Thomas v. Uzoka (Tex.App.- Houston [14th Dist.] May 28, 2009)(Sullivan) (car wreck liability, failure
to wear seatbelt as
negligence per se, proportionate resonsibility)
AFFIRMED: Opinion by Justice Sullivan
Before Justices Brock Yates, Hudson and Sullivan
14-08-00182-CV Lakeisha Thomas v. Ugochi Uzoka
Appeal from 125th District Court of Harris County
Trial Court Judge: JOHN A. COSELLI
Trial Court Cause No. 2006-22678


This appeal arises from a jury verdict in favor of appellee, Ugochi Uzoka (“Ugochi"), whose husband
Onyebu Christopher Ozuka (“Chris") died in a head-on automobile collision.  The driver of the other
vehicle involved in the accident, appellant Lakeisha Thomas ("Thomas"), pleaded guilty to criminal
charges arising from the accident but now brings four issues to challenge the jury's verdict in this
corresponding civil action.  First, she contends the trial court should have instructed the jury that
Chris's non-use of a seat belt amounted to negligence per se.  Second, she claims that the expert
opinions of the two investigating police officers are scientifically unreliable and should have been
excluded.  Third, she challenges the factual and legal sufficiency of the evidence supporting the
jury's findings that she was negligent and that her conduct was ninety-eight percent responsible for
Chris's death.  Fourth, she argues that the damages awarded by the jury are excessive.  We find
no merit in these issues.  Therefore, we affirm the judgment.


The automobile accident occurred on May 14, 2004.  That afternoon, Chris, a taxi-cab driver with
Yellow Cab, was proceeding south on Elysian, a four-lane road that uses an eight-inch-high
concrete median to divide the two northbound and two southbound lanes.  Thomas was driving in
the opposite direction, northbound, in a Nissan pickup truck.  Allegedly, Thomas's truck came over
the concrete median into oncoming traffic, causing a head-on collision with Chris's taxi.  Chris, who
was not wearing a seat belt, died at the scene from a blunt-force impact to the chest.  Thomas was
taken to the hospital.

The accident was investigated by the Houston Police Department, and Thomas was charged with,
and pleaded guilty to, criminally negligent homicide.  She also stipulated to the truth of the State's
allegations that she “unlawfully . . . cause[d] the death of Onyebu [Chris] Uzoka . . . by criminal
negligence, namely by failing to control speed, failing to maintain a single lane of traffic and
exceeding the posted speed limit."[1]

Chris's surviving widow, Ugochi Uzoka, sued Thomas for wrongful death.  She alleged that Thomas
caused the collision by negligently swerving into oncoming traffic.  She further accused Thomas of
speeding.  Thomas denied both allegations, instead claiming that Chris's taxi had crossed the
median.  She also asserted that, by failing to wear his seat belt, Chris was negligent.

The case proceeded to a jury trial in October 2007.  Ugochi produced the expert testimony of two
officers with the Houston Police Department, both of whom supported Ugochi's version of the facts.  
Officer Douglas Ertons (“Ertons"), who conducted the accident investigation, opined that Thomas's
vehicle caused the impact by swerving in front of Chris's taxi.  Officer Rolando Saenz (“Saenz"), an
expert in the field of accident reconstruction, then testified that, according to his calculations,
Thomas was driving sixty-eight miles per hour at the time of the collision.  The posted speed limit
was forty-five miles per hour.  Under cross-examination, Thomas admitted that, arising out of this
event, she pleaded guilty to a charge of criminally negligent homicide and that she stipulated to the
State's specific allegations that she was speeding and that she failed to maintain a single lane of

Over Ugochi's objection, the trial court submitted Chris's comparative negligence to the jury and
permitted Thomas to argue that the failure to wear a seat belt amounted to negligence.  However,
the court rejected a proposed instruction, requested by Thomas, indicating that the non-use of a
seat belt constitutes negligence per se.

