Robinson v. Washington Metropolitan Area Transit Authority ( 2014 )


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  • United States Court of Appeals
    FOR THE DISTRICT OF COLUMBIA CIRCUIT
    Argued September 12, 2014           Decided December 19, 2014
    No. 13-7077
    DARLENE C. ROBINSON,
    APPELLANT
    v.
    WASHINGTON METROPOLITAN AREA TRANSIT AUTHORITY,
    APPELLEE
    Appeal from the United States District Court
    for the District of Columbia
    (No. 1:11-cv-00723)
    Charles C. Parsons argued the cause and filed the briefs for
    appellant.
    Kathleen A. Carey argued the cause and filed the briefs for
    appellees. Mark F. Sullivan entered an appearance.
    Before: GARLAND, Chief Judge, SRINIVASAN, Circuit
    Judge, and SENTELLE, Senior Circuit Judge.
    Opinion for the Court filed by Chief Judge GARLAND.
    2
    GARLAND, Chief Judge: A bus driver, one Mr. Bumpass,
    hits the brakes as he approaches a stop sign. The plaintiff, a
    passenger on the bus, falls backward and breaks her leg. The
    question on appeal is whether, in light of the evidence presented
    at trial, a reasonable jury could find the bus company liable for
    the plaintiff’s injury. Applying the common law of the District
    of Columbia, we affirm the district court’s conclusion that a
    reasonable jury could not.
    I
    On the morning of April 16, 2008, Darlene Robinson
    boarded a Washington Metropolitan Area Transit Authority
    (WMATA) bus at the Gallatin and 11th Street stop in Northeast
    Washington, D.C. She paid her fare and proceeded past bus
    driver Ronald Bumpass. Robinson continued down the aisle,
    gripping the seat-back handrails as she went. Bumpass closed
    the doors and began driving away from the stop. Shortly
    thereafter, Bumpass hit the brakes as he approached a stop sign
    on Gallatin Street. As the bus decelerated, Robinson -- who was
    still standing, facing the back of the bus -- lost her grip on a
    handrail, fell in a twisting motion, “landed on [her] . . .
    backside,” and broke her left leg. J.A. 514 (Robinson
    Testimony).
    Robinson sued WMATA, alleging that Bumpass’ negligent
    operation of the bus caused her injury and that WMATA was
    responsible.1 At trial, Robinson sought to prove Bumpass’
    negligence on two theories. First, she sought to show that he
    1
    Robinson’s complaint named WMATA and “Bus Driver John
    Doe” as defendants. J.A. 37. Although Robinson reserved the right
    to amend her complaint when she learned the driver’s identity, she did
    not do so. The parties have proceeded on the understanding that
    WMATA is the sole defendant, and so do we.
    3
    violated WMATA’s standard operating procedures (SOPs).
    Second, she sought to show that the “jerk” caused by Bumpass’
    application of the brakes was of such extraordinary force that
    his negligence could be inferred.
    In support of her claim that Bumpass was negligent because
    he violated WMATA’s SOPs, Robinson presented the expert
    testimony of Dr. Carl Berkowitz, a public transportation safety
    engineer. Dr. Berkowitz testified that the National Academy of
    Sciences and the U.S. Department of Transportation fund
    research studies to address transportation safety issues, and that
    the results and recommendations from those studies “emanate[]”
    and “filter[] down” to “all the major transit agencies.” J.A. 270-
    71. According to Berkowitz, those results and recommendations
    have led to nationally agreed-upon safety standards that all
    major cities in the United States, including the District of
    Columbia, have implemented.
    Dr. Berkowitz then identified two WMATA SOPs relevant
    to this case, and stated that each reflected the national standard
    of care for city bus travel. First, a WMATA bus driver is
    required to check his or her rearview mirror before departing
    from a stop to confirm that all passengers are “secure” and
    “prepared for vehicle movement.” J.A. 938, 941. Second, a
    WMATA bus driver is instructed to start the bus “gradually” and
    stop the bus “smoothly.” J.A. 942-43.
    Counsel for WMATA asked Dr. Berkowitz where and when
    these national standards for safe bus travel were articulated.
    Berkowitz replied that they were “developed from research,
    which actually dates back to Hammurabi -- the Hammurabi
    Code -- I guess [that] would be 3,500 years ago.” J.A. 458. He
    also said that the “first major research in this area[] was in the
    book of Deuteronomy.” 
