Fourth Court of Appeals

San Antonio, Texas

OPINION

No. 04-21-00570-CR

Rueben Justin TREJO,

Appellant

v.

The STATE of Texas,

Appellee

From the 144th Judicial District Court, Bexar County, Texas

Trial Court No. 2019-CR-9333

Honorable Michael E. Mery, Judge Presiding

Opinion by: Patricia O. Alvarez, Justice

Sitting: Patricia O. Alvarez, Justice

Irene Rios, Justice

Lori I. Valenzuela, Justice

Delivered and Filed: December 6, 2023

AFFIRMED

A jury convicted Appellant Ruben Justin Trejo of criminally negligent homicide and 

assault after he caused a fatal collision with another driver. It sentenced him to two years’ jail. In 

three issues, Trejo complains that the trial court erred in overruling his objections to the admission 

of (1) a certified copy of his driving record during the punishment phase of trial, (2) expert 

testimony about data retrieved from his vehicle’s data recorder, and (3) expert testimony that failed 

to satisfy his Sixth Amendment right to confront adverse witnesses. We affirm.
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BACKGROUND

Appellant Trejo caused a highspeed head-on collision by driving through an intersection 

against a red light. The crash occurred at night, and, though Trejo’s car was equipped with daytime 

running lights, his headlights were off. His blood-alcohol level was .04. He killed the driver of 

the car he struck and was charged with manslaughter and aggravated assault.

At trial, the State used data from Trejo’s car’s airbag control module in conjunction with 

road evidence at the scene to establish his speed at the time of the crash. State’s expert witness 

Sergeant Windsor testified that he was trained in retrieving the module’s data through a software 

interface to read the results of the car’s sensor inputs. Trejo objected to the admission of Sergeant 

Windsor’s testimony as inadequate under the Sixth Amendment, but the trial court overruled the 

objection. Sergeant Windsor testified that Trejo was driving approximately seventy miles per hour 

in a forty-five mile-per-hour zone upon impact. The jury convicted Trejo of criminally negligent 

homicide and simple assault.

At sentencing the State introduced Trejo’s driving record, which showed that he had

received three previous speeding citations. Trejo objected to the admission of the driving record 

because it was not accompanied by certified judgments of guilt for the citations. But the State 

argued that Trejo’s driving record was admissible as evidence of bad acts and character. The trial 

court overruled Trejo’s objection. The jury sentenced Trejo to two years’ state jail and one year 

in the county jail. Trejo appealed.

ADMISSIBILITY OF DEFENDANT’S DRIVING RECORD DURING THE PUNISHMENT PHASE

A. Parties’ Arguments

In Trejo’s first issue, he argues that the trial court should not have admitted his driving 

record during his punishment-phase trial because it was insufficient to prove his speeding 

convictions beyond a reasonable doubt. The State argues that it was not required to “re-prove” 
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Trejo’s past speeding convictions. It argues that the law only requires the State to prove that the 

driving record admitted during the punishment phase trial belonged to Trejo and that it did.

B. Standard of Review

“A trial court has broad discretion in determining the admissibility of evidence presented 

at the punishment phase of trial.” Schultze v. State, 177 S.W.3d 26, 40 (Tex. App.—Houston [1st 

Dist.] 2005, pet. ref’d) (citing Henderson v. State, 29 S.W.3d 616, 626 (Tex. App.—Houston [1st 

Dist.] 2000, pet. ref’d)). “We will not disturb a trial court’s determination regarding the 

admissibility of relevant evidence unless an abuse of discretion has been shown.” Id. (citing Green 

v. State, 934 S.W.2d 92, 101–02 (Tex. Crim. App. 1996)).

C. Law

At a punishment-phase trial, “evidence may be offered by the state...as to any matter the 

court deems relevant to sentencing, including but not limited to the prior criminal record of the 

defendant, ... his character, ... and, notwithstanding Rules 404 and 405, Texas Rules of Evidence,

any other evidence of an extraneous crime or bad act that is shown beyond a reasonable doubt by 

evidence to have been committed by the defendant or for which he could be held criminally 

responsible, regardless of whether he has previously been charged with or finally convicted of the 

crime or act.” TEX. CODE CRIM. PROC. ANN. art. 37.07; Haley v. State, 173 S.W.3d 510, 515 (Tex. 

