October 22, 2018- State of New Mexico v. Emily A. Ruffin, No. A-1-CA-35424

I 	IN THE COURT OF APPEALS OF THE STATE OF NEW MEXICO
2 Opinion Number: ______
3 Filing Date: OCTOBER 22, 2018
4 	NO. A-1-CA-35424
5 	STATE OF NEW MEXICO,
6 	Plaintiff-Appellant,
7 V.
8 EMILY A. RUFFIN,
9 	Defendant-Appellee.
10 	APPEAL FROM THE DISTRICT COURT OF BERNALILLO COUNTY
11 	Jacqueline D. Flores, District Judge
12 Hector H. Balderas, Attorney General
13 	Santa Fe, NM 	.
14 Laurie Blevins, Assistant Attorney General
15 	Albuquerque, NM
16 	for Appellant
17 Dan Cron Law Firm, P.C.
18 	Kitren Fischer
19 Dan Cron
20 Santa Fe, NM·
21 	for Appellee
Court of Appeals of New Mexico
Filed 10/22/2018 10:14 AM
Mark Reynolds

1 	OPINION
2 HANIS EE, Judge.
3 {I} 	The State appeals the district court's pretrial ruling prohibiting one of its
4 witnesses from testifying as an expert. We affirm in part, reverse in part, and remand
5 for further proceedings.
6 I. 	BACKGROUND
7 	{2} 	At approximately 7:30 p.m. on October 18, 2013, Deputy Leonard Armijo
8 responded to a report of a two-vehicle accident involving a Ford Bronco and Toyota
9 4Runner. Upon arriving at the scene, Deputy Armijo observed a Ford Bronco lying
10 	on its side with a deceased individual inside. Defendant Emily A. Ruffin was
11 	standing in front of the Ford Bronco and told Deputy Armijo she wa~ the driver of
12 the Toyota 4Runner. She was in a hurry to pick up a friend from the airport when
13 	her phone rang and fell to the floor. When she looked at the floor, the Ford Bronco
14 "swerved and cut in front of her, which had caused the crash." Deputy Armijo
15 	detected an odor of alcohol while talking with Defendant, prompting him to call a
16 DWI unit to his location. Deputy Johan Jarefio responded and after investigating
17 Defendant for DWI, placed her under arrest. Defendant was charged, inter alia, with
18 	homicide by vehicle and driving while under the influence of intoxicating liquor or
19 	drugs.

I 	{3} 	A week before trial was scheduled, the State, for the first time, notified the
2 district court and defense counsel that it intended to qualify Deputy Armijo as an
3 expert witness in, as the State later clarified, "crash investigations." The district court·
4 neither ruled _on the admissibility of Deputy Armijo's proposed expert testimony,
5 nor accepted Deputy Armijo as 	an expert witness under Rule 	11-702 NMRA
6 (providing the requirements for a witness to be qualified and give an opinion as an
7 expert).
8 	{4} 	Four days before trial was scheduled, Defendant filed a motion in limine,
9 seeking to prohibit Deputy Armijo from testifying as an expert witness on the issue
IO 	of causation and in regard to accident reconstruction, and to limit his testimony to
11 	only his personal observations during his investigati6n of the accident scene. During
12 the hearing on Defendant's motion, held the day before trial was 	scheduled,
13 	Defendant also argued that Deputy Armijo's proposed expert testimony should also
14 be excluded under Rule 	11-403 NMRA because it bore "a legitimate risk 	of
15 	misleading the jury."
16 	{5} 	During the hearing, Deputy Armijo testified that for approximately eight years
17 he had been assigned to the DWI Traffic Unit of the Bernalillo County Sheriffs
18 .Department. In conjunction with his assignment, he attended a 240-hour, three-phase
19 training course in crash investigations and reconstruction. As part of the first phase
20 	of training-"at-scene 	crash 	investigations"-Deputy 	Armijo 	learned 	how 	to
2