In its verdict, the jury found both drivers' negligence proximately caused Chris's death.  The jury
apportioned proportionate responsibility at ninety-eight percent for Thomas and two percent for
Chris.  To compensate Ugochi for past and future pecuniary loss, mental anguish, and loss of
companionship and society, the jury awarded $810,000 in damages.  Thomas has timely appealed
the judgment.

Appellant's second issue, which we address first, deals with Chris's failure to wear a seat belt, in
violation of section 545.413 of the Texas Transportation Code.  See Tex. Transp. Code Ann. §
545.413(a) (Vernon Supp. 2008).  Thomas contends that Chris's non-use of a safety belt
amounted to negligence per se because (1) Chris was in the class of persons that section 545.413
(a) is designed to protect, and (2) his injury was of a type that the statute was intended to prevent.  
See Perry v. S.N., 973 S.W.2d 301, 305 (Tex. 1998).  Therefore, Thomas asked the trial court to
submit the following jury instruction:  “The law requires an adult to wear a safety belt while in the
front seat of a vehicle during its operation.  A failure to comply with this law is negligence in itself."

The trial court refused the requested instruction but submitted Chris's comparative negligence
under a broad-form question asking whether the negligence of either party proximately caused
Chris's death.  Although the jury found Chris negligent, Thomas still appeals the omission of the
requested negligence per se instruction.  However, appellant has not shown that the omission
probably caused the rendition of an improper judgment.  Therefore, we will overrule her second

A.        Standard of Review

A trial court must submit to the jury any instructions that are proper and necessary to enable the
jury to render a verdict.  Tex. R. Civ. P. 277.  An instruction is proper if it might assist the jury in
answering the submitted questions, correctly states the law,[2] and enjoys support in the pleadings
and evidence.  Rigdon Marine Corp. v. Roberts, 270 S.W.3d 220, 228 (Tex. App.- Texarkana 2008,
pet. denied).  However, the jury should not be burdened with surplus instructions, even those that
accurately state the law.  Arocha v. State Farm Mut. Auto. Ins. Co., 203 S.W.3d 443, 445 (Tex. App.
- Houston [14th Dist.] 2006, no pet.).

A trial court has considerable discretion to submit necessary and proper jury instructions.  See id.;
Wal-Mart Stores, Inc. v. Middleton, 982 S.W.2d 468, 470 (Tex. App.- San Antonio 1998, pet.
denied).  Therefore, we review a trial court's decision to refuse a particular instruction under an
abuse of discretion standard.  Shupe v. Lingafelter, 192 S.W.3d 577, 579 (Tex. 2006).  When a
trial court refuses to submit a requested instruction on an issue raised by the pleadings and
evidence, we are to determine whether the instruction was reasonably necessary to enable the jury
to render a proper verdict.  Id.  If so, the refusal to submit a requested instruction will constitute
reversible error only if the omission probably caused the rendition of an improper judgment.  Id.

B.        Harm Analysis

We open our discussion with a brief overview of negligence per se and, when  submitted, its effect
on the jury charge.  Generally, negligence per se is a common-law tort concept in which a person's
expected standard of conduct is defined by a statute instead of the reasonably-prudent-person test
usually found in Apure" common-law negligence claims.  See Smith v. Merritt, 940 S.W.2d 602, 607
(Tex. 1997).  When negligence per se is submitted, the jury is not asked to decide whether the
person acted as a reasonably prudent person would have acted under the same or similar
circumstances, because the statute itself identifies the appropriate standard of conduct as a matter
of law.  Durham v. Zarcades, 270 S.W.3d 708, 718 (Tex. App.- Fort Worth 2008, no pet.); Goode v.
Bauer, 109 S.W.3d 788, 791 (Tex. App.- Corpus Christi 2003, pet. denied) ("The effect of declaring
conduct as negligence per se is that the conduct constitutes negligence as a matter of law.").  
Instead, unless an excuse for the statutory violation is proffered, the jury need decide only (1)
whether the statute was violated and, if so, (2) whether the statutory violation was a proximate
cause of the injury.  Carter v. William Sommerville & Son, Inc., 584 S.W.2d 274, 278 (Tex. 1979);
Durham, 270 S.W.3d at 719.