Crim. App. 2005). 

The process of proffering evidence to prove an extraneous offense, even when not explicit, 

is referred to as a threshold inquiry. See Flores v. State, 440 S.W.3d 180, 199–200 (Tex. App.—

Houston [14th Dist.] 2013), judgment vacated on other grounds, 427 S.W.3d 399 (Tex. Crim. App. 

2014) (citing Palomo v. State, 352 S.W.3d 87, 94 (Tex. App.—Houston [14th Dist.] 2011, pet. 

ref’d)). This threshold standard requires the State to be able to prove the commission of bad acts 

and extraneous crimes beyond a reasonable doubt and proffer its evidence before the trial court 
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may admit it for the jury’s consideration. See id. (citing Arzaga v. State, 86 S.W.3d 767, 781–82 

(Tex. App.—El Paso 2002, no pet.). 

When the State offers a certified judgment, it satisfies the requirement of proving that the 

extraneous crime was committed. See Cain v. State, 468 S.W.2d 856, 858 (Tex. Crim. App. 1971),

overruled on other grounds by Littles v. State, 726 S.W.2d 26, 32 (Tex. Crim. App. 1984); Gentile 

v. State, 848 S.W.2d 359, 360 (Tex. App.—Austin 1993, no pet.). Without a certified judgment, 

“[t]he trial court may not admit extraneous offense evidence unless the evidence is such that a jury 

could rationally find the defendant criminally responsible for the extraneous offense [beyond a 

reasonable doubt].” Flores, 440 S.W.3d at197 (quoting Palomo v. State, 352 S.W.3d 87, 92 (Tex.

App.—Houston [14th Dist.] 2011, pet. ref’d); accord Davis v. State, 315 S.W.3d 908, 914 (Tex. 

App.—Houston [14th Dist.] 2010), rev’d on other grounds, 349 S.W.3d 517 (Tex. Crim. App. 

2011). “Whether an extraneous offense was established beyond a reasonable doubt, however, is a 

question of fact for the jury rather than a preliminary question of admissibility for the trial court.” 

Davis, 315 S.W.3d at 914 (citing Mitchell v. State, 931 S.W.2d 950, 955 (Tex. Crim. App. 1996)

(plurality opinion)).

With specific regard to the admissibility of a driving record to show evidence of past bad 

acts, the State must proffer more than the driving record alone. See Gentile, 848 S.W.2d at 360; 

accord Tex. Dep’t of Pub. Safety v. Gentry, 386 S.W.2d 758, 760 (Tex. 1965). This is not because 

the State must prove a conviction of an act listed in the driving record, but rather because the 

evidentiary value of the driving record is limited. See Gentile, 848 S.W.2d at 360. Therefore, for

acts listed in a defendant’s driving record to be admissible in the State’s case at punishment, the 

State must be able establish their full relevance to the defendant and his punishment, i.e., that the 

subject matter is relevant to the jury’s assessment, that the act or offense is linked to the defendant, 

and that the offense transpired, to the degree that “a jury could rationally find the defendant 
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criminally responsible.” See Palomo, 352 S.W.3d 87, 91‒92 (citing Davis, 315 S.W.3d at 914); 

accord Smith v. State, 227 S.W.3d 753, 760 (Tex. Crim. App. 2007). Alone, the driving record is 

only conditionally relevant, depending on what the State can (and does) present. See Huddleston 

v. United States, 485 U.S. 681, 690 n.7 (1988) (quoting 21 C. Wright & K. Graham, Federal 

Practice and Procedure § 5054, pp. 269–270 (1977)); Gentile, 848 S.W.2d at 360.