1 respond to crash investigations, assist at and protect the scene, and observe points of
2 impact, "skid marks," "yaw marks," "other debris deposited on the asphalt," and
3 vehicles at their "final rest." During the second phase of training-"advanced at-
4 	scene 	crash"-he 	learned 	"airborne 	equations, 	what 	vehicles 	would 	become
5 airborne[,] ... speed analysis, crash analysis, [and] what causes vehicles to ·change
6 directions." Deputy Armijo testified that to conduct a speed analysis, "[yJou have to-
7 ascertain what's called the coefficient of friction or what is commonly referred to as
8 the drag factor of the roadway[,]" which is determined by using a mathematical
9 equation. During the third and final phase of training-"crash reconstruction"-
10 Deputy Armijo learned how to reconstruct a crash, which involves observing the
11 	scene, looking at the crash damage, looking at the position of the vehicles, and
12 looking for "any road evidence to include skid marks, [and] vehicle debris[.]" He
13 	testified this "teaches you where to locate the area of impact, where the crash
14 occurred, how it occurred, and how the vehicles sustained the damage that they've
15 	sustained."
16 	{6} 	Deputy 	Armijo 	explained 	that 	while 	a 	sergeant 	can 	override 	his
17 recommendation as to whether a full accident reconstruction should be conducted,
18 	he only conducts such a reconstruction when there are no independent witnesses, he
19 has no corroborating statements from the drivers, and/or the evidence does not match
20 with what he observes at the scene of the accident. Deputy Armijo testified that,
3

1 without conducting a full reconstruction of a given accident, he is only able to form
2 	an opinion regarding:
3
4
5
6
.7
8
[H]ow the vehicles came together. What contacted. What is on each of
the vehicles. There's specific damage to each of the vehicles that the
vehicles will sustain during the contact of the vehicles. It's basically
like a jigsaw puzzle. You can put those two vehicles together. As long
as the damage matches up to what the evidence shows, reconstruction
wouldn't be necessary.
9 D~puty Armijo testified that he had investigated over five thousand crashes-three
10 hundred 	eighty-seven 	of which 	involved 	great 	bodily 	injury 	or 	fatality-· and
11 	performed full accident reconstructions in only eleven cases. During ensuing court
12 proceedings, he had been qualified as an expert in "crash investigations" on four
13 	prior occasions, and in "crash reconstruction" on six occasions.
i4 	{7} 	In 	this 	case, 	Deputy 	Armijo 	decided 	not 	to 	conduct 	a 	full 	accident
15 	reconstruction "because what I was looking at, it was quite obvious, it was quite a
16 	simple crash." Deputy Armijo observed "specific damage" to the Ford Bronco's red
17 tail light lens, as well as to the clear head light lens of Defendant's vehicle. He then
18 	"walked" the scene of the accident and located pieces of the vehicles' red and clear
19 	lenses deposited on the road approximately seven or eight hundred feet from the
20 vehicles' resting points, which helped him locate the apparent point of impact.
21 	Although he did not see any "braking marks on either vehicle[,]" Deputy Armijo
22 	observed yaw marks, which he stated are consistent with a vehicle sliding sideways,
4

1 and gouge marks, which he explained indicate a vehicle's roof and/or metal making
2 contact with the road.
3 	{8} 	· While discussing the Ford Bronco, Deputy Armijo stated it was "fairly
4 obvious" that it had rolled over. When asked what starts a rollover, Deputy Armijo
5 stated:
6
7
8
9
10
11
The stability of that vehicle has been compromised by another vehicle
coming into contact with it. Once that vehicle has gone into the yaw
marks sliding sideways, it's inevitable that vehicle is going to roll over
due to the fact that the make and model of that vehicle, the speeds, and
once the rims come in contact with the pavement[,] ... [i]t's going to
roll. 	·
12 In addition to not undertaking a full accident reconstruction, Deputy Armijo did not
13 	use 	any 	mathematical 	formulae 	in 	conjunction 	with 	his 	observations 	and
14 	determinations regarding the accident scene, including those that would be necessary
15 	to ascertain vehicle speed.
16 	{9} 	On 	cross 	examination, 	defense 	counsel 	asked 	Deputy 	Armijo 	about
17 Defendant's Exhibit A, Deputy Armijo's handwritten field notes concerning the
18 	accident. Deputy Armijo admitted that he did not write speed calculations, rollover
19 sequence calculations, or any other type of calculations in his field notes. He also
20 	admitted that he "did not perform a timeline analysis of what occurred at various
21 	points in the crash," take crash measurements, analyze scratch patterns on the Ford
22 Bronco to determine how many times it rolled, measure the "distance in the roll
23 	sequence," nor return to the scene of the accident during "daylight hours[.]" Deputy
5

