In the

    United States Court of Appeals
                 For the Seventh Circuit
                     ____________________
No. 19‐2984
MOSES PEREZ and DEE PEREZ,
                                                Plaintiffs‐Appellants,
                                 v.

K & B TRANSPORTATION, INC. and KIARA WHARTON,
                                     Defendants‐Appellees.
                     ____________________

         Appeal from the United States District Court for the
           Northern District of Illinois, Eastern Division.
           No. 1:17‐cv‐02610 — Mary M. Rowland, Judge.
                     ____________________

       ARGUED JUNE 5, 2020 — DECIDED JULY 24, 2020
                ____________________

   Before EASTERBROOK, HAMILTON, and SCUDDER, Circuit
Judges.
    HAMILTON, Circuit Judge. Plaintiff Moses Perez was driving
a sport‐utility vehicle when he apparently hit a patch of ice,
lost control, and was then hit from behind by defendant Kiara
Wharton driving a tractor‐trailer. After excluding Perez’s ex‐
pert witnesses on accidents and truck‐driving, the district
court granted summary judgment for Wharton and her em‐
2                                                   No. 19‐2984

ployer, K & B Transportation, Inc. We conclude that this clas‐
sic negligence case was inappropriate for summary adjudica‐
tion. Under Illinois law, a reasonable jury could infer that
Wharton was driving negligently based on the evidence that
she rear‐ended Perez and that she was driving too fast for the
weather conditions. We reverse and remand for trial.
I. Facts for Summary Judgment
    Because defendants K & B Transportation and Wharton
moved for summary judgment, on appeal we construe the
facts in the light most favorable to the non‐moving parties,
Moses Perez and his wife Dee Perez. Reid v. Norfolk & W. Ry.
Co., 

, 1110 (7th Cir. 1998). The accident occurred
at 5:18 am on January 20, 2016, seconds after both vehicles
passed the toll sensors at a toll plaza on eastbound Interstate
294 in Thornton Township in southeastern Cook County, Illi‐
nois. The posted speed limit was 55 miles per hour. It was
dark, and the weather was cold, snowy, and icy.
    Perez’s vehicle, driving in the right I‐Pass lane of the toll
plaza, spun out of control, though the details of how it did so
are disputed. Wharton’s truck struck the right rear of Perez’s
car. Perez’s vehicle came to rest against the median wall.
Wharton stopped her truck, and State Trooper Stephen Kenny
responded to the scene.
   The parties dispute exactly how Perez’s vehicle spun out,
and whether, therefore, Wharton reacted appropriately. The
parties also dispute the proper driving speed given the
weather conditions. Plaintiffs say that Perez’s vehicle hit a
patch of black ice within its lane, swerved, then returned to
the original lane of travel in which Wharton was following
Perez. He testified he was driving 15 to 30 miles per hour,
No. 19‐2984                                                  3

about the speed of traffic. According to plaintiffs, Wharton
was driving too fast for conditions, at or slightly above the
posted speed limit, and therefore could not slow down
enough to avoid colliding with Perez.
    Defendants tell a different story. Wharton says that she
saw Perez spin out and that his vehicle moved from the right
lane all the way to the left side of the highway, so she began
to slow down. But after Perez came to a stop on the left side
of the highway, he began unexpectedly to cut all the way
across to the right side of the highway again. Because of this
unusual driving behavior, Wharton says, she was unable to
avoid Perez despite her best efforts to brake. Wharton testified
that she could not remember how fast she was traveling be‐
fore beginning to brake, but that she had downshifted to third
or fourth gear by the time of impact, so that her truck would
have been going 10 to 15 miles per hour. The parties also dis‐
pute further details of Wharton’s driving that are not relevant
to our decision here.
II. Procedural Background and Jurisdiction
    Plaintiffs Moses and Dee Perez filed their suit in the Cir‐
cuit Court of Cook County (Illinois) on January 17, 2017, nam‐
ing both Kiara Wharton and K & B Transportation, Inc. as de‐
fendants. (Mrs. Perez asserts a claim for loss of consortium.)
Defendants removed the suit to federal court based on diver‐
sity of citizenship under 28 U.S.C. § 1332(a)(1). The Perezes
did not move to remand under 28 U.S.C. § 1447(c). After dis‐
covery, Wharton and K & B Transportation moved for sum‐
mary judgment, and the district court granted their motion,
entering final judgment for defendants. The Perezes appeal
that judgment.
4                                                    No. 19‐2984