If the State does not proffer or present more than the driving record alone to prove a bad 

act or extraneous offense, it is incumbent upon the defendant to object. See TEX. R. APP. P. 33.1; 

Palomo, 352 S.W.3d at 92; Flores, 440 S.W.3d at 197 (citing Mitchell, 931 S.W.2d at 953–54; 

Davis, 315 S.W.3d at 914). “It is, of course, not the responsibility of the judge sua sponte to insure 

that the foundation evidence is offered; the objector must move to strike the evidence if at the close 

of the trial the offeror has failed to satisfy the condition.” Huddleston, 485 U.S. at 690 n.7. In the 

absence of a trial objection that comports with a defendant’s argument on appeal, the issue on 

appeal is waived. See TEX. R. APP. P. 33.1; Palomo, 352 S.W.3d at 92 (citing Guevara v. State, 

97 S.W.3d 579, 583 (Tex. Crim. App. 2003)). 

D. Analysis

Here, Trejo objected at his punishment-phase trial to the admission of his driving record 

because it was insufficient to prove his prior convictions for speeding. See Gentile, 848 S.W.2d 

at 360. He stated:

Your Honor, they do not have any judgments, certified copies of 

judgments, any type of judgment evidence. All they have is a copy 

of the driving record. And that case1 states that that is insufficient to

present testimony of convictions. 

If there was an incomplete judgment, like if it was missing a 

thumbprint, if it was missing identifiers that were legally sufficient 

by itself, you could couple the two documents together to prove the

sufficiency of that, but just the driving record by itself is legally 

1 Trejo provided unidentified caselaw to the trial court in support of his objection.
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insufficient to prove a conviction for a prior offense. And so we are 

asking that the—any evidence of his convictions for speeding not be 

allowed in front of the jury.

And so I guess we are objecting to—prior to their request for 

admission that that be introduced into evidence.

The State responded that it was not attempting to prove Trejo’s prior convictions for 

speeding, but rather that it was offering Trejo’s driving record merely as evidence of bad acts and 

character. See TEX. CODE CRIM. PROC. ANN. art. 37.07; Haley, 173 S.W.3d at 515. 

So on the driver’s record, if you see in the case that they’re

providing, right in that case they’re charged with DWI third and 

they’re trying to prove up a prior—they are trying to establish the 

prior convictions in order to establish jurisdiction in that case. And 

so they’re saying that that driving record—the certified driving 

record is not sufficient to prove the convictions. But in this case 

we’re simply offering it as—not as an enhancement purpose, not to

enhance his punishment in some way, not to establish jurisdiction. 

It’s simply going to bad acts, character of the defendant,2 which is 

allowed in the punishment phase at this point.

The trial court overruled Trejo’s objection, stating, “Let me see what you intend to 

introduce, please. Your objection is overruled. That will be admitted. Take this back.”3 See

Schultze, 177 S.W.3d at 40. Trejo did not object or respond to the State’s bad acts and character 

argument. See Palomo, 352 S.W.3d at 92. Even when the State offered Trejo’s driving record as 

an exhibit, Trejo made no objection to its use as evidence of prior bad acts or extraneous offenses. 

See TEX. R. APP. P. 33.1. Instead, he reiterated his previous objection and added “improper 

predicate, improper witness to admit this evidence,” which the trial court also overruled.

Trejo now argues that a jury should only be permitted to consider extraneous offenses or 

bad acts at sentencing if they are proven beyond a reasonable doubt. Contra id. (citing Davis, 315 

2 We understand this to mean “character evidence in the form of ... extraneous-offense evidence.” See Sims v. State, 

273 S.W.3d 291, 295 (Tex. Crim. App. 2008) (citing TEX. CODE CRIM. PROC. ANN. art. 37.07). 3 Exhibit 117, a certified copy of Trejo’s driving record.
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S.W.3d at 914; Mitchell, 931 S.W.2d at 954). As stated, it is the jury who decides whether 

extraneous offenses or bad acts are proven beyond a reasonable doubt. See id. (citing Mitchell, 