Negligence per se is not a separate cause of action that exists independently of a common-law
negligence cause of action.  Zavala v. Trujillo, 883 S.W.2d 242, 246 (Tex. App.- El Paso 1994, writ
denied).  Rather, negligence per se is merely one method of proving a breach of duty, a requisite
element of any negligence cause of action.  Reynolds v. Murphy, 188 S.W.3d 252, 267 n.20 (Tex.
App.- Fort Worth 2006, pet. denied) (quoting Zavala, 883 S.W.2d at 246).  Here, while that specific
option was not available to Thomas,  the trial court granted her request to submit Chris's non-use
of a seat belt through a broad-form negligence question and, in fact, the jury found Chris
negligent.  Thus, because the requested instruction would not have produced a different outcome,
we cannot conclude that Thomas was harmed by the omission of the requested instruction.[3]  See
Mieth v. Ranchquest, Inc., 177 S.W.3d 296, 305 (Tex. App.- Houston [1st Dist.] 2005, no pet.) (A[T]
he trial court abused its discretion by refusing to submit an instruction on negligence per se.  
However, because the jury found [the defendant] negligent under the common-law definition, the
trial court's error was harmless.").[4]

Thomas responds that she was harmed by the omission because, had the jury known that the non-
use of a safety belt is prohibited by statute, it might have assigned a higher percentage of
responsibility to Chris, thereby reducing the amount of Thomas's liability for the damages awarded.  
See Tex. Civ. Prac. & Rem. Code Ann. § 33.012(a) (Vernon 2008). However, as this Court noted in
Patterson v. Landua, a negligence per se instruction does not affect the jury's apportionment of
responsibility among various causes of a plaintiff's injuries.  No. 14-97-00372-CV, 1998 WL
322693, at *4 (Tex. App.- Houston [14th Dist.] June 18, 1998, pet. denied) (not designated for
publication).  Negligence per se may substitute for proof that a legal duty was breached; however, it
does not compel the jury to conclude that the statutory violation was a proximate cause of the
damages claimed.  See Carter, 584 S.W.2d at 278 (indicating that, even when negligence per se is
submitted, a jury must still decide whether statutory violation was a proximate cause of the claimed
damages); Durham, 270 S.W.3d at 719.

Because apportionment of responsibility is a subsidiary question that goes to causation, it is
similarly unaffected by a negligence per se instruction.  See Tex. Civ. Prac. & Rem. Code Ann. §
33.003(a) (Vernon 2008) (“The trier of fact . . . shall determine the percentage of responsibility . . .
with respect to each person's causing or contributing to cause . . . the harm for which recovery of
damages is sought[.]") (emphasis added); id. § 33.011(4) (defining “percentage of responsibility"
as percentage attributed to each party “with respect to causing or contributing to cause" claimed
damages).  Therefore, it cannot be said that inclusion of a negligence per se instruction would
have altered the jury's decision to assign to Thomas ninety-eight percent of the responsibility for
causing Chris's death.  See Shupe, 192 S.W.3d at 580.  Accordingly, Thomas has not shown that
the absence of the requested instruction probably caused the rendition of an improper verdict.  
See Tex. R. App. P. 44.1(a)(1).

Thomas reminds us that she presented two factual bases for the jury to find Chris negligent: failing
to wear a seat belt and driving while distracted.  She contends we cannot determine on which
ground the jury found Chris negligent and suggests that, in the absence of a negligence per se
instruction, the jury might have rejected her seat-belt theory and instead faulted Chris under her
distracted-driver allegation.[5]  She therefore argues that the omission of the requested instruction
prevented her from properly presenting this appeal, see Tex. R. App. P. 44.1(a)(2), and asks us to
presume harm under Crown Life Insurance Co. v. Casteel.  22 S.W.3d 378 (Tex. 2000).  We
decline to extend Casteel under these circumstances.