1 Armijo conceded he did not analyze data from the crash data recorder, and did not
2 collect or take any_ daytime photographs of the "roadway fragments." Finally,
3 defense counsel presented Deputy- Armijo with Exhibit B, the diagram of the
4 accident created by another officer on the scene, Deputy Phil Gonzales. Deputy
5 Armijo was unable to say whether Deputy Gonzales documented the "beginning and
6 end of the roll sequence" or the location of the yaw marks.
7 	{to} 	Following testimony, 	the 	State 	explained 	it planned to 	present Deputy ·
8 Armijo's expert opinion as to the cause of the crash and that, based on the yaw and
9 gouge marks on the road and damage to the Ford ~ronco, the Ford Bronco had rolled
10 	over. 	The 	district court first 	expressed its general 	skepticism with qualifying
11 	investigatory law enforcement officers as expert witnesses because they "sort of
12 have a stake in the outcome." It then expressed its more specific concern that Deputy
13 	Armijo was unable to articulate a methodology "to·render an opinion that would be
14 reliable to the jury[,]" and that his opinion would therefore be "more confusing to
15 	the jury than helpful." Although the State argued that Deputy Armijo's testimony
16 would not be based on scientific evidence, 	but rather his training, 	skill, 	and
17 knowledge, the district court ruled that Deputy Armijo would not be qualified as an
18 	expert witness under Rule 11-702. While the district court recognized that Deputy
19 Armijo "had extra training" and that the issue of causation was "key in this case," it
20 nonetheless ruled that it was prohibiting Deputy Armijo from testifying as to "any
6

1 conclusions" he reached regarding the cause of the accident. The district court ruled
2 that Deputy Armijo could only testify about his personal observations.
3 	{11} 	The State appealed the district court's ruling to this Court under NMSA 1978,
4 Section 39-3-3(8)(2) (1972), before a jury was impaneled, certifying "that this
5 appeal is not taken for the purpose of delay, and the evidence is a substantial proof
6 of a fact material to the proceeding." On appeal, the State elaborates that, if qualified
7 as 	an expert, 	Deputy Armijo would 	have 	testified based on his training 	and
8 experience, opined "that Defendant's rear-ending [of] the vehicle traveling in front
9 of her caused the collision[,]" educated the jury about yaw and gouge marks, and
10 testified that he could "match the damage up" from the two vehicles based on the
11 	specific damage sustained by both vehicles. Furthermore, Deputy Armijo would
12 testify that, in rear-ending the Ford Bronco, Defendant's vehicle "caus[ed] it to
13 	swerve sideways, then roll an unknown number of times, a theory buttressed by the
14 physical damage to the [Ford] Bronco's roof support pillars and roof."
· 15 	II. 	DISCUSSION
16 	{12} 	Appealing the district court's ruling, the State argues that (1) its appeal is
17 permitted under Section 39-3-3(8)(2); (2) the district court erred in prohibiting
18 	Deputy Armijo from testifying as to any of the.conclusions he reached as a result of
19 his investigation, including those that could be deemed "lay opinions"; (3) the
20 district court erred in prohibiting Deputy Armijo from testifying as an expert under
7

1 Rule 11-702; and (4) the district court erred in excluding Deputy Armijo's expert
2 testimony under Rule 11-403. We address each argument in tum.
3 	A. 	The State's Appeal Under Section 39-3-3(B)(2) Is Proper
4 	{13} 	Before considering the merits of the State's appeal~ we must first resolve
5 whether the State had a right, prior to trial, to appeal the district court's ruling
6 precluding Deputy Armijo from testifying as an expert witness under Rules 11-702
7 and 11-403. Under Section 39-3-3(B)(2), the state may appeal a district court's order
8 excluding evidence if it "certifies to the district court that the appeal is not taken for
9 purpose of delay and that the evidence is a substantial proof of a fact material in the
10 	proceeding." Defendant does not challenge the State's appeal on the basis 	of
11 	timeliness, see State v. Mendez, 2009-NMCA-060, 111, 146 N.M. 409, 211 P.3d
12 	206 (concluding that an appeal under Section 39-3-3(B)(2) is timely when initiated
13 	before the jury is sworn), rev'd on other grounds by 2010-NMSC-044, 148 N.M.
14 	761, 242 P.3d 328; rather, Defendant argues that the State's appeal is not proper
15 	because the district court's "ruling did not make it impossible for the State to prove
16 an element of its case" under Section 39-3-3(B)(2).
17 	{14} 	Substantively, the 	State's appeal must concern a court's 	suppression 	or
18 	exclusion of evidence that "could constitute substantial proof of a material fact[.]"
19 Mendez, 2010-NMSC-044, 114. Defendant relies on this Court's holding in State v.
20 Romero, 2000-NMCA-029, 128 N.M. 806, 999 P.2d 1038, which he.Id that the
8

