaving errat-
    ically and that she smelled of "white liquor," and statements
    she made at the scene of the accident and at the hospital about
    her own drinking and driving.
    Section 4.23(a)(2) provides that "[o]perating or being in
    actual physical control of a motor vehicle is prohibited while
    . . . [t]he alcohol concentration in the operator’s blood or
    breath is 0.08 grams or more of alcohol per 100 milliliters of
    blood[.]" Unlike some comparable state statutes, § 4.23(a)(2)
    sets no explicit time limit for the taking of a blood alcohol test
    that may be used at trial to show a defendant’s alcohol con-
    centration. Compare 
    36 C.F.R. § 4.23
    (a)(2), with Va. Code.
    Ann. § 18.2-268.2A (setting a three-hour limit between "the
    offense" and the taking of the sample), and 
    Md. Code Ann., Cts. & Jud. Proc. § 10-303
    (a)(2) (setting a two-hour limit
    UNITED STATES v. SMITH                   13
    after the person has been "apprehended"). Section 4.23(a)(2)
    is also silent as to the regulation’s proof requirements, and we
    have found no published authority from our sister circuits on
    this question, which has become the subject of some debate
    among other lower courts.
    Some courts have interpreted § 4.23(a)(2) to mean that the
    government must directly prove a defendant’s blood alcohol
    content at the time he or she was driving, often through
    relation-back testimony. For example, the United States Dis-
    trict Court for the District of Nevada has twice refused to find
    later-administered breath tests sufficient to support a
    § 4.23(a)(2) conviction. See United States v. French, No.
    2:08-MJ-726-GWF, 
    2010 WL 1633456
     (D. Nev. Apr. 10,
    2010) (unpublished); United States v. Stout, No.
    2:09–MJ–00146–GWF, 
    2009 WL 5217047
     (D. Nev. Dec. 28,
    2009) (unpublished). As the Stout court reasoned:
    Unlike some state DUI laws, 
    36 C.F.R. § 4.23
    (a)(2)
    does not make it unlawful to have a blood alcohol
    level above the legal limit within a specified time
    after operating a motor vehicle. Nor does it contain
    a presumption regarding the person’s blood alcohol
    at the time he was operating or in physical control of
    a vehicle based on subsequently obtained breath or
    blood test results. Because there is no presumption
    based on the test results, the Government is required
    to prove that a defendant’s blood alcohol content
    was above the legal limit at the time of operating the
    vehicle and not merely at the time the breath or
    blood sample was taken.
    
    2010 WL 1633456
    , at *6. Courts interpreting § 4.23(a)(2) to
    require relation-back evidence have also noted the availability
    to the government of proceeding under § 4.23(a)(1), which
    has no blood alcohol content requirement. See United States
    v. Wight, 
    884 F. Supp. 400
    , 402 (D. Colo. 1995). By choosing
    14                  UNITED STATES v. SMITH
    to proceed on the "per se" violation, the Wight court
    explained, the government
    had an obligation under the regulation to establish
    the alcohol concentration at the time of driving or
    actual physical control. The test result at 8:27 a.m.
    was insufficient, in and of itself, to establish what
    Defendant’s concentration was at 6:15 a.m., or even
    at 7:00 a.m. Once [the government] chose to proceed
    on the "per se" violation, it had to present qualified
    evidence that "related back" the test results to the
    time of driving or actual physical control.
    
    Id. at 403
    .
    Meanwhile, other courts dealing with similar "per se" stat-
    utes have held that relation-back testimony is unnecessary to
    prove the offense. And where, as here, those statutes impose
    no time limit on the blood alcohol test, courts have also regu-
    larly found that violations may be established as long as the
    government produces evidence of blood alcohol levels within
    a reasonable time after driving. See, e.g., Commonwealth v.
    Colturi, 
    864 N.E.2d 498
    , 500 (Mass. 2007); State v. McGo-
    wan, 
    139 P.3d 841
    , 844 (Mont. 2006); Ransford, 
    583 A.2d at 190
    .
    For example, in a case cited by the district court below, the
    Montana Supreme Court concluded that a comparable state
    "per se" statute could not be read literally "to require law
    enforcement officers to determine a person’s alcohol concen-
    tration while driving . . . , as it would be impossible for an
    officer to administer a test while the suspect was driving."
    McGowan, 
    139 P.3d at 844
    . Nor, McGowan concluded,
    should the government be required to meet what it character-
    ized as the "impossible burden" of presenting relation-back
    evidence. 
    Id. at 845
    . Such extrapolation, the court explained,
    would require difficult-to-obtain evidence falling within a
    defendant’s constitutional right to remain silent, such as when
    UNITED STATES v. SMITH                         15
    and in what amounts the defendant consumed alcohol, and
    whether the defendant had recently consumed any food. 
    Id.
    Another court, reaching the same conclusion, pointed out that
    even if the prosecution could obtain this information, "conclu-
    sive evidence of the blood alcohol content at the time of driv-
    ing could still not be offered to the jury . . . because the rate
    of absorption of alcohol varies between individuals." Rans-
    ford, 
    583 A.2d at 190
    . These courts have concluded that legis-
    latures could not have intended to impose such evidentiary
    hurdles on the prosecution. Id.; McGowan, 
    139 P.3d at
    844-
    45.
    We need not decide whether, on its own, a blood alcohol
    test taken within a "reasonable time" after driving can satisfy
    the proof requirement of § 4.23(a)(2)’s "per se" offense.
    Rather, it is enough for us to say that the government may, in
    some circumstances, establish a "per se" violation without
    direct evidence of the defendant’s blood alcohol content while
    actually driving and without introduction of relation-back evi-
    dence.