931 S.W.2d at 953–54). The jury should be instructed not to consider an extraneous offense if the 

evidence does not establish it beyond a reasonable doubt. See Mitchell, 931 S.W.2d at 954. But 

to stop the jury from considering potentially insufficient evidence of prior bad acts after the State 

has closed its case, i.e., evidence that could not establish an extraneous offense beyond a 

reasonable doubt, Trejo would have had to move to strike the inadequate evidence, which he did 

not do. See TEX. R. APP. P. 33.1; Huddleston, 485 U.S. at 690 n.7; Palomo, 352 S.W.3d at 92. We 

conclude that Trejo waived the issue of whether the State could or did present sufficient evidence

in support of its bad acts/extraneous offense evidence. See Palomo, 352 S.W.3d at 92. We also 

conclude that Trejo waived the related issue of whether Trejo’s driving record was properly linked 

to him, since he did not object to the link at trial and, in fact, argued the opposite, i.e., that a driving 

record could be used to link a defendant to a conviction but not to prove the conviction. See TEX.

R. APP. P. 33.1. We overrule Trejo’s first issue.

ADMISSIBILITY OF SERGEANT WINDSOR’S EXPERT TESTIMONY

A. Parties’ Arguments

In his second and third issues, which Trejo has briefed collectively, Trejo argues that the 

trial court erred by allowing Sergeant Windsor to testify to Trejo’s approximate speed at the time 

of the crash because he could not explain the innerworkings of the software he used to read Trejo’s 

car’s collision data. Trejo argues that his Sixth Amendment right to confront adverse witnesses 

was violated as a result. 

The State argues that the trial court acted within its discretion in admitting Sergeant 

Windsor’s expert testimony because it was reliable. The State argues that Trejo’s Sixth 
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Amendment right to confront adverse witnesses was not violated because Sergeant Windsor

generated the data report regarding Trejo’s crash and was available for cross-examination.

B. Standard of Review

“An appellate court reviews a trial court’s admission of evidence and expert testimony for 

an abuse of discretion, i.e., whether the trial court’s ruling was within the zone of reasonable 

disagreement.” Vitela v. State, 649 S.W.3d 649, 656 (Tex. App.—San Antonio 2022, pet. ref’d)

(citing Weatherred v. State, 15 S.W.3d 540, 542 (Tex. Crim. App. 2000)). But we review Sixth 

Amendment questions of law de novo. Boutang v. State, 402 S.W.3d 782, 787 (Tex. App.—San 

Antonio 2013, pet. ref’d) (citing Langham v. State, 305 S.W.3d 568, 576 (Tex. Crim. App. 2010)).

C. Law

1. Admissibility of Expert Testimony Under Rule 702

“A witness who is qualified as an expert by knowledge, skill, experience, training, or 

education may testify in the form of an opinion or otherwise if 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.” TEX.R. EVID. 702; Rhomer v. State, 569 S.W.3d 664, 669 (Tex. Crim. App. 2019); 

Wooten v. State, 267 S.W.3d 289, 297 (Tex. App.—Houston [14th Dist.] 2008, pet. ref’d). But 

the trial court must first decide whether the expert and the proposed testimony satisfy Rule 702

based on the rule’s three constituent parts regarding qualification, reliability, and relevance: “(1) 

The witness qualifies as an expert by reason of his knowledge, skill, experience, training, or 

education; (2) the subject matter of the testimony is an appropriate one for expert testimony; and 

(3) admitting the expert testimony will actually assist the fact-finder in deciding the case.” 

Rhomer, 569 S.W.3d at 669 (quoting Vela v. State, 209 S.W.3d 128, 131 (Tex. Crim. App. 2006)). 

The qualification prong depends, not on whether the proffered expert is the best possible 

witness, but rather, whether the expert’s qualifications would assist the jury in determining an issue 
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of fact, i.e., whether the expert has sufficient background in his area of testimony and whether he 

is a good “fit” for the matter in question. Id. at 669‒70. For example, the accident reconstructionist 

in Rhomer was considered qualified because he was an experienced police officer who 

“investigated at least a thousand vehicular crashes and had testified once as an accident 

reconstruction expert in a case that involved two cars and a pickup truck.” Id. at 667, 671. He had 

attended three courses related to vehicle collisions, learned the basics of crash investigation in an 

intermediate crash investigation course, attended an advanced course at Texas A & M University, 

and took a reconstruction course and courses on accidents involving pedestrians and bicycles. See 

id. He testified that his accident reconstruction course work totaled 501 hours. See id. The 

Rhomer court determined that the reconstructionist’s “qualifications would have assisted the jury 

in determining issues of fact, namely, where and how the collision happened.” Id. at 671.