1 State's appeal was proper under Section 39-3-3(B)(2) because the district court's
2 ruling "controlled the course of the presentation of material evidence in the case,
3 given the [s]tate's theory." Romero, 2000-NMCA-029, 18. We explained that "[t]he
4 excluded evidence went to the very heart of the proof required to establish an
5 essential element of the [s]tate's case ... [and t]he court's ruling made it impossible
6 for the [s]tate to prove an element of its case." Id. 19. However, we later clarified
7 the· substantive standard: "[W]e do not read Romero as allowing the state to appeal
8 only when the district court's ruling makes it impossible for the state to prove its
9 case. Rather, we interpret Romero 	as requiring that the excluded evidence be
10 important or significant, as opposed to evidence of minor consequence." Mendez,
11 	2009-NMCA-060, 112 (emphasis added). We discuss whether the State's appeal is
12 proper under the substantive standard as clarified by this Court in Mendez.
·13 	{I 5} 	When causation is contested in a vehicular homicide case, the state must prove
14 	beyond a reasonable doubt that the defendant's unlawful actions caused the death
15 	"in a natural and continuous chain of events[.]" State v. Simpson, 1993-NMSC-073,
16 113, 116 N.M. 768, 867 P.2d 1150 (internal quotation marks and citation omitted);
17 see UJI 14-251 NMRA (explaining that when causation is in issue, the state must
18 	prove beyond a reasonable doubt that the defendant's act, "in a natural and
19 continuous chain of events, uninterrupted by an outside event, resulted in the death
.20 and without which the death would not have occurred"). To prove causation, the
9

1 State may, but is not required to, call an expert witness. See State v. Plater.a, 2017-
2 NMCA-083, ,-r 18,406 P.3d 557 (concluding that an expert was not required to prove
3 cause of death in a vehicular homicide case); cf State v. Jimenez, 2017-NMCA-039,
4 ,-r 79, 392 P.3d 668 (noting that the state's decision "to call or not call a witness is a
5 matter of trial tactics and strategy within the control of counsel" (internal quotation ·
6 marks and citation omitted)). Defendant directly contests the State's theory that she
7 caused the accident because she was intoxicated, asserting instead that the accident
8 resulted from her momentary inattention when the Ford Bronco moved into her lane.
9 Although Deputy Armijo could offer no opinion regarding whether or not Defendant
10 was intoxicated, the State nonetheless sought to qualify him as an expert who would
11 	testify as to the cause of the accident from the standpoint of the sequence of events
12 	in which it occurred-a point of apparent dispute which bears upon the element of
13 	causation, which the district court identified as "key in.this case." Even Defendant
14 acknowledges that the 	district 	court's ruling prohibited Deputy Armijo 	from
15 	testifying that Defendant caused the accident itself. Under these circumstances, and
16 without the benefit of a developed record regarding the precise nature of the dispute
17 regarding the collision and its aftermath, we have no basis to conclude that the
18 	circumstances 	of an 	accident 	are 	not 	"important 	or 	significant" 	to 	a jury's
19 	determination regarding the element of causation. See Mendez, 2009-NMCA-060,
20 ,-r 12. As such, the district court's ruling adversely impacted the State's capacity to
10

1 present evidence that went to the "heart of the proof required to establish the
2 element" of causation. Id. (internal quotation marks and citation omitted); cf State
3 	v. Gonzales, 2012-NMCA-034,, 5,274 P.3d 151 (noting that an expert opinion is
4 evidence). We conclude in this circumstance that, under Section 39-3-3(B)(2), the
5 State may, pretrial, appeal from the deprivation of its capacity to prove the element
6 	of causation by means of an expert witness. We therefore proceed to the merits of
7 the State's appeal.
· 8 B. 	Deputy Armijo's "Lay Conclusions"
9 	{16} 	The State first argues that by prohibiting Deputy Armijo from testifying as to
10 "any conclusions" he reached regarding the circumstances of the accident, the
11 	district court impermissibly prohibited him from offering certain conclusions that
12 	even a layperson would be permitted to offer at trial. As an example, the State cites
13 	State v. Wildgrube, 2003-NMCA-108, 134 N.M. 262, 75 P.3d 862, where this Court
14 held that a law enforcement officer who had observed the scene of the accident was
15 	permitted to testify as a lay witness under Rule 11-701 NMRA about the location of
16 the debris and to offer an opinion about the point of impact through a diagram.
17 	Wildgrube, 	2003-NMCA-108, 	, 	15. 	Wildgrube 	involved 	the 	officer 	inputting
18 	measurements he had taken at the scene of the accident into a computer program
19 which then produced a diagram of the scene. Id. , .12. The officer then testified,
20 without objection, as to the evidence he collected, the methods he used to gather the
11

