UNITED STATES DISTRICT COURT FOR THE DISTRICT OF COLUMBIA
BRUCE BUNTING, et al.,
Plaintiffs,
v. Civil Action No. 22-cv-766
DISTRICT OF COLUMBIA CVS PHARMACY, LLC,
Defendant.
MEMORANDUM OPINION Plaintiffs Dr. Bruce Bunting and Jessie Brinkley (“Plaintiffs”) bring this suit against
Defendant District of Columbia CVS Pharmacy, LLC (“CVS”) for damages arising out of personal
injuries that Dr. Bunting allegedly suffered during an incident at CVS’ premises in Northwest,
Washington, D.C. (the “CVS Store”). ECF No. 1-1 at 1.
Before the Court is the Plaintiffs’ Motion to Strike All Opinion Testimony of Defendant’s
Expert Witness Alexandra Maddox (“Motion”). ECF No. 45. For the following reasons, the Court
DENIES Plaintiffs’ Motion.
FACTUAL SUMMARY
The Plaintiffs allege that on December 24, 2020, Dr. Bunting slipped and fell outside the
automatic exit doors at the CVS Store. ECF No. 1-1 at 2. Dr. Bunting claims that he slipped on
“slick and wet concrete that resulted from a mixture of salt and water.” Id. at 3. The Plaintiffs
allege that CVS created the slick surface by “spreading [] the salt on a wet and warm day, which
caused it to make the ground unsafe and slippery.” Id. at 3. According to the Plaintiffs, the CVS
Store was “negligently kept, maintained, and operated, creating an unreasonable risk of injury to
invitees,” including Dr. Bunting. Id. at 4. As a result of the fall, Dr. Bunting allegedly suffered a
1 “closed fracture dislocation of his right ankle” that required surgery. Id. at 3. The Plaintiffs further
allege that CVS’ negligence caused Dr. Bunting to suffer “serious bodily and emotional injuries
and damages, including physical pain, suffering, emotional distress, inconvenience, loss of the
enjoyment of life, and medical expenses.” Id. at 4.
One of CVS’ designated expert witnesses is Alexandra Maddox, a mechanical engineer
and biomedical engineer. ECF No. 33 at 4. Maddox’s expert report details her investigation,
including slip resistance testing she conducted on January 19, 2023 on the incident walkway
surface at the CVS Store, and provides her opinions regarding the slip resistance of the walkway
surface. ECF No. 33-5. As part of her slip resistance testing, Maddox used an English XL Variable
Incident Tribometer (“VIT”), a device used for slip resistance testing in different environments.
Id. at 9, 14. A VIT is designed to yield coefficient of friction (“COF”) measurements that correlate
to the likelihood of slip incidents occurring on a given surface. Id. at 14. Maddox used a VIT that
Excel Tribometers, the manufacturer of the English XL VIT, calibrated three days before her field
test. Id. at 9. Maddox then field calibrated the VIT the day before her field test. Id.
According to CVS, Maddox’s VIT was validated and calibrated in accordance with
American Society for Testing and Materials (“ASTM”) standard F2508. ECF No. 49 at 1, 2.
Maddox also applied American National Standards Institute (“ANSI”) standard A1264.2, which
recommends a COF of 0.5 or greater for walking surfaces in the workplace under dry or wet
conditions. ECF No. 33-5 at 4, 14. CVS asserts that Maddox “obtained slip resistance
measurements under both wet and dry scenarios” pursuant to ANSI A1264.2. ECF No. 49 at 16.
Consistent with the VIT device manual, Maddox used only water for the wet testing. Id.
2 Maddox concluded that the walkway surface had a COF of 0.64 ± .03 when dry and 0.51
± .03 when wet. 1 ECF No. 33-5 at 9. According to Maddox, the salt and water solution that Dr.
Bunting described slipping on “is less lubricating than water on a walking surface, and creates
greater slip resistance than water alone.” Id. at 16. Maddox therefore concluded, among other
things, that “the incident walking surface was reasonably safe for pedestrian traffic” and “[t]here
is insufficient evidence to support the claim that the incident walkway caused [Dr. Bunting’s] fall.”
Id.