    Id. 4 To
    establish that Bumpass violated the SOPs identified by
    Dr. Berkowitz, Robinson called Bumpass himself to the stand.
    Bumpass admitted that he did not check his mirror before
    leaving the stop that morning. He knew there were several open
    seats up front, he said, and he assumed Robinson had sat down
    by the time he closed the doors and started driving. J.A. 667-68.
    In support of her alternative theory -- that Bumpass’
    negligence was shown by the fact that his braking had caused
    the bus to jerk with extraordinary force -- Robinson took the
    stand to testify that the bus was going “fast, faster than normal
    buses,” J.A. 513, and that it “was jerking and then [there] was an
    abrupt stop,” J.A. 528. The abrupt stop, she testified, caused her
    to lose her grip on the handrail and fall. J.A. 528-29.
    Robinson also presented the expert testimony of Dr. Jamie
    Williams, a biomedical engineer, to explain how the force of the
    bus’ movements caused her to lose her grip on the handrail and
    fall down. Dr. Williams testified that a torsional force on
    Robinson’s left lower leg, brought about by the deceleration of
    the bus, caused her leg to break. Williams estimated that, based
    on the maximum grip strength of a woman of similar age and
    weight as Robinson, the “deceleration that would have
    destabilized her” would have been roughly “.38 times gravity.”
    J.A. 207. When asked on cross-examination if she had any
    information relating to the actual strength of Robinson’s grip
    that day, Dr. Williams acknowledged that she did not. She
    testified that her conclusions were premised on the assumption
    that Robinson had been holding onto the handrail as tightly as
    she possibly could. J.A. 227-28.
    At the close of Robinson’s case and again at the conclusion
    of all of the evidence, WMATA moved for judgment as a matter
    of law under Federal Rule of Civil Procedure 50(a). The district
    court reserved ruling on those motions and submitted the case to
    5
    the jury, which returned a verdict for Robinson and awarded her
    $404,713.28 in damages. Thereafter, the court granted
    WMATA’s renewed motion for judgment as a matter of law
    under Rule 50(b). Robinson v. WMATA, 
    941 F. Supp. 2d
    . 61
    (D.D.C. 2013).
    In granting judgment as a matter of law in favor of
    WMATA, the court rejected Robinson’s effort to prove
    negligence through the violation of WMATA’s standard
    operating procedures. The court concluded that Dr. Berkowitz
    had failed to show that either of the two SOPs reflected national
    standards of care; that there was no evidence of “a causal
    connection between the driver’s failure to check the internal
    center mirror and [Robinson’s] injury,” 
    id. at 69
    n.5; and that the
    “start gradually and stop smoothly” SOP could not serve as a
    negligence standard because to treat it as such “would be
    inconsistent with District of Columbia law,” 
    id. at 71.
    The court
    also rejected Robinson’s theory that Bumpass’ negligence could
    be inferred from the bus’ jerk, concluding that the evidence was
    insufficient to show that the jerk was of an extraordinary nature.
    Robinson filed a timely appeal, and that appeal is now
    before us.
    II
    We must affirm a Rule 50(b) judgment as a matter of law
    “if, after viewing the evidence in the light most favorable to the
    non-moving party and drawing all reasonable inferences, it is
    clear that a reasonable jury could only have found for the
    moving party.” Johnson v. WMATA, No. 90-7027, 
    1991 WL 214174
    , at *2 (D.C. Cir. 1991); see Conseil Alain Aboudaram,
    S.A. v. de Groote, 
    460 F.3d 46
    , 50 (D.C. Cir. 2006). Federal
    jurisdiction over this lawsuit arises under the WMATA
    6
    Compact. See D.C. Code § 9-1107.01(81).2 The Compact
    provides that WMATA shall be liable for the torts of its
    employees “in accordance with the law of the applicable
    signatory,” 
    id. § 9-1107.01(80),
    which in this case is the District
    of Columbia.3 The tort law of the District of Columbia therefore
    controls our disposition, Briggs v. WMATA, 
    481 F.3d 839
    , 843
    (D.C. Cir. 2007), and we must aim “to achieve the same
    outcome [that] would result if the District of Columbia Court of
    Appeals considered this case,” 
    id. (quoting Novak
    v. Capital
    Mgmt. & Dev. Corp., 
    452 F.3d 902
    , 907 (D.C. Cir. 2006)).