    In the instant case, we are satisfied that a rational finder of
    fact could have determined beyond a reasonable doubt that
    Smith violated the "per se" regulation. Even if Smith is cor-
    rect that, standing alone, her 5:47 a.m. blood alcohol result
    was insufficient to establish the violation, this evidence did
    not actually stand alone. The government presented myriad
    other evidence supporting the jury’s conclusion that Smith’s
    blood alcohol level was over the legal limit while she was
    driving. Most notably, Zarwell’s unrebutted testimony about
    typical alcohol absorption durations and elimination rates
    established that it was extremely unlikely that Smith could
    have registered a .09 percent blood alcohol content at 5:47
    a.m. without having exceeded the .08 percent threshold at the
    time of the crash nearly three hours earlier.5 Even accounting
    5
    As the district court noted and as the government told the jury in its
    closing argument, there was no evidence that Smith had consumed any
    16                     UNITED STATES v. SMITH
    for the wide range of individual alcohol metabolization rates
    to which Zarwell attested, and even assuming that Smith
    absorbs and eliminates alcohol much more slowly than the
    average woman, a rational juror could still have concluded
    beyond a reasonable doubt that a "per se" violation had
    occurred.
    This is particularly true, as the district court noted, given
    the abundant other indicia of Smith’s guilt. The evidence
    established that Smith was driving erratically and that she
    flipped her car over the highway’s median strip. Howard testi-
    fied that Smith was behaving erratically, wandering into the
    road, and that she smelled strongly of "white liquor." Smith
    also made statements to two witnesses about her own drinking
    and driving. To be sure, none of this evidence points defini-
    tively to Smith’s precise blood alcohol level at the time of the
    accident. When coupled, however, with the result of the 5:47
    a.m. blood alcohol test and Zarwell’s generic metabolization
    testimony, this evidence could lead a rational juror to deter-
    mine beyond a reasonable doubt that Smith had violated the
    regulation’s .08 threshold.
    Accordingly, we conclude that Smith was not entitled to a
    judgment of acquittal.
    C.
    Finally, we address Smith’s contention that the district
    court erred in refusing to give her requested jury instruction
    concerning blood alcohol level extrapolation. We review a
    district court’s decision to give or refuse to give a jury
    alcohol between the time of the accident and the time her blood was
    drawn. The jury could therefore reasonably infer that any alcohol that
    appeared in her 5:47 a.m. blood sample had been in her system at the time
    she was operating the vehicle, and that apart from the absorption of
    previously-consumed alcohol that Zarwell had described, there was no
    reason why Smith’s blood alcohol concentration would have increased
    during that interim period.
    UNITED STATES v. SMITH                     17
    instruction for abuse of discretion, and reverse only when the
    rejected instruction "(1) was correct; (2) was not substantially
    covered by the court’s charge to the jury; and (3) dealt with
    some point in the trial so important, that failure to give the
    requested instruction seriously impaired the defendant’s abil-
    ity to conduct his defense." United States v. Passaro, 
    577 F.3d 207
    , 221 (4th Cir. 2009) (internal quotation marks omit-
    ted). "Moreover, we do not view a single instruction in isola-
    tion; rather we consider whether taken as a whole and in the
    context of the entire charge, the instructions accurately and
    fairly state the controlling law." 
    Id.
     (internal quotation marks
    omitted).
    Smith contends that the district court erred in refusing to
    instruct the jury that it could not infer her guilt from the result
    of her 5:47 a.m. blood test, "without more." Absent this
    instruction, Smith argues, the jury was left to engage in con-
    jecture and speculation about the results of the blood sample
    and its evidentiary value to the elements of the crime charged.
    The government responds that the court’s instructions were
    complete and correct, and that they sufficiently explained to
    the jury that it could decide whether Smith had a .08 percent
    or more blood alcohol content at the time of the crash, based
    on all the evidence it heard.
    We conclude that the district court did not abuse its discre-
    tion in refusing to give Smith’s proposed instruction, because
    that instruction was not necessarily correct and, in any event,
    was "substantially covered by the court’s charge to the jury."
    Passaro, 
    577 F.3d at 221
    . As the district court noted, Smith’s
    proposed instruction that the jury could not infer guilt from
    the 5:47 a.m. blood test, "without more," could easily have led
    to confusion about what other evidence the jury was allowed
    to consider. By the same token, the proposed instruction also
    improperly implied that, beyond the 5:47 a.m. blood test,
    there was no other evidence supporting an inference of guilt.
    The district court’s instructions set forth the elements of the
    crime and made clear the government’s burden of proving
    18                   UNITED STATES v. SMITH
    beyond a reasonable doubt that at the time of the accident
    Smith’s blood alcohol content was .08 or higher. Even as it
    recognized that there was no direct evidence that Smith’s
    blood alcohol content exceeded the .08 threshold while she
    was driving, the district court rightly concluded that there
    were facts in the record from which the jury might reasonably
    infer the violation and instructed the jury that it was free to
    either make that inference or not. Ultimately, when "[t]aken
    as a whole and in the context of the entire charge, the instruc-
    tions accurately and fairly state[d] the controlling law." Pas-
    saro, 
    577 F.3d at 221
    . As a result, the district court did not
    abuse its discretion in denying Smith’s proposed instruction.
    III.
    In sum, the district court did not abuse its discretion in
    admitting the toxicologist’s generic testimony on alcohol
    metabolization. Nor was Smith entitled to judgment of acquit-
    tal, because the government’s evidence was sufficient to sup-
    port the jury’s verdict. Finally, the district court did not abuse
    its discretion in denying Smith’s proposed jury instruction.
    Accordingly, we affirm the judgment of the district court.
    AFFIRMED