The reliability requirement may be more or less exacting based on the type of expert 

testimony being introduced, i.e., soft or hard science. See id. at 671 (citing Nenno v. State, 970 

S.W.2d 549, 561 (Tex. Crim. App. 1998), overruled on other grounds by State v. Terrazas, 4 

S.W.3d 720, 727 (Tex. Crim. App. 1999); Kelly v. State, 824 S.W.2d 568, 573 (Tex. Crim. App. 

1992)). In Rhomer, the court concluded that an accident reconstructionist’s testimony was 

admissible under the Nenno standard for soft science where the expert’s opinions were based on 

his training and experience more than on a hard scientific inquiry such as calculating a vehicle’s 

pre-impact speed. See id. at 671; accord Mireles v. State, No. 08-19-00221-CR, 2022 WL 

3572859, at *9 (Tex. App.—El Paso Aug. 19, 2022, pet. ref’d) (mem. op., not designated for 

publication). “The Nenno test asks whether (1) the field of expertise is a legitimate one, (2) the 

subject matter of the expert’s testimony is within the scope of that field, and (3) the expert’s 

testimony properly relies upon and/or utilizes the principles involved in the field.” Id. (citing 

Nenno, 970 S.W.2d at 561). The Rhomer court stated: “(1) the field of accident reconstruction is 
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a legitimate one, (2) the subject matter of [the expert’s] testimony was within the scope of that 

field, and (3) his testimony properly relied upon and utilized the principles involved in the field, 

i.e., examining the physical evidence in the context of the crash site to draw conclusions about the 

location and cause of the crash.” Id. at 672.

Admissibility may also depend on whether the probative value of the proffered expert 

testimony “is substantially outweighed by the danger of unfair prejudice, confusion of the issues, 

or misleading the jury, or by considerations of undue delay, or needless presentation of cumulative 

evidence.” Blasdell v. State, 384 S.W.3d 824, 831 n.18 (Tex. Crim. App. 2012) (citing TEX. R.

EVID. 403); see also Kelly, 824 S.W.2d at 572 n.11 (“Rule 702 incorporates Rule 402 and 403 

analyses.”). As the Court of Criminal Appeals has stated: “A judicious application of the Rule 702 

helpfulness standard and Rule 403 balancing factors is necessary...on a case-by-case basis...[and]

will depend upon factors such as the content of the testimony, the context in which it is offered, 

and the state of the evidence.” Id. at 831 (citing Ortiz v. State, 834 S.W.2d 343, 347 (Tex. Crim.

App. 1992), superseded by statute on other grounds as stated in Ellison v. State, 201 S.W.3d 714, 

717 (Tex. Crim. App. 2006)).

Once this inquiry is satisfied, an expert can expect that his testimony will be subject to 

rigorous cross-examination. See, e.g., In re Melton, 597 A.2d 892, 903 (D.C. 1991) (citing In re 

Japanese Elec. Prods. Antitrust Litig., 723 F.2d 238, 277 (3d Cir. 1983), rev’d on other grounds, 

475 U.S. 574 (1986). But objections to its reliability, such as complaints of analytical gaps, will 

most likely go to the weight of the evidence rather than to its admissibility. Id. at 904 (citing 

Bertolotti v. Dugger, 883 F.2d 1503, 1517 (11th Cir. 1989), cert. denied, 497 U.S. 1032 (1990)); 

Taylor v. State, 555 S.W.3d 765, 780 (Tex. App.—Amarillo 2018, pet. ref’d). “Juries are 

intelligent enough, in light of the availability of such cross-examination, to ignore what is 
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unreliable or unhelpful.” In re Melton, 597 A.2d at 903 (citing In re Japanese Elec. Prods. 

Antitrust Litig., 723 F.2d at 279). 