PROCEDURAL HISTORY
The Plaintiffs filed a Complaint on February 14, 2022 in the Superior Court of the District
of Columbia. ECF No. 1 at 1. The Complaint includes three counts: (1) negligence – premises
liability; (2) negligence per se; and (3) loss of consortium. ECF No. 1-1 at 4–8. The Plaintiffs
seek the following relief: (1) compensatory damages in the amount of $2,000,000; (2) payment of
all costs associated with this case; (3) pre- and post-judgment interest; and (4) “such other and
further relief as this Court deems proper.” Id. at 8. CVS removed the case to this Court on March
21, 2022 based on diversity of citizenship. ECF No. 1.
ANALYSIS
I. Standard of Review
The Plaintiffs seek to exclude all of Maddox’s opinion testimony pursuant to Rule 702 of
the Federal Rules of Evidence, Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579 (1993), and
Kumho Tire Co., Ltd. v. Carmichael, 526 U.S. 137 (1999). ECF No. 45 at 1. Under Rule 702, a
1 As part of their response to CVS’ Motion for Summary Judgment (ECF No. 47), the Plaintiffs assert that after the close of discovery, CVS produced Maddox’s field notes that show that the area “directly outside the exit door where Dr. Bunting slipped and fell had an average coefficient of friction of 0.49 when wet.” ECF No. 52 at 1.
3 district court “must determine as an initial matter whether the proffered witness is qualified to give
the expert opinion he seeks to offer.” Moore v. Napolitano, 926 F. Supp. 2d 8, 16-17 (D.D.C.
2013). The Court may then admit a qualified expert’s testimony only if it is both relevant and
reliable. Id. at 17.
A. Expert Qualification Under Rule 702 and Daubert
As a general matter, “trial courts have broad discretion when deciding whether a witness
qualifies as an expert.” 29 Charles Alan Wright & Arthur R. Miller, Federal Practice and
Procedure (“Wright and Miller”) § 6264.2 (2d ed. 2023). Rule 702 recognizes five specific bases
for qualifying an expert: knowledge, skill, experience, training, and education. Fed. R. Evid. 702.
Background in just one of these bases is sufficient, but if an expert has some background in
multiple bases, the Court may consider the totality of the witness’s background. Wright and Miller
§ 6264.1. No matter which bases are at issue, the expert’s background must match the subject
matter of the expert’s testimony. Id. § 6264.2.
A qualified expert may testify “if the proponent demonstrates to the court that it is more
likely than not that,” among other things, “the expert’s scientific, technical, or other specialized
knowledge will help the trier of fact to understand the evidence or to determine a fact in issue.”
Fed. R. Evid. 702(a). The degree of knowledge, skill, experience, training, or education required
to qualify an expert witness “is only that necessary to insure [sic] that the witness’s testimony
assist the trier of fact.” Khairkhwa v. Obama, 793 F. Supp. 2d 1, 11 (D.D.C. 2011) (internal
quotation marks omitted), aff’d, 703 F.3d 547 (D.C. Cir. 2012). A trial court may not exclude
expert testimony “simply because [it] does not deem the proposed expert to be the best qualified
or because the proposed expert does not have the specialization that the court considers most
appropriate.” Heller v. D.C., 952 F. Supp. 2d 133, 140 (D.D.C. 2013). To that end, the relevant
inquiry with respect to an expert’s qualifications is not her qualifications in the abstract, but 4 “whether those qualifications provide a foundation for a witness to answer a specific question.”
Berry v. City of Detroit, 25 F.3d 1342, 1351 (6th Cir. 1994) (emphasis added).
In the context of slip-and-fall cases, federal courts have ruled that certified tribometrists
are qualified under Rule 702 to offer opinion testimony about the slip resistance of a walkway
surface. See, e.g., Kessler v. NCL (Bahamas) Ltd., No. 19-CV-20583, 2019 WL 8128483, at *4
(S.D. Fla. Dec. 20, 2019); Ward v. Carnival Corp., No. 17-CV-24628, 2019 WL 1228063, at *4
(S.D. Fla. Mar. 14, 2019); Michaels v. Taco Bell Corp., Civ. No. 10-1051, 2012 WL 4507953, at
*6 (D. Or. Sept. 27, 2012); Stern v. NCL Bahamas Ltd., No. 19-CV-20280, 2020 WL 6820877, at
*5 (S.D. Fla. Sept. 28, 2020).