    On appeal, plaintiffs have challenged federal jurisdiction.
The amount in controversy exceeds $75,000, the Perezes are
citizens of Illinois, and K & B is a citizen of Iowa (state of in‐
corporation) and Nebraska (principal place of business). Ju‐
risdiction under § 1332(a)(1) therefore turns on the citizenship
of defendant Wharton at the time of filing and removal. See
Grupo Dataflux v. Atlas Global Grp., L.P., 

, 570–71
(2004); Chase v. Shop ‘N Save Warehouse Foods, Inc., 

,
427 (7th Cir. 1997).
     Wharton says she is a citizen of Texas, making diversity
complete. Plaintiffs say she has not proven that, so that com‐
plete diversity is lacking. We have held that a “citizen of the
United States who is not also a citizen of one of the United
States may not maintain suit” under § 1332(a)(1). Sadat v. Mer‐
tes, 

, 1180 (7th Cir. 1980). Because the issue gov‐
erns subject‐matter jurisdiction, it could be raised for the first
time on appeal. Grupo 

. We directed
the parties to brief the issue.
   Wharton is a long‐haul truck driver who spends the vast
majority of her time on the road. She currently has no resi‐
dence of her own. Her most recent residence was an apart‐
ment she rented in Texas, but before the Perez accident she
had given that up, started receiving her mail at a post office
box, and begun staying with a family member in Texas when
she was not on the road.
    Plaintiffs argue that these facts rendered Wharton “state‐
less” so that defendants failed to support diversity jurisdic‐
tion. Plaintiffs also point to defendants’ failure to introduce
other evidence tying Wharton to Texas, such as real estate
ownership, payment of state taxes, or voting in Texas. Whar‐
ton has a Texas commercial driver’s license, and the State of
No. 19‐2984                                                     5

Texas requires applicants to provide several documents
demonstrating residency. Remarkably, though, plaintiffs ar‐
gue that “there is no evidence that Wharton actually did any
of those things required.” In other words, plaintiffs imply
without any proof that Wharton and/or an employee of the
State of Texas committed fraud in issuing Wharton’s commer‐
cial driver’s license. Without evidence to the contrary, we pre‐
sume that Wharton and the state employees who issued her
license acted in good faith and complied with Texas law. See,
e.g., Promega Corp. v. Novagen, Inc., 

, 1068
(W.D. Wis. 1997).
    Wharton contends that she established her domicile and
citizenship in Texas, has never subsequently established a
domicile in another state, and is still a citizen of Texas because
she intends to continue her current living arrangements there
indefinitely. See Mitchell v. United States, 

, 353
(1874) (“A domicile once acquired is presumed to continue
until it is shown to have been changed. Where a change of
domicile is alleged the burden of proving it rests upon the
person making the allegation. To constitute the new domicile
two things are indispensable: First, residence in the new lo‐
cality; and, second, the intention to remain there…. Mere ab‐
sence from a fixed home, however long continued, cannot
work the change.”).
   State residence is not necessarily the same as citizenship,
but we are satisfied that Wharton established a residence and
domicile and thus citizenship in Texas, and there is no evi‐
dence she has given up that citizenship. Wharton did not give
up her Texas residence and citizenship simply because her
work frequently takes her away from Texas and she has ar‐
ranged her affairs accordingly. Most important, no evidence
6                                                   No. 19‐2984

shows that Wharton established a domicile and citizenship in
any other state after she established a domicile in Texas. Di‐
versity of citizenship is complete, so subject‐matter jurisdic‐
tion is safe.
III. Summary Judgment on Negligence
    We review a grant of summary judgment de novo, draw‐
ing all reasonable inferences in favor of the non‐moving par‐
ties—here, plaintiffs Moses and Dee Perez. Lewis v. CITGO Pe‐
troleum Corp., 