    In Johnson v. WMATA, we suggested that there are (at least)
    two theories under which a plaintiff may recover in a bus
    negligence case against WMATA. 
    1991 WL 214174
    , at *1.
    First, a plaintiff may present direct evidence of negligence. For
    example, evidence that a bus driver let himself be distracted
    while driving can be sufficient to recover. See Sibert-Dean v.
    WMATA, 
    721 F.3d 699
    , 701 (D.C. Cir. 2013) (affirming a
    finding of negligence where the driver turned to look at teenage
    girls). Evidence that a driver violated an applicable standard of
    care can likewise be sufficient. See WMATA v. O’Neill, 
    633 A.2d 834
    , 841 (D.C. 1993). Second, a plaintiff may offer
    circumstantial evidence of negligence by showing that the driver
    caused a jerk “so violent or extraordinary that it could not have
    been consistent with safe operation of the bus.” Johnson, 1991
    2
    The Compact -- an interstate agreement among the District of
    Columbia, Maryland, and Virginia -- created WMATA. See Pub. L.
    No. 89-774, 80 Stat. 1324 (1966) (codified as amended at D.C. Code
    § 9-1107.01 et seq.). Section 81 of the Compact provides that federal
    district courts shall have original jurisdiction, concurrent with the state
    courts of the three signatories, “of all actions brought by or against”
    WMATA. D.C. Code § 9-1107.01(81).
    3
    WMATA does not dispute that it is liable for Robinson’s injury
    if Bumpass was negligent and if that negligence caused the injury.
    
    7 WL 214174
    , at *2 (citing Boyko v. WMATA, 
    468 A.2d 582
    , 584
    (D.C. 1983)).
    The question on this appeal is whether Robinson presented
    sufficient evidence for a reasonable jury to find negligence
    under either theory. We address the direct evidence theory in
    Part III and the circumstantial evidence theory in Part IV.
    III
    Under District of Columbia law, a plaintiff seeking to prove
    her case through direct evidence of negligence has the burden of
    establishing three elements: (1) “the applicable standard of
    care”; (2) “a deviation from that standard by the defendant”; and
    (3) “a causal relationship” between the deviation and the injury
    she suffered. Varner v. District of Columbia, 
    891 A.2d 260
    , 265
    (D.C. 2006). To prove her case on this theory, Robinson argued
    that WMATA’s check-your-mirror and “start gradually, stop
    smoothly” SOPs constituted applicable standards of care; that
    Bumpass deviated from those standards; and that her injury was
    the consequence of those deviations. On appeal, she challenges
    the district court’s conclusion that she failed to establish that
    either of the SOPs constituted an applicable standard of care
    and, moreover, that she failed to show that the deviation from
    the check-your-mirror SOP caused her injury. We address the
    district court’s analysis of each SOP below.
    A
    Under the check-your-mirror SOP, a WMATA bus driver
    is expected to check his rearview mirror and “[m]ake sure all
    passengers are secure before moving the bus.” J.A. 938.
    According to Robinson’s expert, Dr. Berkowitz, “secure” means
    8
    that the passengers “are holding on to something.” J.A. 442.4
    The district court concluded both that Berkowitz’s testimony
    was insufficient to show that this SOP constituted a national
    standard of care in the public transportation industry, and that
    Robinson failed to show that violation of the SOP caused her
    injury.
    Ordinarily, the applicable standard of care is the traditional
    reasonable person standard, which the “jury can
    ascertain . . . without the aid of expert testimony.” Godfrey v.
    Iverson, 
    559 F.3d 569
    , 572 (D.C. Cir. 2009). But where “the
    subject in question is so distinctly related to some science,
    profession or occupation as to be beyond the ken of the average
    layperson,” the plaintiff must proffer expert testimony to
    establish the applicable standard of care. 
    Id. (internal quotation
    marks omitted); accord 
    Varner, 891 A.2d at 265
    . Put
    differently, an expert is necessary unless the subject matter is
    “within the realm of common knowledge and everyday
    experience” of average jurors. 
    Godfrey, 559 F.3d at 572
    (internal quotation marks omitted).
    When an expert witness is required, the expert must “clearly
    articulate and reference a standard of care by which the
    defendant’s actions can be measured.” 