B. Reliability Under Rule 702 and Daubert
Daubert established the district court’s role as a “gatekeeper[] to exclude unreliable expert
testimony.” U.S. ex rel. Miller v. Bill Harbert Int’l Const., Inc., 608 F.3d 871, 894 (D.C. Cir.
2010) (citing Daubert, 509 U.S. at 579). In fulfilling its gatekeeper role, a district court has “broad
discretion in determining whether to admit or exclude expert testimony.” Id. Although district
courts may apply various factors to assess reliability, the Supreme Court provided the following
five factors to guide the inquiry: (1) whether the technique has been or can be tested; (2) whether
the technique has a known or potential rate of error; (3) whether the technique has been subject to
peer review and publishing; (4) the existence and maintenance of standards controlling the
technique’s operation; and (5) whether the technique has been generally accepted within the
relevant scientific community. Daubert, 509 U.S. at 593–94. Under Daubert, a trial court must
focus “solely on principles and methodology, not on the conclusions that they generate.” Id. at
595. Further, the Court need only determine whether the expert’s science “has the earmarks of
validity” and not whether it is, in fact, scientifically valid. Wright & Miller § 6267.
5 This Court has stated that “[i]n considering Rule 702 motions, the court assumes only a
limited gate-keeping role directed at excluding expert testimony that is based upon subjective
belief or unsupported speculation.” Heller, 952 F. Supp. 2d at 140 (internal quotation marks
omitted). Further, the Court “is supposed to screen the jury from unreliable nonsense opinions,
but not exclude opinions merely because they are impeachable.” Alaska Rent-A-Car, Inc. v. Avis
Budget Grp., Inc., 738 F.3d 960, 969 (9th Cir. 2013). According to the D.C. Circuit, expert
testimony is not reliable when it is based on “guesswork, speculation, and conjecture.” Joy v. Bell
Helicopter Textron, Inc., 999 F.2d 549, 568 (D.C. Cir. 1993). This Court has stated that “[e]xpert
testimony should be excluded only when it is based on ‘guesswork, speculation, and conjecture.’”
United States v. Slough, 22 F. Supp. 3d 25, 29 (D.D.C. 2014) (quoting Joy, 999 F.2d at 568)
(emphasis added). To that end, “[t]he presumption under [Rule 702] is that expert testimony is
admissible once a proponent makes the requisite threshold showing; further disputes go to weight,
not admissibility.” United States v. Machado-Erazo, 950 F. Supp. 2d 49, 52 (D.D.C. 2013) (citing
Daubert, 509 U.S. at 588).
With respect to measuring slip resistance, a VIT is “commonly relied on by experts in slip
and fall cases all over the United States.” Piazza v. Target Corp., No. 21-CV-835, 2022 WL
16923867, at *1 n.1 (M.D. Fla. Nov. 14, 2022). Indeed, numerous federal courts have ruled that
VIT testing is reliable under Rule 702. See, e.g., id.; Barnes v. Malinak, 320 F.R.D. 130, 139 (E.D.
Tenn. 2017); Darby v. Carnival Corp., No. 19-21219-CIV, 2021 WL 6428039, at *10 (S.D. Fla.
Nov. 23, 2021), adopted by, No. 19-21219-CIV, 2022 WL 112193 (S.D. Fla. Jan. 12, 2022); Armas
v. Costco Wholesale Corp., No. 21-cv-01528, 2022 WL 17982239, at *5 (D. Nev. Nov. 30,
2022); Feuerstein v. Home Depot, U.S.A., Inc., No. 12-cv-01062, 2014 WL 2616582, at *3 (D.
Ariz. June 12, 2014); Atkinson v. Carnival Corp., No. 20-20317-CIV, 2021 WL 8534238, at *4
6 (S.D. Fla. Nov. 29, 2021); Steffen v. Home Depot U.S.A., Inc., No. CV-13-199, 2014 WL 1494108,
at *6 (E.D. Wash. Apr. 16, 2014). At least one federal court has based its denial of a Rule 702
motion challenging the reliability of VIT testing in part on the fact that the expert’s VIT passed
ASTM F2508 validation. See Armas, 2022 WL 17982239, at *5.