We note that an accident reconstructionist’s lack of knowledge regarding the 

innerworkings of the data system or software he uses to complete his work does not constitute an 

analytical gap. Brantley v. State, 606 S.W.3d 328, 341 (Tex. App.—Houston [1st Dist.] 2020, no 

pet.) (citing TXI Transp. Co. v. Hughes, 306 S.W.3d 230, 240 (Tex. 2010) (rejecting the argument

that a reconstructionist’s “lack of knowledge of the manufacturing process of the black box and its 

accelerometer or of the black box’s error rate affected the reliability of his testimony” because his 

testimony “tied the black box data into evidence obtained at the scene, which supported his 

conclusions”).

2. Admissibility of Expert Testimony Under the Sixth Amendment

Under the Sixth Amendment, a defendant has a constitutional right to confront the 

witnesses against him. Boutang, 402 S.W.3d at 786. (citing U.S. CONST. amend. VI). This 

protection includes the right to cross-examine testing analysts who produce reports that the State 

wishes to admit at trial. See Burch v. State, 401 S.W.3d 634, 638 (Tex. Crim. App. 2013) (citing 

Bullcoming v. New Mexico, 564 U.S. 647 (2011)). It does not, however, disqualify an expert from 

testifying if he is unable to answer all the defendant’s questions on cross-examination. See Webb 

v. Tex., 409 U.S. 95, 98 (1972) (citing Washington v. Texas, 388 U.S. 14, 19 (1967)) (“Just as an 

accused has the right to confront the prosecution’s witnesses for the purpose of challenging their 

testimony, he has the right to present his own witnesses to establish a defense.”). An expert’s 

capacity to answer questions related to his area of testimony is measured and evaluated under Rule

702 as a “fit” test regarding an expert’s helpfulness to the jury. Tillman v. State, 354 S.W.3d 425, 

438 (Tex. Crim. App. 2011); Jordan v. State, 928 S.W.2d 550, 555 (Tex. Crim. App. 1996).
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D. Analysis

1. Trial Testimony

When Sergeant Windsor testified at trial, the trial court initiated the voir dire examination:

Sergeant, you’re here because I believe the State intends to proffer 

you as an expert witness, maybe in accident reconstruction or 

something to that effect, I believe. So, the defense has the right and 

frankly an obligation to make sure that you have the credentials to

testify that way. And so, the parties are going to proceed to try to 

establish those credentials, okay? Y’all may proceed.

Regarding his credentials, Sergeant Windsor testified that he was assigned to the traffic 

investigations detail in September 2017. In that role, he received intermediate and advanced crash 

investigation training. Both training courses lasted one week and were given by Texas A&M. He 

also trained to be an analyst for the air bag control modules at the Bexar County Sheriff’s 

Academy, and he learned to be a trainer for downloading or imaging air bag control modules. As 

an analyst and trainer, Sergeant Windsor testified several times as an expert at trial.

Regarding the relevance of his expertise, Sergeant Windsor testified that data retrieved 

from airbag control modules was regularly used in traffic investigations, especially in “criminal 

death cases and ones involving serious bodily injury.” He testified that he has imaged ACMs to 

retrieve collision data over a hundred times and that the data was consistently corroborated by 

physical evidence from crash sites.

In Trejo’s case, Sergeant Windsor requested and was granted a search warrant to retrieve 

collision data from Trejo’s car. He stated that he imaged the car’s ACM successfully and that it 

was corroborated by physical evidence from the crash site. For example, there was no roadway 

evidence of braking, and the car’s collision data confirmed that Trejo was not engaging his brakes

at the point of impact. Also, the data suggested the car was involved in a frontal collision, which 

was corroborated by the physical crash evidence. 
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Sergeant Windsor testified that Trejo’s ACM recorded his car’s speed during the five 

seconds leading up to the crash. With a minor adjustment for Trejo’s tire size, evidence showed 

that Trejo was driving approximately eighty miles per hour at five seconds prior to impact. The 

data, as well as some available surveillance footage from a nearby HEB, showed that Trejo pressed 

his brake pedal twice in the five seconds before the crash. Then the crash data showed that Trejo 

accelerated into the collision. In the tenth of a second prior to impact, Trejo was driving 

approximately seventy miles per hour. Sergeant Windsor confirmed that the collision damage 

corroborated the car’s speed data for the crash. He also confirmed that a deputy witness estimated 

Trejo’s speed prior to the crash to be around eighty-four or eighty-five miles per hour.