    Varner, 891 A.2d at 269
    (internal quotation marks and emphasis omitted). Especially in
    cases involving safety standards, the expert must also show that
    4
    Dr. Berkowitz had initially tried to testify that the national
    standard of care required passengers to be seated before a bus driver
    started driving. But the district court barred that testimony on the
    ground that WMATA has an express policy permitting passengers to
    stand while riding a bus, and that this policy constitutes a
    “discretionary decision” that is “shielded from suit” under § 80 of the
    WMATA Compact. Robinson v. WMATA, 
    858 F. Supp. 2d 33
    , 37
    (D.D.C. 2012). Robinson does not appeal that ruling.
    9
    the particular practice at issue reflects a national standard of
    care. See, e.g., Novak v. Capital Mgmt. & Dev. Corp., 
    570 F.3d 305
    , 313 (D.C. Cir. 2009); 
    Briggs, 481 F.3d at 846-47
    ; Clark v.
    District of Columbia, 
    708 A.2d 632
    , 635 (D.C. 1997). An
    expert’s personal opinions or “unsupported assertion[s] as to the
    national standard of care” are insufficient. 
    Clark, 708 A.2d at 635
    . Further, although internal agency manuals such as
    WMATA’s standard operating procedures may provide evidence
    bearing on the standard of care, they do not, on their own,
    establish the national standard. 
    Briggs, 481 F.3d at 848
    ; 
    Varner, 891 A.2d at 269
    . Rather, the expert must show that the practices
    to which the agency has committed reflect “the national standard
    of care and not a higher, more demanding one.” 
    Clark, 708 A.2d at 636
    .
    Robinson argues, first, that the district court improperly
    required her to establish the standard of care via an expert
    witness. Indeed, we seriously doubt that determining whether
    it is reasonable to start a motor vehicle without checking to
    make sure one’s passengers are secure is outside “the realm of
    common knowledge and everyday experience” of average
    jurors. 
    Godfrey, 559 F.3d at 572
    ; see, e.g., 
    O’Neill, 633 A.2d at 841
    & n.14 (holding that an expert was not required to establish
    that a WMATA bus driver should have alerted the police when
    two drunk men loudly threatened and later assaulted another
    passenger aboard a Metrobus); WMATA v. Young, 
    731 A.2d 389
    ,
    396 (D.C. 1999) (holding that whether a bicyclist “was able to
    avoid colliding with” a city bus is not “beyond the ken of the
    average layperson”) (internal quotation marks omitted); cf. BOB
    DYLAN, Subterranean Homesick Blues, on BRINGING IT ALL
    BACK HOME (Columbia Records 1965) (“You don’t need a
    weatherman to know which way the wind blows.”).
    The problem is that Robinson forfeited this argument. The
    district court’s first opinion in this case, denying WMATA’s
    10
    motion for summary judgment, indicated that an expert was
    required to establish the standard of care because the subject was
    “beyond the ken of the average layperson.” Robinson v.
    WMATA, 
    858 F. Supp. 2d 33
    , 39 (D.D.C. 2012) (internal
    quotation marks omitted). Robinson did not demur. When
    WMATA moved for judgment as a matter of law at the close of
    Robinson’s case,5 the court again opined that “there has to be
    expert testimony about the national standard of care,” J.A. 603-
    04, and Robinson did not disagree. In accordance with its
    expressed view, the court then instructed the jury that, “You can
    only determine the standard of care required of WMATA from
    the testimony of the expert witnesses regarding that standard.”
    Jury Instructions 36, § 9.08. Again, Robinson did not object.
    Finally, when WMATA filed a renewed motion for judgment as
    a matter of law after the verdict, maintaining that an expert was
    required because the question was “beyond the ken of the
    average layperson,” J.A. 796, Robinson did not object on that
    ground.
    A “fundamental principle of appellate review generally bars
    a party who failed to preserve an argument in a lower tribunal
    from raising it on appeal absent plain error or exceptional
    circumstances.” Bahlul v. United States, 
    767 F.3d 1
    , 9 (D.C.
    Cir. 2014) (en banc); see Salazar ex rel. Salazar v. District of
    Columbia, 
    602 F.3d 431
    , 434 (D.C. Cir. 2010). We detect no
    exceptional circumstances here. And because District of
    Columbia courts have required expert testimony in many cases
    that, “on first blush, appear to be within the realm of common
    knowledge,” 
    Briggs, 481 F.3d at 845
    , we cannot find that it was
    plain error to require expert testimony to establish the standard
    of care in this case. See 
    id. (citing decisions
    requiring experts in
    cases involving the maintenance of leaning trees, the tightness
    5
    WMATA renewed that motion, by incorporation, at the
    conclusion of all of the evidence.