1 evidence, the methods he used to measure the location of debris found at the scene,
2 the methods he used to create the computer-generated diagram, and his opinions
3 about the diagram's accuracy and "the meaning ofthe debris path." Id.,, 12-13.
4 	{17} 	In this case, however, the State planned to offer Deputy Armijo's testimony.
5 to not only his personal observations, but also to explain his conclusions regarding
6 what those observations mean and opine as to the cause of the accident in light of
7 his 	specialized training and experience. And, unlike in 	Wildgrube, 	Defendant
8 objected to the proposed testimony. The State argued to the district court that Deputy
9 Armijo's opinion in this case and general understanding of traffic investigations,
10 yaw marks, speed calculations, and crash data analysis were a product of his
11 	specialized training and experience not possessed by a regular police officer. Despite
12 	its similarity to the accident scene evaluation undertaken in Wildgrube, we conclude
13 	that the testimony excluded by the district court was, in this circumstance, expert
14 testimony. See State v. Winters, 2015-NMCA-050,, 11, 349 P.3d 524 (noting that
15 	"opinion testimony oflay witnesses is generally confined to matters which are within
16 the common knowledge and experience of an average person" (internal quotation
17 marks and citation omitted)); cf State v. Vargas, 2016-NMCA-038, ,, 22-23, 368
18 	P.3d 1232 (concluding that an officer's testimony about the technical properties of
19 	stun guns and identifying stun gun injuries was based on his law enforcement
20 training and experience, and was therefore expert testimony). We accordingly hold
12

1 that the delineation of lay versus expert testimony in this instance is not controlled
2 by Wildgrube and we have no basis on the limited record before us to reverse the
3 district court's conclusion that Deputy Armijo's proposed testimony was not lay
4 opinion testimony.
5 	C. 	Deputy Armijo's Expert_Test~mony
6 	{18} 	Having concluded that the district court excluded conclusions reached by
7 Deputy Armijo that constitute expert testimony, we next address whether it erred in
8 doing so. Our analysis begins with Rule 11-702, which provides that "[a] witness
9 who is qualified as an expert by knowledge, skill, experience, training, or education
10 may testify in the form of an opinion or otherwise if the expert's scientific, technical,
11 	or other specializ,ed knowledge will help th~ trier of fact to understand the evidence
12 or to determine a fact in issue." A witness may be admitted as an expert under Rule
13 	11-702 upon the satisfaction of three requirements: (1) "that the expert be qualified";
14 	(2) that the testimony "will assist the trier of fact"; and (3) that the expert's testimony
15 	concern "scientific, technical or other specialized knowledge." State v. Alberico,
16 1993-NMSC-047, 1143-45, 116 N.M. 156, 861 P.2d 192 (internal quotation marks
17 omitted). "[T]he admission of expert testimony ... is peculiarly within the sound
18 	discretion of the [district] court and will not be reversed absent a showing of abuse
19 	of that discretion." Id. 	158. Although Defendant argues that the district court's
· 20 exclusion of Deputy Armijo's expert testimony was proper because Deputy Armijo
13

1 was not sufficiently qualified, the district court did not exclude his expert testimony
2 on that ground. Rather, the district court ruled that the proposed expert testimony
3 lacked a reliable methodology, a ruling that implicates the scientific knowledge
4 element of the third requirement for the admission of expert testimony. See Andrews
5 v. 	US. 	Steel Corp., 2011-NMCA-032, ,r,r 12-13, 	149 N.M. 461, 250 P.3d 887
6 (holding that, under Alberico, and Daubert v. Merrell Dow Pharmaceuticals, Inc.,
7 509 U.S. 579 (1993), "the proponent of [scientific expert] testimony must establish
8 the reliability of the science and methodology on which it is based" to satisfy the
9 third requirement for expert testimony). We therefore limit our discussion of the
10 	district court's ruling to its stated basis for exclusion under Rule 11-702. See Rule·
11 	12-3 21 (A) NMRA ("To preserve an issue for review, it must appear that a ruling or
12 	decision by the trial court was fairly invoked.").
13 	{19} 	"Where expert testimony concerns scientific knowledge, the proponent of the
14 testimony must establish the reliability of the science and methodology on which it
15 	is based." Andrews, 2011-NMCA-032, ,r 13. When determining.the admissibility of
16 expert testimony involving scientific knowledge, the district court should, pursuant
17 to Alberico and Daubert, consider. whether the testimony is "grounded in valid,
18 	objective science and [is] reliable enough to prove what it purports to prove" by
19 testing the expert's methodology. State v. Torrez, 2009-NMSC-029, ,r 21, 146 N.M~
20 331, 210 P.3d 228 (internal quotation marks and citation omitted). The Alberico-
14