, 702 (7th Cir. 2009). The plaintiffs
challenge the district court’s exclusion of their expert testi‐
mony and argue that they would have defeated summary
judgment if that evidence had been considered. We affirm the
district court’s exclusion of plaintiffs’ experts but find that
summary judgment was still improper. Applying Illinois law,
a reasonable jury could find that Wharton was negligent
based on the remaining record.
    A. Exclusion of Plaintiffs’ Experts
     We apply two layers of review to a district court’s decision
to exclude expert evidence under Federal Rule of Evidence
702. First, we review de novo a district court’s application of
the legal framework. Second, if the court applied the correct
legal analysis, we review its decision to admit or exclude ex‐
pert testimony for abuse of discretion. C.W. v. Textron, Inc.,

, 835 (7th Cir. 2015), discussing Rule 702 and
Daubert v. Merrell Dow Pharm., Inc., 

(1993). Plain‐
tiffs imply that it was improper for the district court to ana‐
lyze the admissibility of their expert evidence sua sponte,
without adversarial briefing. Defendants raised the issue in
an irregular way, in their sur‐reply on their motion for sum‐
mary judgment. The procedural irregularity does not affect
No. 19‐2984                                                    7

our decision here. A district court is entitled to rule on expert
admissibility sua sponte. See 

, citing
Kirstein v. Parks Corp., 

, 1067 (7th Cir. 1998);
O’Conner v. Commonwealth Edison Co., 

, 1094, 1107
(7th Cir. 1994). As long as the district court has given the par‐
ties an opportunity to be heard and applies the correct legal
framework under Rule 702, we are satisfied. See Gopalratnam
v. Hewlett‐Packard Co., 

, 782 (7th Cir. 2017).
     Before the district court, defendants K & B and Wharton
argued that the opinions of plaintiffs’ experts Mike DiTallo
and Adam Grill were speculative conclusions not based on
the facts of the case. Citing Federal Rule of Evidence 702,
which requires that the expert testimony be “based on suffi‐
cient facts or data” and “the product of reliable principles and
methods,” the district court agreed. In particular, the district
court was concerned that Grill’s report cited barely any case‐
specific evidence and failed to explain the method he used,
and that when he was asked about these same issues at his
deposition, he did not provide any further detail. We find no
abuse of discretion here; the district court clearly applied Rule
702 and excluded Grill’s report on the basis of specific, iden‐
tifiable problems with regard to relevant factors.
    The district court’s exclusion of the DiTallo report is a
closer call, but we find no abuse of discretion. DiTallo cau‐
tioned that “there is not enough data to perform a detailed
crash reconstruction in this matter,” such that he could not
say for certain whether the accident happened as Perez testi‐
fied it did. Based on the limited data available to him, though,
DiTallo opined that Perez’s version of events was possible but
Wharton’s was not physically possible. In particular, he relied
8                                                    No. 19‐2984