In denying Rule 702 motions that challenge the reliability of VIT testing, federal courts
have ruled that any alleged defects in the methodology of VIT testing go to the weight of the
expert’s opinion, not its admissibility. See, e.g., Barnes, 320 F.R.D. at 139; Atkinson, 2021 WL
8534238, at *4; Darby, 2021 WL 6428039, at *10. For example, although the court in Barnes
noted that it was “concerned that [the expert] did not use the tribometer as the manufacturer
intended and was not certain when the device had been calibrated,” it nonetheless denied the Rule
702 motion because “‘vigorous cross-examination, presentation of contrary evidence, and careful
instruction on the burden of proof are the traditional and appropriate means of attacking shaky but
admissible evidence.’” 320 F.R.D. at 139 (quoting Daubert, 509 U.S. at 596).
II. The Plaintiffs’ Motion to Strike
A. Maddox Is Qualified to Offer Opinion Testimony Regarding the Slip Resistance of the Walkway Surface at the CVS Store.
The Plaintiffs argue that Maddox is not qualified under Rule 702 to provide expert
testimony regarding the slip resistance of the walkway surface at the CVS Store. ECF No. 45-1 at
17–19; ECF No. 51 at 1–3. In support of this argument, the Plaintiffs assert that “[a]ccording to
her CV, Ms. Maddox is not a licensed professional engineer, a certified safety specialist, a certified
Variable Incidence Tribometrist, or even a human factors expert and has no experience in testing
or evaluating walking surfaces for slipperiness.” ECF No. 45-1 at 17. The Plaintiffs also assert
that Maddox’s ongoing work as a Ph.D. student is not related to walkway surfaces or testing of
materials. Id. The Plaintiffs further argue that Maddox’s Occupational Safety and Health
7 Administration (“OSHA”) accreditations in general industry standards do not reflect an expertise
in walkway safety because they were minimally focused on walkway safety and fall protection.
ECF No. 51-1 at 2.
In support of their argument, Plaintiffs cite a slip-and-fall case in which the expert “was a
registered Professional Engineer, Certified Safety Professional, and Certified Variable Incidence
Tribometrist, who [held] a [m]aster’s [d]egree in Industrial Safety Engineering and [a] Ph.D. in
Interdisciplinary Engineering ‘with a focus on Workplace, Premises, Product Safety, Human
Factors, and Industrial Engineering.’” ECF No. 45-1 at 17 (quoting Ruston v. Office Depot, Inc.,
No. 10-CV-05057, 2011 U.S. Dist. LEXIS 119558, at *3 (W.D. Mo. Oct. 17, 2011)). The Plaintiffs
also cite cases outside the slip-and-fall context in which an expert appeared to be well educated,
have extensive experience in a certain field, or both, but nonetheless failed to qualify under Rule
702 because the expert did not possess the requisite knowledge, skill, experience, training, or
education in the relevant field. Id. at 18–19 (citing Meridia Products Liability Litigation v. Abbott
Laboratories, 447 F.3d 861, 868–69 (6th Cir. 2006); Brown v. Raymond Corp., 432 F.3d 640, 641,
649–50 (6th Cir. 2005); and Advanced Med. Optics, Inc. v. Alcon Inc., No. 03-1095, 2005 U.S.
Dist. LEXIS 5803, at *13 (D. Del. Apr. 7, 2005)).
CVS argues that Maddox is qualified under Rule 702 to offer expert opinions on the slip
resistance and reasonable safety of the walkway surface because, contrary to the Plaintiffs’
assertion, Maddox is a Certified English XL Tribometrist (“CXLT”) and “possesses a valid CXLT
Certificate.” ECF No. 49 at 7. This certification process included classroom and field training
provided by the device manufacturer and required Maddox to demonstrate proper operational
technique of the device in both a written examination and a field proficiency test. Id. at 7–8. In
light of Maddox’s CXLT certificate, CVS argues that “when the ‘specific question’ relates to the
8 slip resistance of a walkway surface, the federal district courts are uniform in finding that a
certified tribometrist is qualified to offer those opinions.” Id. at 9 (citing Kessler, 2019 WL
8128483, at *4; Michaels, 2012 WL 4507953, at *6; Stern, 2020 WL 6820877, at *5). It would
be “illogical,” according to CVS, “for this Court to conclude that Ms. Maddox is not qualified to
perform slip resistance testing using a VIT when the company that manufactures the very device
that she used has certified that she is qualified to do so.” Id.