    11
    of handcuffs, the maintenance of street lights, and the choice
    between a crosswalk and a stop sign); 
    Burke, 685 F.3d at 1106
    n.2 (same).
    Robinson argues, second, that her expert’s testimony was in
    any event sufficient to establish that WMATA’s check-your-
    mirror SOP reflected a national standard. We admit to being
    tempted to delve more deeply into the question of whether this
    SOP really “developed from research, which actually dates back
    to Hammurabi” and “the book of Deuteronomy.” J.A. 458.6 But
    we need not resolve that question either. Whether or not Dr.
    Berkowitz successfully showed that the check-your-mirror SOP
    reflected a national standard, this negligence theory suffers from
    an independent ailment: lack of causation.
    As the district court correctly found, “Robinson did not
    introduce any evidence supporting a causal connection between
    the driver’s failure to check the internal center mirror and her
    injury.” Robinson, 
    941 F. Supp. 2d
    . at 69 n.5. If Bumpass had
    looked in the mirror, what would he have seen? According to
    Robinson’s testimony, he would have seen that she was holding
    onto a handrail, J.A. 512 -- exactly what Dr. Berkowitz testified
    the standard of care required him to confirm before moving the
    bus, see J.A. 442. Accordingly, had Bumpass followed the SOP,
    he would have done just what he did do -- move the bus -- and
    hence any deviation from the standard could not have caused
    Robinson’s injury.
    At oral argument, Robinson’s counsel attempted to remedy
    this fatal shortcoming by asserting that Robinson was not
    6
    Cf. CODE OF HAMMURABI § 197 (L.W. King. trans. 1915) (c.
    1780 B.C.), available at http://www.fordham.edu/halsall/ancient/
    hamcode.asp (“If he break another man’s bone, his bone shall be
    broken.”).
    12
    actually secure because she was only holding onto a seat-back
    handrail, as opposed to one of the bus’ vertical poles. Oral Arg.
    Recording at 16:49-17:26. But Dr. Berkowitz never testified
    that a passenger would not be considered “secure” unless she
    were holding on to a vertical pole (as opposed to a handrail). To
    the contrary, his testimony indicated that a passenger holding
    onto a handrail would be considered secure. J.A. 442 (stating
    that “we want to make sure that [passengers] are holding on to
    something”) (emphasis added). Therefore, Robinson failed to
    establish “a causal relationship between [Bumpass’] deviation
    and [her] injury.” 
    Varner, 891 A.2d at 265
    .7
    B
    Robinson’s effort to prove negligence by establishing a
    violation of the “start gradually, stop smoothly” SOP fares no
    better.
    First, Robinson’s argument that an expert was not required
    to establish this SOP as the standard of care fails for the same
    reason we identified above: She did not object to the jury
    instruction that required expert testimony to show that a
    WMATA operating procedure evidenced a national standard of
    7
    There is a second causation problem as well. The SOP in
    question says that a driver should check the mirror before moving the
    bus; it says nothing about checking before stopping the bus. But
    Robinson did not fall when the bus first began moving; she fell only
    as it came to a stop. Robinson argues that Bumpass’ start and
    subsequent stop were “packed into just seven seconds,” Robinson Br.
    29, suggesting that his failure to look in the mirror at the start had an
    effect that continued through the stop. In light of the causation
    problem identified in the text, we need not consider whether this
    argument is sufficient to bridge the gap between the start and the stop.
    13
    care. And as we said, that instruction did not constitute plain
    error.
    Second, as the district court found, WMATA cannot be
    liable for violations of the “start gradually and stop smoothly”
    SOP because that “would be inconsistent with District of
    Columbia law.” Robinson, 
    941 F. Supp. 2d
    . at 71. As we
    discuss in Part IV, WMATA is not liable under District law for
    the normal jerks and jolts commonly associated with bus travel.
    Johnson, 
    1991 WL 214174
    , at *2; 
    Fells, 357 A.2d at 395
    ; see
    Connor v. Wash. Ry. & Elec. Co., 
    43 App. D.C. 329
    , 333-34
    (D.C. 1915). Much more is required than merely failing to start
    gradually or stop smoothly. Rather, the common law of the
    District requires evidence that a jerk was of “extraordinary”
    force before an abrupt stop may be taken as proof of negligence.