on photographic evidence of the site of impact on Perez’s ve‐
hicle to conclude that Perez could not have been coming from
the left shoulder at the time of the collision. In DiTallo’s view,
the site of impact, the right rear of the car, is consistent with
Perez’s version of events but not Wharton’s (in which the trac‐
tor‐trailer would have hit the car’s side).
    Plaintiffs argue on appeal that DiTallo’s limited conclu‐
sions were appropriate and reliable in relation to the limited
evidence available to him. Though the district court was not
specific in its reason for excluding DiTallo’s report, it appears
that the court found it too indeterminate and, as the court
wrote, not “sufficiently grounded in the facts of this case,” de‐
spite its modest conclusions. On abuse‐of‐discretion review,
we cannot overturn this ruling. Nonetheless, genuine issues
of material fact remain even after the exclusion of Grill’s and
DiTallo’s reports.
    B. A Juryʹs Ability to Infer Negligence
    After exclusion of plaintiffs’ experts, the plaintiffs’ case
rests on the testimony of Wharton, Perez, and another driver
who witnessed the collision; the trooper’s crash report; and
photographs of the damage to both vehicles. This record
raises genuine issues of material fact as to whether Wharton
was driving at a safe speed given the treacherous weather
conditions. Accordingly, summary judgment was inappropri‐
ate.
   First, the record presents the trier of fact with two plausi‐
ble and conflicting versions of how Perez’s car spun out of
control. Without conclusive expert evidence, this is a classic
jury question in which Wharton’s credibility must be weighed
against Perez’s. See generally, e.g., Anderson v. Liberty Lobby,
No. 19‐2984                                                       9

Inc., 

, 255 (1986) (“Credibility determinations, the
weighing of the evidence, and the drawing of legitimate in‐
ferences from the facts are jury functions, not those of a judge,
whether he is ruling on a motion for summary judgment or
for a directed verdict.”).
    Second, our precedents have long recognized that “it is the
general rule in Illinois that it is negligence as a matter of law
to drive an automobile at such a rate of speed that it cannot
be stopped in time to avoid a collision with an object discern‐
ible within the driver’s length of vision ahead of him.” Carter
v. Williams, 

, 193–94 (7th Cir. 1966). (It appears
that there was only about one truck length between Perez’s
and Wharton’s vehicles at the moment when Perez began to
spin.) Given the icy conditions, mere compliance with the
posted speed limit in this incident is not necessarily enough
to avoid liability. See 625 ILCS 5/11‐601 (drivers have a duty
to decrease their speed under hazardous weather conditions).
The appropriate speed under the circumstances is a fact‐in‐
tensive question, highly contested by both sides, and the kind
of reasonableness determination that is best suited for a jury.
See, e.g., Surdyk v. Indiana Harbor Belt R. Co., 

, 797
(7th Cir. 1945) (“It is well established law in Illinois, as well as
in other jurisdictions, needing no citation of authorities, that
human conduct must be judged by human standards; that
negligence does not become a question of law alone, unless
the acts constituting it are of such a character that all reason‐
able men would concur in pronouncing them so.”). The dis‐
trict court relied on Wharton’s testimony as to her speed at
impact. The more critical inquiry is how fast Wharton was go‐
ing before she began braking in response to Perez’s spin, and
whether this speed and her following distance were safe un‐
der the circumstances.
10                                                  No. 19‐2984

    The record is not clear on Wharton’s pre‐braking speed,
again pitting Wharton’s recollections against Perez’s in a cred‐
ibility contest that is more appropriate for a jury. As to her
pre‐impact speed, Wharton testified, “I’m not for sure, but I
know I wasn’t going faster than 60.” Immediately before the
accident, Wharton’s truck was in tenth gear, in which it can
travel as fast as 64 miles per hour. Perez testified only that he
was keeping pace with traffic and that he estimated traffic to
be moving between 15 and 30 miles per hour due to condi‐
tions. He estimated that three seconds elapsed between his
vehicle losing traction and the collision.
   Third, though “no presumption of negligence arises merely
from the fact of a rear end collision,” we have long recognized
that a jury may reasonably infer negligence under Illinois law in
such circumstances. Zink v. Radewald, 

, 255 (7th
Cir. 1966) (emphasis added). Trooper Kenny’s report and the
photographic evidence are clear on this point: Wharton’s
truck struck Perez’s vehicle on the right rear. That fact does
not show conclusively that she was not driving with ordinary
care under the circumstances (i.e., the record on this point
does not support summary judgment for either side), but it
could support a jury verdict in Perez’s favor.
   The judgment of the district court is REVERSED and the
case is REMANDED for trial.