l 	Daubert standard applies only to scientific expert testimony. See State v. Torres,
2 	1999-NMSC-010, ,r 43, 127 N.M. 20, 976 P.2d 20 (concluding that "the Alberico-
3 	[D]aubert 	standard 	applies 	only to 	expert testimony 	that 	relies 	on 	scientific
4 knowledge," rather than all forms of expert testimony); see also Quintana v. Acosta,
5 2014-NMCA-015, ,r 14,316 P.3d 912 (noting that the Alberico-Daubert standard
6 applies "only when the district court is evaluating the admissibility of scientific
7 .testimony"). "[T]he initial determination of whether to apply the Alberico-Daubert
8 standard entails a conclusion oflaw that is subject to de novo review." Torres, 1999-
. 9 NMSC-010, ,r 28.
10 {20} 	Thus, we first answer whether Deputy Armijo's expert testimony was based.
11 	on "scientific" knowledge, thereby requiring application of the heightened_Alberico-
12 Daubert standard, "Evidence is based on scientific knowledge if it is not self-
13 	explanatory, or if it is based on a scientific or medical principle." State v. Aleman,
14 2008-NMCA-137, ,r 6, 145 N.M. 79, 194 P.3d 110 (internal quotation marks and
15 	citation omitted); see State v. Bregar, 2017-NMCA-028, ,r,r 32-33, 390 P.3d 212
16 (noting that expert testimony involving the use of physics equations is based on
17 	scientific knowledge); cf State v. Brown, 687 P.2d 751, 754 (Or. 1984) (en bane)
18 	("The term 'scientific' . . . refers to evidence that draws its convincing force from.
19 	some principle of science, mathematics and the like."). We understand Deputy
15

1 Armijo's proposed expert testimony to fall within two distinct categories: non-
2 scientific and scientific expert testimony.
3 	1. 	Deputy Armijo's Non-Scientific Expert Testimony
4 	{21} 	To better frame the narrow scope 	of Deputy Armijo's 	scientific 	expert
5 testimony, we begin by identifying Deputy Armijo's non-scientific expert testimony.
6 As Deputy Armijo testified at the Alberico hearing, he was able to match "specific
7 damage" to the Ford Bronco's red tail light lens and the Toyota 4Runner's clear front
8 lens, which led him to conclude that the front of the Toyota 4Runner made contact
9 with the rear of the Ford Bronco. He also located the Ford Bronco's red lens and the
10 Toyota 4Runner's clear lens approximately seven or eight hundred feet from the
11 	vehicles, allowing him to conclude that the Toyota 4Runner and the Ford Bronco
12 	collided where the lenses were discovered. He planned to inform the jury about the
13 	yaw and gouge marks he observed and the phenomena those marks generally
14 	indicate. Finally, based on the yaw and gouge marks found on the road and the
15 	physical damage to the Ford Bronco, Deputy Armijo concluded and the State
16 proposed that he testify- that the Ford Bronco rolled over. Deputy Armjio's non-
17 	scientific expert testimony is 	based on his personal 	observations 	of physical
18 	evidence found at the scene, is straightforward, and appears to fit directly within the
19 	scope of his specialized training. Moreover, none of these points of testimony arose
20 from application of scientific principles or mathematic computations. We therefore
16

1 conclude that this testimony was not based on "scientific knowledge" and the district
2 court erred in applying the Alberico-Daubert standard to this testimony.
3 	{22} 	Having concluded that the district court applied the wrong legal standard, we
4 also analyze whether the district court abused its discretion in denying the admission
5 of Deputy Armijo's non-scientific expert testimony. A district court "abuses its
6 discretion when it exercises its discretion based on a misunderstanding of the law."
7 State v. Lente, 2005-NMCA-111, ,r 3, 138 N.M. 312, 119 P.3d 737. Given the district
8 court's application of the wrong legal standard to Deputy Armijo's non-scientific
9 expert testimony, we conclude it ~bused its discretion in this respect.
10 	{23} 	Our holding in this regard should not, however, be construed to command that
11 	the district court determine Deputy Armijo' s non-scientific expert testimony to be
12 	either reliable or unreliable. See Torrez, 2009-NMSC-029, ,r 21 (holding that "even
13 	with non-scientific expert testimony, the [district] court must exercise its gate-
14 keeping function and ensure that the expert's testimony is reliable"). When ruling
15 	on the admissibility of non-scientific expert testimony, the district court "must
16 	evaluate a non-scientific expert's personal knowledge and experience to determine
17 whether the expert's conclusions on a given subject may be trusted." Id. The district
18 	court tests "whether an expert's skills, experience, training, or education qualify him
19 	or her in the relevant subject ... [and] uses these same factors ... to test the validity
20 	of the expert's conclusions ... [and determine whether they] 	prove what they
17