In Casteel, the Texas Supreme Court held that, when a jury bases a finding of liability on one broad-
form question that commingles invalid theories of liability with valid theories, an appellate court
often cannot determine the effect of the error and therefore should presume harm.  See id. at 388.  
It reasoned that, when a broad-form submission contains both valid and invalid legal theories, the
jury may have found the defendant liable solely on a legal theory that should not have been
submitted.  See id. at 389.  Thus, the defendant may have suffered harm from the improper
submission but cannot prove it.  See id. at 388.

However, in this case Thomas has not shown even a possibility of harm inasmuch as she received
the jury finding she desired, that is, that Chris was negligent, and the requested instruction does
not affect the jury's apportionment of responsibility among the parties.   See Shupe, 192 S.W.3d at
580. Moreover, the Texas Supreme Court has expressly declined to extend Casteel to cases like
this one.  See Bed, Bath & Beyond, Inc. v. Urista, 211 S.W.3d 753, 757 (Tex. 2006).

Therefore, Thomas has not shown that the alleged error probably prevented her from presenting
her appeal.  See Tex. R. App. P. 44.1(a)(2).  Accordingly, we overrule appellant's second issue.

Appellant's third and fourth issues are related, and we address them together.  In her fourth issue,
Thomas contends the evidence is legally and factually insufficient to support the jury's findings with
respect to negligence, proximate cause, and proportionate responsibility.  This sufficiency claim is
premised upon her argument - contained in both her third and fourth issues - that the opinions
offered by Ertons and Saenz, while supportive of the verdict, constitute "no evidence" because
such testimony was unreliable and inadmissible.  Thus, before we address Thomas's sufficiency
complaint, we must review her challenge to the reliability of both officers' expert testimony.  See
Transcon. Ins. Co. v. Crump, 274 S.W.3d 86, 96 (Tex. App.- Houston [14th Dist.] 2008, pet. filed).

A.        Reliability of Officers' Opinions

Generally, courts review a challenge to the admission of expert testimony under an abuse of
discretion standard.  See Taylor v. Am. Fabritech, Inc., 132 S.W.3d 613, 618 (Tex. App.- Houston
[14th Dist.] 2004, pet. denied).  However, when a trial court admits expert testimony that is
challenged on appeal as constituting Ano evidence," as here, we review the reliability of the expert
testimony using a de novo standard of review.  Transcon. Ins. Co., 274 S.W.3d at 96; Goodyear
Tire & Rubber Co. v. Rios, 143 S.W.3d 107, 113 (Tex. App.- San Antonio 2004, pet. denied).

The trial court is charged with ensuring that expert testimony is based upon a reliable foundation
and is relevant to the issues in the case.  Gammill v. Jack Williams Chevrolet, Inc., 972 S.W.2d 713,
728 (Tex. 1998).  In deciding the reliability of an expert's methodology and the underlying data, the
trial court may consider several non-exclusive factors, including (1) the extent to which the expert's
theory has been or could be tested; (2) the extent to which his technique relies upon subjective
interpretation; (3) whether his technique has been subjected to peer review and/or publication; (4)
the potential error rate for the technique; (5) whether the expert's underlying theories or techniques
have been generally accepted as valid by the relevant scientific community; and (6) the non-judicial
uses that have been made of the theory or technique.  See E.I. du Pont de Nemours & Co. v.
Robinson, 923 S.W.2d 549, 557 (Tex. 1995).  In addition, a trial court may give weight to the
expert's skill and experience when appropriate to do so.  See Gammill, 972 S.W.2d at 726.  If there
is an analytical gap between the expert's conclusions and the underlying data upon which he relies,
his expert testimony may be unreliable and inadmissible.  See id.