According to CVS, “Rule 702 does not require an expert witness to possess a Ph.D. or to
be a certified safety specialist to be qualified to render expert opinions on the slip resistance of a
walkway surface.” Id. at 8 (internal quotation marks omitted). As a result, Maddox “more than
meets the qualifications necessary to testify with respect to the testing she performed with a device
she is certified to use, and the conclusions that she reached as a result of her testing and
investigation.” Id. at 9. CVS also notes that Maddox “has a bachelor’s degree in biomedical
engineering, has nearly completed her Ph.D., and has completed two accredited courses in OSHA
general industry standards, including walkway safety.” Id. at 8.
The Court finds that Maddox is qualified under Rule 702 to offer opinion testimony
regarding the slip resistance of the walkway surface at the CVS Store. The Plaintiffs are incorrect
to suggest that Maddox is not a CXLT. Maddox obtained her CXLT certification “following
classroom and field training provided by” the manufacturer of the VIT that Maddox later used to
perform a field test of the walkway surface at the CVS Store. ECF No. 49-4 at 1–3. Maddox then
detailed the results of that field test in her expert report and explained why those results led her to
conclude, among other things, that the walkway surface “was reasonably safe for pedestrian
traffic.” ECF No. 33-5 at 16. Importantly, Maddox’s certification applies not only to her operation
of the VIT, but also to her “interpret[ation] of the results obtained in field tests utilizing the VIT.”
9 ECF No. 49-4 at 2. Given that the slip resistance of the walkway surface at the CVS Store is
directly relevant to the Plaintiffs’ negligence claims, Maddox’s CXLT certification is sufficient to
ensure that her testimony will “assist” the trier of fact under Rule 702. See Khairkhwa, 793 F.
Supp. 2d at 11 (D.D.C. 2011); see also ECF No. 48-1 at 22 (providing Plaintiffs’ expert’s opinion
that Dr. Bunting’s injury was caused by “a very slippery and an unreasonably unsafe and dangerous
walkway surface condition.”).
As CVS notes, several federal courts have ruled that a certified tribometrist is qualified
under Rule 702 to offer opinion testimony about the slip resistance of a walkway surface. See,
e.g., Kessler, 2019 WL 8128483, at *4; Ward, 2019 WL 1228063, at *4; Michaels, 2012 WL
4507953, at *6; Stern, 2020 WL 6820877, at *5. Plaintiffs do not identify any case in which a
court has ruled that a certified tribometrist is not qualified to offer opinion testimony about the slip
resistance of a walkway surface.
The outcome does not change merely because the experts in cases upon which CVS relies
may have had stronger credentials than Maddox in this particular area. For example, the expert in
Michaels had “substantial experience as a consulting engineer” in addition to being a certified
tribometrist. 2012 WL 4507953, at *6. Similarly, the expert in Stern was a certified tribometrist
who also specialized in slips, trips, falls, and industrial and premises safety, participated in crash
investigations, and completed continuing education courses in accident reconstruction. 2020 WL
6820877, at *5. This Court may not, however, exclude Maddox’s testimony simply because it
believes Maddox is not “the best qualified” or because Maddox “does not have the specialization
that the court considers most appropriate.” Heller, 952 F. Supp. 2d at 140. Maddox’s status as a
CXLT renders her able to help the jury determine the slip resistance of the walkway surface at the
10 CVS Store and, in turn, whether CVS was negligent in its treatment of the walkway surface. See
Fed R. Evid. 702(a). Maddox, therefore, meets the qualification standard under Rule 702.
B. Maddox’s Opinion Testimony Meets the Threshold Requirements for Reliability.
Plaintiffs also argue that the Court should exclude all of Maddox’s opinion testimony
because Maddox’s VIT testing methodology is “[u]nreliable [f]lawed [s]cience.” ECF No. 45-1
at 9. Plaintiffs make several specific arguments regarding reliability. First, they argue that ASTM
F2508 cannot be used to establish a safe threshold value for a walkway surface because: (1) it is
based on VIT measurements from young adults walking in a straight path on a level surface,
whereas Dr. Bunting was 73 years old at the time of the incident and was stepping over a door
onto a slanted surface; (2) its test subjects walked in shoes that are not representative of all shoes;
(3) its use does not imply proper validation and calibration under all combinations of test materials
and walkway surfaces; and (4) it does not purport to address all safety concerns associated with its
use. ECF No. 45-1 at 10–12.