When asked about the version of software used to create the car’s data report, which was 

not current at the time of trial, Sergeant Windsor explained that software company Bosch regularly

issues updates, but that those updates may not result in changes to data reports. Here, Sergeant 

Windsor used version 17.7 to create the original crash investigation report. Prior to trial, he 

compared the report to a reading from version 17.9; he testified that there were no changes to the 

report after two software updates. Trejo pointed out that since the report was created, Bosch issued 

twelve more software updates, but did not elaborate on the updates or provide a report with 

different results.

Trejo questioned whether Sergeant Windsor could speak to the internal workings of the 

Bosch data translator and identify what, if any, event data may be missing from the report 

generated by the Bosch software, since the report contained a disclaimer that some data retrieved

by the program may not be translated by the program. Sergeant Windsor answered that he could 

not explain how the software translated data retrieved from a car’s ACM or identify what data 

might be excluded in the translation. He could only testify that the Bosch software reported a 

complete and successful data translation in Trejo’s case.
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Trejo questioned Sergeant Windsor as to how Bosch’s software calculated the speed of a 

car in the five seconds prior to collision. Sergeant Windsor answered that the speed data was 

derived from the car’s drive wheels but could not describe the computer process nor replicate it 

personally. When Trejo suggested that Sergeant Windsor would be unable to check for errors or 

troubleshoot issues that might arise in the software’s speed analysis, Sergeant Windsor answered 

that the software detects and reports its own errors and that none were detected or reported in 

Trejo’s case. 

Lastly, Trejo challenged Sergeant Windsor’s speed conclusions based on the car’s tire size

because Sergeant Windsor did not and could not calculate the conclusion independently. Sergeant 

Windsor stated that he used a commercially available web-based calculator to adjust the report’s 

speed estimate because Trejo’s tires were slightly wider than default. The difference increased 

Trejo’s estimated speed by about two miles per hour. Sergeant Windsor testified that the use of 

the web-based calculator to make the speed adjustment based on the size of a car’s tires was a 

generally accepted practice among accident reconstructionists.

After the voir dire examination, Trejo objected to Sergeant Windsor’s ability to answer 

questions about the Bosch software:

We’ll let you make your own decision as per the expert. But our

objection is going to be [Trejo] is going to get denied his Sixth 

Amendment right to confrontation because to question and

challenge this evidence and test this evidence before this jury, this 

witness cannot answer basic questions about it.

The trial court overruled the objection and allowed Sergeant Windsor to provide expert testimony.

2. Admissibility Under Rule 702

Trejo now reiterates his argument that the State deprived him of the ability to effectively 

test the State’s evidence before the jury because Sergeant Windsor could not answer his questions 
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about the innerworkings of Trejo’s ACM or the Bosch software used to read it, but he effectively 

overstates the State’s burden under Rule 702.

4 See Rhomer, 569 S.W.3d at 670. 

Sergeant Windsor was qualified to testify regarding traffic investigations and ACM 

imaging by virtue of his training and experience. See id. at 671. He was the right fit because his 

background in accident reconstruction and ACM imaging made it possible for him to provide

conclusions about Trejo’s driving at the time of his collision, which would have helped the jury 

decide whether Trejo was reckless. See id. at 669; TEX. PENALCODE ANN. § 19.04 (manslaughter). 

Sergeant Windsor’s testimony was reliable because it was based on evidence that he observed at 

the scene compared against the report produced from Trejo’s car’s ACM. See id. at 672 n.1. 

Like in Rhomer, we agree that “(1) the field of accident reconstruction is a legitimate one, 

(2) the subject matter of [the expert’s] testimony was within the scope of that field, and (3) his 

testimony properly relied upon and utilized the principles involved in the field, i.e., examining the 

physical evidence in the context of the crash site to draw conclusions about the location and cause 

of the crash.” Id. at 672. 