The expert testimony Thomas seeks to exclude came from Ertons and Saenz, and fall into two
rough categories.  First, both officers testified, on the strength of physical evidence collected at the
accident scene, that the collision occurred because Thomas's vehicle cut across the concrete
median into oncoming traffic.  Second, Saenz determined, using foundational data and
measurements gathered by Ertons, that Thomas was speeding at the time of the collision.  Hoping
to exclude these opinions, Thomas argues that Saenz's opinions were drawn from unreliable
foundational data provided by Ertons.

1.         Crossing the Median

Generally, Thomas insists that Ertons failed to exclude alternative causes for the collision, and that
an analytical gap therefore renders his opinions unreliable.  See Robinson, 923 S.W.2d at
558B59.  Specifically, during the course of his investigation, Ertons interviewed Thomas, who
denied that her truck transversed the concrete median.  Instead, she claimed that she was driving
in her own lane and saw Chris's vehicle driving in her lane, but she could not avoid a collision.  
After examining the accident scene, Ertons rejected Thomas's story and concluded that she, not
Chris, crossed the median and caused the accident.

Thomas argues that, before Ertons could offer testimony as an expert, he was obligated to
consider and rule out other possible causes for the collision.[6]  See id. at 559 (holding that
expert's failure to rule out other causes of damage rendered his opinion little more than
speculation); Emmett Props., Inc. v. Halliburton Energy Servs., Inc., 167 S.W.3d 365, 373B74 (Tex.
App.- Houston [14th Dist.] 2005, pet. denied).  While we agree with that general proposition, the
record indicates that Ertons did not overlook Thomas's version of the facts.  Instead, he decided
that her claim was inconsistent with, and contradicted by, the physical evidence he found at the
accident scene.

For example, Ertons found fresh gouge marks in the median south of the impact scene - the
direction from which Thomas was traveling - but not north.[7]  This finding supported his opinion
that, as Thomas's northbound vehicle crossed the median, the underside of her truck scratched
the concrete median, leaving behind gouge marks and powdery concrete residue.

Next, Thomas complains that Ertons failed to interview any witnesses to the collision.  Of course,
this contention presupposes that somebody in fact witnessed the accident.  However, nobody who
claimed to have seen the impact came forward; in addition, Ertons suggested that the presence of
witnesses would have been unlikely because the collision occurred in a rather remote, unpopulated
location that he described as Athe middle of nowhere."

Therefore, on the record presented, we hold that the trial court properly admitted Ertons's expert
testimony as to the cause of the automobile collision.  Next, we address Thomas's objection to
Saenz's opinions about the vehicle speeds at the time of impact.

2.         Vehicle Speeds

Thomas presents two basic objections to the reliability of Saenz's expert testimony.  First, she
contends that his opinions depend upon unreliable measurements provided by Ertons.  Second,
she argues that Saenz used flawed methodology to draw expert conclusions from those
measurements.  As such, she concludes the trial court should have excluded Saenz's opinions
about the respective speeds of both vehicles at impact.  See Ford Motor Co. v. Ledesma, 242 S.W.
3d 32, 39 (Tex. 2007).

a.         Reliability of Underlying Data

We begin with a look at Ertons' measurements, which were transcribed from his notes into a scale
diagram that Saenz used in calculating vehicular speeds.  Thomas presents three objections to the
reliability of these measurements.  First, she claims that the device Ertons employed to take those
measurements - a roller wheel - is less accurate than a “total station device."  However, at the time
of the accident, the Houston Police Department did not own a total station device, an instrument
that Ertons described as only Avery modestly more accurate" than a roller wheel.  Moreover, Ertons
testified that a roller wheel produces reliable measurements, and further confirmed that the use of
a roller wheel is generally accepted as a valid instrument used in taking measurements in the field
of accident investigation.  See Robinson,  923 S.W.2d at 557.