    See Johnson, 
    1991 WL 214174
    , at *2; Fells v. WMATA, 
    357 A.2d 395
    , 395 (D.C. 1976). Accordingly, whether or not the
    “start gradually, stop smoothly” SOP reflects a nationally
    accepted practice, it cannot be the standard of care for purposes
    of a negligence action governed by District of Columbia tort
    law. Robinson cannot recover against WMATA merely by
    showing that Bumpass did not achieve a gradual start or a
    smooth stop.
    IV
    What remains is Robinson’s alternative argument that she
    provided circumstantial evidence of negligence by showing that
    the bus driver caused a jerk “so violent or extraordinary that it
    could not have been consistent with safe operation of the bus.”
    Johnson, 
    1991 WL 214174
    , at *2 (citing 
    Boyko, 468 A.2d at 584
    ; 
    Fells, 357 A.2d at 395
    -96). A plaintiff may pursue
    damages under this theory of liability without introducing expert
    testimony regarding the standard of care. See, e.g., Brighthaupt
    14
    v. WMATA, No. 97-7217, 
    1998 WL 794814
    , at *1 (D.C. Cir.
    1998).
    As we have just noted, WMATA is not liable for the normal
    “jerks or jars” that occur during city bus rides. 
    Fells, 357 A.2d at 395
    (quoting D.C. Transit System, Inc. v. Perry, 
    337 A.2d 224
    , 225 (D.C. 1975)). “Because ‘jerks’ occur often in the
    normal operation of a bus, evidence of a jerk that resulted in
    injury is not usually enough for a jury to infer negligence. If it
    were, WMATA could be held liable for many common
    accidents that are no fault of the driver.” Johnson, 
    1991 WL 214174
    , at *2. Instead, a plaintiff may “recover against the bus
    company only by showing ‘that the “jerk” or “sudden start” was
    of such unusual and extraordinary force that it could not
    reasonably be said to have happened in the ordinary operation
    of the vehicle.’” 
    Boyko, 468 A.2d at 583-84
    (quoting Wiggins
    v. Capital Transit Co., 
    122 A.2d 117
    , 118 (D.C. 1956)); see
    Brighthaupt, 
    1998 WL 794814
    , at *1.
    Such “‘unusual and extraordinary force,’” the District of
    Columbia Court of Appeals has said, “cannot be inferred from
    ‘mere descriptive adjectives and conclusions’ alone.” 
    Boyko, 468 A.2d at 584
    (quoting 
    Wiggins, 122 A.2d at 118
    ). Rather,
    reviewing courts must focus on “the substance of the testimony,
    not on its grammatical form.” 
    Id. The critical
    question “is
    whether the testimony, in whatever form it is offered, describes
    movement that is ‘consistent with proper operation of the bus.’”
    
    Id. (quoting WMATA
    v. Jones, 
    443 A.2d 45
    , 50 (D.C. 1982) (en
    banc)).
    In Boyko, for example, the plaintiff testified that the bus’
    jerk was “‘abrupt,’” “‘violent,’” and “unlike what she had come
    to expect in her fifty years of riding 
    buses.” 468 A.2d at 584-85
    .
    Her treating physician further testified that “her injury was one
    that ‘takes a considerable amount of violence.’” 
    Id. at 583.
                                   15
    Finally, the bus driver admitted that, “when she pulled away
    from the stop, she knew that the floor was wet and that appellant
    had not yet reached a seat.” 
    Id. Taken together,
    this testimony
    was sufficient to send the case to a jury. 
    Id. at 585.
    In Johnson,
    by contrast, a witness’ statement that a bus’ jerk “wasn’t
    normal” was insufficient. 
    1991 WL 214174
    , at *2. Likewise
    insufficient was the testimony of Johnson’s doctor, who “did not
    testify that the injury could only have been caused by a violent
    motion of the bus.” 
    Id. In support
    of her claim that her bus experienced an
    extraordinary and violent jerk, Robinson testified that the bus
    was going “fast, faster than normal buses,” J.A. 513, and that it
    “was jerking and then [there] was an abrupt stop,” J.A. 528.
    When asked how fast the bus was moving, Robinson said: “I
    was not facing the driver, so I wasn’t aware of the speed. But I
    could see the trees at the park going by swiftly as I was
    proceeding to a seat.” J.A. 513. The abrupt stop, she testified,
    caused her to lose her grip on the handrail and fall. J.A. 528-29.