Second, Plaintiffs assert that recent studies and publications, including by ASTM,
demonstrate the unreliability of VIT testing. Id. at 12–14. Third, the Plaintiffs note that, in 2006,
ASTM withdrew ASTM F1679—a VIT testing standard that ASTM originally published in
2004—because it lacked precision and bias testing. ECF No. 45-1 at 14–15. According to
Plaintiffs, ASTM F1679’s withdrawal illustrates that VIT testing is unreliable. Id. at 15. Fourth,
Plaintiffs assert that Maddox has not demonstrated that she complied with ASTM’s calibration
requirements to use a VIT. Id. at 16–17. Plaintiffs cite to Kill v. City of Seattle, No. 70767-1-I,
2014 Wash. App. LEXIS 2094 (Ct. App. Aug. 25, 2014), in which the court ruled that an expert’s
opinion testimony was unreliable because, among other things, the expert’s VIT “was not properly
11 calibrated under the ASTM F2508 standard at the time of [the expert’s] second field test.” Id. at
*14; ECF No. 45-1 at 17; ECF No. 51 at 7.
In Maddox’s defense, CVS cites to various federal courts that have ruled that VIT testing
is reliable under Rule 702. ECF No. 49 at 10–11. CVS also rejects the Plaintiffs’ suggestion that
ASTM F2508 cannot be used to determine the reasonable safety of a walking surface. See id. at
11–13. According to CVS, ASTM F2508 “does not purport to establish what does and what does
not constitute a safe walking surface.” Id. at 12. Instead, it “is a control that governs the . . .
operation of tribometers to be able to accurately measure the COF value, which, in turn, can be
used to evaluate the safety of a walkway surface.” Id. at 13 (internal quotation marks omitted).
CVS also argues that the studies upon which Plaintiffs rely to assert that VIT testing is
unreliable merely recommend that slip resistance measurements account for variability, as
Maddox’s measurements did. Id. at 18–19. With respect to the Plaintiffs’ argument about ASTM
F1679’s withdrawal, CVS notes that Maddox did not rely on this standard and that a federal court
rejected this argument in ruling that VIT testing is reliable. Id. at 20–21. CVS also asserts,
contrary to the Plaintiffs’ suggestion, that the manufacturer of Maddox’s VIT calibrated the device
three days before Maddox’s field test and that Maddox herself field calibrated the same device the
day before her field test. Id. at 13–14. Further, CVS argues that Maddox performed her testing
according to the specifications of the VIT manual and her training, yielding “reliable” and
“reproducible” results. Id. at 15. More generally, CVS argues that Plaintiffs’ attack on Maddox’s
conclusions “is more properly characterized as cross-examination material” and “is not a proper
basis to seek to exclude her opinions under Rule 702 and/or Daubert.” Id. at 21.
Maddox’s VIT testing meets the threshold reliability requirements under Rule 702 and
Daubert. Federal courts have often denied Rule 702 motions challenging the reliability of VIT
12 testing. See, e.g., Barnes, 320 F.R.D. at 139; Piazza, 2022 WL 16923867, at *1–2; Darby, 2021
WL 6428039, at *10; Armas, 2022 WL 17982239, at *5; Feuerstein, 2014 WL 2616582, at *3;
Atkinson, 2021 WL 8534238, at *4; Steffen, 2014 WL 1494108, at *6. Further, Maddox used an
ASTM F2508-validated VIT, which strengthens the reliability of her methodology. ECF No. 33-
5 at 14; see Armas, 2022 WL 17982239, at *5. Indeed, Maddox’s methodology appears to be even
more reliable than the expert’s methodology in Barnes, in which the court denied a Rule 702
motion despite acknowledging that “the Court is concerned that [the expert] did not use the
tribometer as the manufacturer intended” and that the expert “was not certain when the device had
been calibrated.” 320 F.R.D. at 139. Here, in contrast, Maddox performed her testing in
accordance with the manufacturer’s manual, and both the manufacturer and Maddox calibrated the
VIT within three days of the field test. ECF No. 33-5 at 9; ECF No. 49-4 at 3, Ex. 6 at 18–21.