To the extent that Trejo’s cross-examination revealed the limits of Sergeant Windsor’s 

knowledge of the Bosch software he used to perform his investigation, we disagree that Trejo has 

established a basis for witness exclusion, as the answers to these questions lie outside the scope of 

proffered expertise. See Brantley v. State, 606 S.W.3d at 341. The trial court did not abuse its 

discretion in admitting his testimony. See id.; Rhomer, 569 S.W.3d at 672.

4 Trejo did not object under Rule 702, but to the extent that his objection can be understood to challenge Sergeant 

Windsor’s qualification or the reliability of his testimony, we conduct a Rule 702 review. Bekendam v. State, 441 

S.W.3d 295, 301 (Tex. Crim. App. 2014).
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3. Admissibility Under the Sixth Amendment 

When Trejo argued at trial that Sergeant Windsor’s knowledge base was too narrow to 

afford Trejo a meaningful cross-examination, he conflated his Sixth Amendment right to present 

a full defense with his right to thoroughly cross-examine the State’s witnesses. See Webb v. Tex., 

409 U.S. at 98. He now suggests that Sergeant Windsor’s limitations should have resulted in his

exclusion as a witness under the Sixth Amendment, because the “State still needs to have a witness 

who is competent to testify to the truth of the statements in the report.” In support of his argument,

Trejo cites an Intoxilyzer case: Boutang v. State, 402 S.W.3d 782, 788 (Tex. App.—San Antonio 

2013, pet. ref’d). We must note here that the admissibility of Intoxilyzer testimony depends on 

specific and technical requirements. See id. (citing Harrell v. State, 725 S.W.2d 208, 209‒10 (Tex.

Crim. App. 1986)). In Boutang, having a witness who was competent “to testify as to the truth of 

the report’s statements” meant that it was sufficient for the testifying analyst to be a certified 

Intoxilyzer operator who “was familiar with the machine’s maintenance, calibration, and 

functioning.” Id. We concluded that the person who mixed a reference-solution for blood-alcohol 

testing was not required to lay foundation at trial based, in part, on the holding in Bullcoming that 

the Sixth Amendment is satisfied when the State calls the author of a report to be available for 

cross-examination as to its conclusions. Id. (citing Bullcoming v. New Mexico, 564 U.S. 647 

(2011)). That is exactly what happened in this case—the State called the analyst who generated 

the collision data report to testify to the truth of its contents and to be available for crossexamination, thereby satisfying the requirements of the Sixth Amendment right to confront adverse 

witnesses. See id. 

The State offers Nguyen v. State, No. 05-20-00241-CR, 2022 WL 3714494, at *6 (Tex. 

App.—Dallas Aug. 29, 2022, pet. ref’d) (mem. op., not designated for publication), as a case where 

the Fifth Court of Appeals considered an appellant’s complaint that the accident reconstructionist’s 
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report, which was produced using collision data software, violated his Sixth Amendment right to 

confront adverse witnesses. While the reasoning in Nguyen is well-taken, the difference between 

the two cases is that Nguyen complained that the expert’s report was hearsay, while Trejo 

complains that Sergeant Windsor was not knowledgeable enough to justify the conclusions in his 

report. But to the degree that we can read Trejo’s argument to mean that the innerworkings of 

Trejo’s ACM and the Bosch software used to read it could be considered testimonial, we align 

with Nguyen and reject Trejo’s argument. See Nguyen, 2022 WL 3714494, at *8 (citing State v. 

Ziegler, 855 N.W.2d 551, 557 (Minn. Ct. App. 2014)). We overrule Trejo’s second and third 

issues.

CONCLUSION

Based on the above, we conclude that Trejo waived his extraneous offense argument 

against the admission of his driving record at his punishment-phase trial. We also conclude that 

the trial court did not abuse its discretion under Texas Rule of Evidence 702 by admitting Sergeant 

Windsor’s expert testimony regarding his crash investigation. Lastly, we disagree that the 

admission of Sergeant Windsor’s testimony violated his Sixth Amendment right to confront 

adverse witnesses. The trial court’s judgment is affirmed. 

Patricia O. Alvarez, Justice

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