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., 157 F.3d 1106, 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 hertruck, 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., 541 U.S. 567, 570–71

(2004); Chase v. Shop ‘N Save Warehouse Foods, Inc., 110 F.3d 424,

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, 615 F.2d 1176, 1180 (7th Cir. 1980). Because the issue gov‐

erns subject‐matter jurisdiction, it could be raised for the first

time on appeal. Grupo Dataflux, 541 U.S. at 571. 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., 6 F. Supp. 2d 1037, 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, 88 U.S. 350, 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., 561 F.3d 698, 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.,

807 F.3d 827, 835 (7th Cir. 2015), discussing Rule 702 and

Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579 (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 Lewis, 561 F.3d at 704, citing

Kirstein v. Parks Corp., 159 F.3d 1065, 1067 (7th Cir. 1998);

O’Conner v. Commonwealth Edison Co., 13 F.3d 1090, 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., 877 F.3d 771, 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., 477 U.S. 242, 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, 361 F.2d 189, 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., 148 F.2d 795, 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, 369 F.2d 253, 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.