I 	purport to prove." Id. 	,-r 22. Whereas the district court misapplied the Alberico-
2 Daubert standard to test the reliability of Deputy Armijo's methodology in the first
3 instance, on remand it should instead test the validity of Deputy Armijo's non-
4 scientific expert testimony by evaluating whether his conclusions are consistent with
5 his specialized training and experience. If answered affirmatively, Deputy Armijo's
6 non-scientific testimony would be admissible under Rule 11-702.
7 2. 	Deputy Armijo's Scientific Expert Testimony
8 	{24} 	We next discuss what we conclude to be Deputy Armijo's scientific expert
9 testimony regarding the cause of the apparent rollover. As this Court noted in
10 Bregar, expert testimony is scientific when it applies physics principles. 2017-
11 	NMCA-028, ,-r,-r 32-33. Defendant contends that Deputy Armijo planned to "testif1y]
12 to scientific matters involving math and physics." We agree. Whereas his expert
13 	opinion that a rollover occurred is based on his non-scientific knowledge, his expert
14 	opinion regarding the 	cause of the apparent rollover-in 	other words, 	why it
15 	happened vis-a-vis the colliding of the two impacted vehicles-necessarily requires
16 that he analyze the chain of events leading up to, and culminating in the Ford Bronco
17 rolling over. But by Deputy Armijo's own admission, determining how a rollover
18 	starts requires analyzing, amongst other things, the vehicles' speeds. Deputy Armijo
19 testified that analyzing speed requires the use 	of a mathematical equation to
20 "ascertain what's called the coefficient of friction or what is commonly referred to
18

1 as the drag factor of the roadway." Accordingly, pursuant to Deputy Armijo's own
2 description of the methodology needed to identify the cause of a collision that results
3 in a vehicle rollover, any expert testimony concerning the cause of this apparent
4 rollover would require application of mathematical principles and would therefore
5 be scientific expert testimony.
6 	{25} 	The State, however, argues that no scientific expertise was required for this
7 testimony. To support its argument, the State cites Duran v. Lovato in which this
8 Court held that the district court did not abuse its discretion in admitting an officer's
9 expert testimony about the "area of impact" in an accident involving a pedestrian
10 	and vehicle, and whether speed was a factor in the accident. 1982-NMCA-182,
11 	,r,r 18-19, 99 N.M. 242, 656 P.2d 905 (internal quotation marks omitted). However,
12 Duran was decided prior to both Daubert and Alberico and provides no guidance to
13 	this 	Court 	about 	distinguishing 	between 	scientific 	and 	non-scientific 	expert
14 testimony. Furthermore, to the extent that Duran remains good law after Daubert
15 	and Alberico, it is factually distinguishable from the present case. In Duran, the
16 	officer took measurements at the scene of the accident which he later used to create
17 a diagram of the accident scene and relied partly on his diagram to render his expert
18 	opinion. 1982-NMCA-182, ,r 18. Deputy Armijo did no such thing. We therefore
19 decline to extend Duran's rationale to the present case.
19

1 {26} 	The State also argues that Deputy Armijo's testimony was not subject to the
2 Alberico-Daubert standard because it was based on his specialized knowledge,
3 citing State v. Bullcoming, 2010-NMSC-007, 147 N.M. 487,226 P.3d 1 (Bullcoming
4 II), rev'd on other grounds sub nom. by Bullcoming v. New Mexico, 564 U.S. 647
5 (2011) (Bullcoming III), and State v. Bullcoming, 2008-NMCA-097, 144 N.M. 546,
6 189 P.3d 679 (Bullcoming I). In Bullcoming I, this Court first held that an officer
7 who made contact with a defendant after an accident could testify based on his
8 specialized knowledge that the defendant caused an accident because he "was under
9 the influence of some kind of intoxicating liquor." 2008-NMCA-097, ,r,r 10-11
10 	(internal 	quotation marks 	omitted); 	see Bullcoming II, 	2010-NMSC-007, 	,r 27
11 	(noting that the record indicated that the officer based his opinion on his contact with
12 the defendant). Our Supreme Court later held that the district court did not abuse its
13 	discretion in permitting the officer's testimony because he was well-qualified and
14 "[d]efense counsel did not conduct voir dire examination or otherwise challenge his
15 	qualifications." Bullcoming II, 2010-NMSC-007, ,r 29. However, both cases are
16 	factually distinguishable from this case. In Bullcoming II, the officer reached his
17 conclusion 	based 	on 	his 	observations 	that 	the 	defendant 	exhibited 	signs 	of
· 18 	intoxication and had an odor of alcohol. Id. 	,r,r 4, 27. Here, considered in sum,
19 Deputy Armijo's testimony conceded that he needed to apply physics principles to
20 discover the cause of rollovers.
20