    As an initial matter, we reject WMATA’s contention that
    Robinson’s testimony was insufficient merely because no other
    witness corroborated it. It is true that plaintiffs who recover
    under this theory often present testimony of non-party witnesses
    who can in some manner corroborate the extreme nature of the
    bus’ jerk. See, e.g., 
    Boyko, 468 A.2d at 585
    ; Brighthaupt, 
    1998 WL 794814
    , at *1. But the District of Columbia cases do not
    hold that a plaintiff cannot recover on the basis of her testimony
    alone. To the contrary, as the Boyko court observed, if
    WMATA is arguing that there is “some fancied defect in . . . the
    self-evident interest of a party in the outcome of the case, it is
    
    unpersuasive.” 468 A.2d at 584
    .
    Nonetheless, we agree with the district court that
    Robinson’s testimony “does not give rise to an inference that the
    16
    deceleration was ‘of such unusual and extraordinary force that
    it could not reasonably be said to have happened in the ordinary
    operation of the vehicle.’” Robinson, 
    941 F. Supp. 2d
    at 73
    (quoting 
    Boyko, 468 A.2d at 584
    ). The strongest part of her
    testimony -- that the bus was traveling “fast, faster than normal
    buses” -- is not enough to recover on this theory. See 
    Boyko, 468 A.2d at 584
    (distinguishing as insufficient such testimony
    in 
    Perry, 337 A.2d at 225
    , where the plaintiff described the bus’
    movement as “unusually fast”). Robinson acknowledged that
    she “wasn’t aware of the [bus’] speed,” J.A. 513, and she
    provided no context for what she meant by “normal.” Traveling
    faster than “normal” does not mean that the movement was
    inconsistent with safe or proper operation, let alone that the stop
    was. Nor was Robinson’s testimony -- that the bus’ movement
    was “jerking” and the stop “abrupt” -- inconsistent with a
    description of the jerks and jolts that commonly occur aboard
    city buses. See 
    Fells, 357 A.2d at 395
    . Under District law,
    “‘testimony of a sudden stop and resulting injuries does not, by
    itself, raise a permissible inference of negligence.’” 
    Boyko, 468 A.2d at 584
    (quoting 
    Fells, 357 A.2d at 395
    -96); cf. 
    Wiggins, 122 A.2d at 118
    (noting that “statements that a street car ‘started
    violently,’ ‘started with a violent jerk,’ . . . and the like, are not
    of themselves sufficient to show negligent operation” (citation
    omitted)).
    The testimony of Robinson’s biomedical expert, Dr.
    Williams, does not rescue her case. Dr. Williams was not
    Robinson’s treating physician and never talked to her. J.A. 243.
    Williams did testify that, assuming Robinson was holding the
    handrail with the maximum grip strength of a woman of similar
    age and weight, the “deceleration that would have destabilized
    her” would have been about “.38 times gravity.” J.A. 207. But
    assuming that “.38 times gravity” constitutes an extraordinary or
    violent force (no evidence was offered on the point), there was
    no testimony that Robinson was capable of exerting the
    17
    maximum grip strength of a woman of her age and weight, and
    no testimony that she was holding on as tightly as she could.
    Indeed, Dr. Williams acknowledged that she had no information
    at all regarding how tightly Robinson was actually holding the
    handrail, and agreed that, if Robinson were “not holding onto
    the hand hold with everything she’s got, it would take
    less . . . deceleration to disrupt her grip.” J.A. 227-28. As a
    consequence, Williams’ testimony left the jury unable to do
    anything more than speculate about the actual force of the stop.
    And “[s]ufficiency of the evidence to support a claim for relief
    may not be established by jury speculation.” Milone v. WMATA,
    
    91 F.3d 229
    , 232 (D.C. Cir. 1996).
    In sum, because Robinson’s testimony was “consistent with
    proper operation of the bus,” and because a jury could only infer
    from Dr. Williams’ testimony “that it was possible that Ms.
    Robinson’s injury resulted from significant force,” Robinson,
    
    941 F. Supp. 2d
    at 73-74 (internal quotation marks omitted), the
    district court properly granted judgment as a matter of law in
    favor of WMATA.
    V
    For the foregoing reasons, we conclude that neither of the
    two negligence theories proffered by the plaintiff was supported
    by evidence sufficient to sustain a jury verdict in her favor. The
    judgment of the district court is therefore
    Affirmed.