Second, Thomas contends that, because Ertons disposed of his original field notes, the
measurements listed in the scale diagram cannot be trusted because the possibility exists that
Ertons might have incorrectly transcribed the figures from his notes.  In response, Ertons confirmed
that he correctly copied all of the information from his field notes into the offense report, accident
report, and scale diagram.  In addition, had there been some question about the accuracy of his
measurements, Ertons testified that the original figures could be recreated from the accident
photographs through a process called “photogrammetry."  Stated differently, the accuracy of the
measurements could be tested and independently verified.  Therefore, the loss of Ertons's field
notes does not render those measurements unreliable.  See id.

Third, Thomas challenges the use of the scale diagram altogether in rendering calculations about
vehicle speed, because the initial pre-collision location of Chris's taxi on the diagram is entirely
unsupported by any facts or measurements.  She therefore insists that Saenz could not reliably use
the figures listed in the diagram to calculate vehicle speeds.  However, the record indicates that, in
computing vehicle speeds, Saenz ignored Ertons's depiction of the pre-impact location of Chris's
vehicle.  This fact is borne out in the officers' testimony and the scale diagram itself.[8]  Thus, we
cannot conclude that the trial court erred by permitting Saenz to draw conclusions from the
measurements listed in the scale diagram.

b.         Reliability of Opinions Drawn from Data

Saenz reached his opinions about vehicle speed by using a computer program called WinCrash.  
Thomas challenges those opinions on three basis grounds: (1) Saenz was forced to guess at the
total pre-collision weight of each vehicle; (2) the speed calculations were generated using an
incorrect impact-angle analysis; and (3) the WinCrash report contained several errors that
undermine any confidence in the program's computations.  As we address these concerns, we
remain mindful that courts are not to decide whether an expert's conclusions are correct, but
instead whether the analysis he used to reach them is reliable.  See Gammill, 972 S.W.2d at 728.  
That guidance is particularly important here because the record is not well-developed enough to
resolve some of appellant's challenges to the WinCrash report.[9]  See, e.g., Harris County Hosp.
Dist. v. Textac Partners I, 257 S.W.3d 303, 310 (Tex. App.- Houston [14th Dist.] 2008, no pet.)
(expressing reluctance to find error, and sustain appellate point, in light of underdeveloped
appellate record).  Generally, however, Saenz confirmed that his vehicle-speed calculations rely
upon well-known physics and mathematics principles, that the formulas he used are recognized and
verifiable by other experts, and that the software and methodology he employed is reliable, peer-
reviewed, and generally accepted by the accident-reconstruction community.  See Robinson, 923 S.
W.2d at 557.

Thomas's first complaint deals with the estimated pre-collision weights for each vehicle.  
Apparently, WinCrash requires the user to input the total weight of each vehicle before the impact.  
Unfortunately, those exact figures are almost always unavailable after a collision has occurred.  
Therefore, accident reconstruction experts must instead consider estimated vehicle weights.  Here,
for example, the average weight of Thomas's Nissan pickup truck is listed at 2,750 pounds; Chris's
Ford Crown Victoria, by contrast, is said to weigh 3,920 pounds.  Those base figures do not reflect
the weight of vehicles laden with occupants, contents, or vehicle fluids such as gasoline.  
Therefore, Thomas acknowledges that “reconstructionists often have to guess the weights of
vehicle[s] to compensate for debris and fluids that were lost during the crash[.]" However, the crux
of her argument appears to arise from the fact that the accident-reconstruction community has not
established definitive guidelines to be used in determining how many pounds should be added to a
vehicle's base weight to arrive at an estimated pre-collision weight.