Significantly, Plaintiffs do not identify any instance in which a federal court has found VIT
testing to be an unreliable methodology. To be sure, Plaintiffs do identify one state court case in
which the court excluded an expert’s VIT test results. Britz v. Aria Resort & Casino, No. A-18-
770380-C, 2020 Nev. Dist. LEXIS 111, at *4 (Jan. 31, 2020). In that case, however, the court
provided no explanation or analysis beyond its conclusion that ANSI A1264.2 “is not a standard
but a recommendation” and that English XL testing “is not published or peer-reviewed.” Id.
Without more, this state court decision is insufficient to overcome the extensive federal decisions
rejecting Rule 702 challenges to the reliability of VIT testing.
The various arguments Plaintiffs make regarding VIT testing go to the weight of the
evidence, not its admissibility. Once a court determines that an expert is qualified under Rule 702,
it “assumes only a limited gate-keeping role directed at excluding expert testimony that is based
upon subjective belief or unsupported speculation.” Heller, 952 F. Supp. 2d at 140 (internal
13 quotation marks omitted). In this Circuit, expert testimony is not reliable when it is based on
“guesswork, speculation, and conjecture.” Joy, 999 F.2d at 568.
Plaintiffs’ argument that Maddox’s reliance on ASTM F2508 renders her methodology
unreliable is not persuasive. As noted above, federal courts have consistently ruled that VIT testing
is reliable, including when the VIT is validated by ASTM F2508. E.g., Darby, 2021 WL 6428039,
at *10, adopted by, 2022 WL 112193; Armas, 2022 WL 17982239, at *5. Moreover, ASTM F2508
is an “international standard” that is “intended to establish the procedures for validation,
calibration, and certification of [VITs].” ECF 45-4 at 1. Maddox, therefore, relied on a standard
that is intended to control the operation of VITs, which weighs in favor of reliability under
Daubert. 509 U.S. at 594 (directing courts to consider “the existence and maintenance of standards
controlling the technique’s operation” when evaluating the reliability of a scientific technique).
Even if the Court were to accept the Plaintiffs’ assertions that ASTM F2508 is “based on an
unrepresentative sample of humans that are nothing like Dr. Bunting,” it cannot be said that
Maddox’s testimony is “based upon subjective belief or unsupported speculation.” ECF No. 45-1
at 11–12; Heller, 952 F. Supp. 2d at 140.
Similarly, the studies and publications upon which Plaintiffs rely to raise concerns about
VIT testing do not support excluding Maddox’s testimony. These sources discuss the need to
consider measurement uncertainty when interpreting VIT testing results. See, e.g., ECF No. 45-5
at 1; ECF No. 45-6 at 12. As CVS points out, however, Maddox accounted for uncertainty by
testing the surface at different locations and presenting the slip index values as “mean ± standard
deviation.” ECF No. 45-1 at 12–14; ECF No. 49 at 19; ECF No. 33-5 at 9. To the extent that
Plaintiffs disagree with the extent to which Maddox accounted for uncertainty in her conclusions,
14 Plaintiffs can address this issue through “vigorous cross-examination, presentation of contrary
evidence, and careful instruction on the burden of proof.” Daubert, 509 U.S. at 596.
Plaintiffs’ remaining arguments are unpersuasive. Plaintiffs argue that ASTM’s decision
in 2006 to withdraw ASTM F1679 renders Maddox’s testing unreliable, but Maddox did not rely
on ASTM F1679 in her report. ECF No. 45-1 at 14–16. Indeed, Plaintiffs do not suggest that any
of the standards upon which Maddox relies have been withdrawn. Finally, Plaintiffs assert that
Maddox “failed to demonstrate that she had calibrated her [VIT] correctly,” but as discussed above,
the manufacturer calibrated Maddox’s VIT three days before the field test and then Maddox field
calibrated her VIT the day before the field test. Id. at 16; ECF No. 33-5 at 6. Any potential
deficiencies in how the manufacturer or Maddox calibrated the VIT go to the weight of the
evidence, not its admissibility. See Daubert, 509 U.S. at 596.
CONCLUSION
For the foregoing reasons, the Court DENIES Plaintiffs’ Motion, ECF No. 45. A separate
order will issue.
SO ORDERED.
Date: February 7, 2024
____________________________________ MOXILA A. UPADHYAYA UNITED STATES MAGISTRATE JUDGE