Here, as in the usual case, Saenz could not have obtained an exact pre-collision weight for either
vehicle because (1) both drivers were removed from the scene, one to the hospital and the other to
the morgue; (2) debris was strewn all about the road; and (3) vehicle fluids had been splattered on
the ground.  Therefore, as an estimate of pre-collision vehicle weights, Saenz added 200 pounds to
the Nissan's base weight to compensate for Thomas's weight and that of the contents and fluids.  
However, because a taxi typically carries extra equipment not ordinarily found in a passenger
automobile, Saenz added more weightC300 pounds - to the Crown Victoria's base weight.  Thomas
does not specifically challenge these estimated figures, except to complain about the lack of an
industry standard.  We are left with no basis to question Saenz's validity given that both parties
agree that the practice of using estimated pre-collision vehicle weights is generally accepted within
the accident-reconstruction community.  See id.

Apparently, another factor that WinCrash considers in calculating vehicle speeds is the angle at
which the cars collide.  Depending on the angle, WinCrash uses one of two different formulas to
render its computations: a linear-momentum formula and an angular-momentum formula.  When
vehicles collide at an angle of greater than ten degrees, the angular-momentum formula should be
used in lieu of the linear-momentum formula.  Here, Saenz assumed that the vehicles collided at an
impact of twenty-one degrees.  This determination would apparently dictate that WinCrash use the
angular-momentum formula.  Instead, Thomas contends that WinCrash incorrectly used the linear-
momentum formula.

As we attempt to resolve this objection, we note that the record on this point is rather unclear.  
Even if we assume that WinCrash employed the incorrect formula in calculating vehicle speeds, the
record is silent as to the effect of that error on the reliability of the program's conclusions.  An entry
in the HPD records implies that, if anything, WinCrash may have underestimated the speed of
Thomas's vehicle at the point of impact.  In any event, although WinCrash apparently reported a
value using the linear-momentum value, Saenz's testimony suggests that the program also
incorporated the correct angular-momentum formula.[10]  Thus, we cannot conclude from this
underdeveloped record that the trial court was required to exclude Saenz's expert testimony that
Thomas was driving at least sixty-eight miles per hour.

Finally, Thomas contends that the WinCrash computations are unreliable because the program
reported several error messages that should have undermined the trial court's confidence in the
validity of its calculations.  However, Saenz explained that each of the error messages was
expected and could be explained by the physical evidence found at the accident scene.  For
example, WinCrash assumes that vehicles collide on a flat, level surface and that, after impact,
there are no obstacles that might impede the vehicles' movement to their final resting spot.  
However, in this case, each vehicle met an obstacle that slowed or stopped its lateral movement
after the accident.  Because Thomas's truck was straddling the median, it did not fully rotate as
would be expected on a flat surface because the median itself slowed that rotation.  Similarly, the
lateral movement of Chris's taxi was stopped by the presence of the guardrail on the side of the
road.  However, because WinCrash did not know about the existence of the median or guardrail, it
predicted more rotation by Thomas's truck and greater lateral movement by Chris's taxi than
actually occurred.  Therefore, the program generated several error messages indicating that, if the
collision occurred as indicated, the vehicles did not behave post-impact as the computer model
predicted they would.

In response, Saenz testified that it is generally accepted in the accident-reconstruction community
to rely upon WinCrash results when the program's error messages can be explained by the
physical evidence.  See Robinson, 923 S.W.2d at 557.  Moreover, he indicated that, while the error
messages might result in an understatement of the vehicles' lateral momentum speed, they would
not affect the equivalent barrier speed, which was the calculation that Saenz quoted to the jury.  
Stated differently, the error messages had nothing to do with Saenz's equivalent-barrier-speed

Therefore, we conclude that the trial court properly admitted the expert testimony of both
investigating officers, because their opinions were based on a reliable foundation.  Accordingly, we
overrule appellant's third issue.

B.        Legal and Factual Sufficiency of Evidence of Negligence, Proximate Cause, and
Proportionate Responsibility

In her fourth issue, Thomas challenges the [...]

Affirmed and Memorandum Opinion filed May 21, 2009.