· 1 {27} 	Lastly, the State argues that no mathematical modeling was required for
2 Deputy Armijo's expert opinion regarding the cause of the apparent rollover, citing
3 Lopez-Juarez v. Kelly, 348 S.W.3d 10 (Tex. Ct. App. 2011). In Lopez-Juarez, the
4 Texas Court of Appeals held that, "[i]n simple accidents, the accident reconstruction
5 can be conducted without mathematical modeling." Id. at 21. However, the court
6 noted that it was presented with a multiple vehicle accident, differing witness
7 accounts of the accident, and the need to use complex physics calculations to
8 determine 	fault. 	Id. 	at 	19 	n.13. 	It therefore concluded that the 	accident was
9 "complex" which required mathematical modeling. Id. 	at 22. Although the case
10 	before this Court lacked the multivehicle complexity identified by Lopez-Juarez as
11 	a basis for requiring a scientific level of expertise, the collision lends itself to two
12 	differing interpretations: (1) Defendant's contention that the accident was caused by
13 	a combination of her inattention and the Ford Bronco traveling from its own lane
14 	into hers; and (2) Deputy Armijo's proposed conclusion that based on the tail and
15 	head light lenses deposited on the road, the yaw and gouge marks discovered on the
16 	road, and the damage to the Ford Bronco, Defendant rear-ended the Ford Bronco,
17 causing the rollover and the driver's death. As stated above, the methodology
18 	described by Deputy Armijo indicated his need to apply physics principles and
19 	mathematical calculations to determine whether his suspected conclusion regarding
20 the rollover was supported by scientific methodology. In other words, Deputy
21

1 Armijo's specialized knowledge is no substitute for scientific methodology when
2 expert testimony is of a scientific nature or depends upon the application of scientific
3 principles. 	Cf 	Aleman, 	2008-NMCA-137, 	, 6 	(requiring 	application 	of 	the
4 heightened Alberico-Daubert standard to evidence based on scientific knowledge,
5 i.e., knowledge that is not self-explanatory or is based on scientific or medical
6 principles) .
.7 	{28} 	For the aforementioned reasons, we conclude that application of Duran,
8 Bullcoming, and Lopez-Juarez is inapposite here, and that Deputy Armijo's expert
9 testimony regarding the cause of the apparent rollover in this case is based on
10 	scientific knowledge and must be subjected to the heightened _Alberico-Daubert
11 	standard. See Daubert, 509 U.S. at 590 (holding that "in order to qualify as 'scientific
12 knowledge,' an inference or assertion must be derived by the scientific method").
13 	But here, 	Deputy Armijo 	elected not to 	conduct a full 	reconstruction, 	apply
14 mathematical formulae, 	or engage in other procedures consistent with a final
15 	determination of what happened and why. Deputy Armijo neither testified to, nor
16 	documented, any discernible methodology from which the district court could test
· 17 the reliability of his opinion. Reiterating that our Supreme Court has given the
18 	district court broad discretion in the exclusion of expert testimony, we conclude that
19 the 	district 	court's 	exclusion 	of Deputy 	Armijo's 	proposed 	expert testimony
20 regarding the cause of the rollover was not an abuse of its discretion in light of the
22

1 facts of his investigation in this case. See State-v. Downey,' 2008-NMSC-061, ,r 30,
2 	145 	N.M. 232, 	195 	P.3d 1244 (explaining that "for scientific evidence to be
3 admissible 	under Rule 	11-702, 	the 	reasoning or methodology underlying the
4 testimony must not only be scientifically valid, it also must be properly applied to
5 the facts in [theJ issue" ( alteration, omission, internal quotation marks, and citation
6 omitted); Alberico, 1993-NMSC-047, ,r 58 (holding that the exclusion of expert
7 testimony is within the sound discretion of the district court and will not be disturbed
8 unless "manifestly erroneous" (internal quotation marks and citation omitted)).
9 D. 	Rule 11-403
10 	{29} 	Having concluded that Deputy Armijo's non-scientific expert testimony still
11 	has the potential on remand to pass muster under Rule 11- 702, we also discuss the
12 	district court's ruling that itwas nonetheless excludable under Rule 11-403. Even if
13 	expert testimony is admissible under Rule 11-702, it must be relevant under Rule
14 	11-401 NMRA and even if relevant, may be excluded under Rule 11-403. Alberico,
15 	1993-NMSC-047. ,r 55. Evidence is relevant if "it has any tendency to make a fact
16 more or less probable than it would be without the evidence" 	and it 	is 	"of
17 consequence in determining the action." Rule 11-401. Relevant evidence, although
18 	admissible under Rule 11-401, may still be excluded "if its probative value is
19 	substantially outweighed by a danger of ... unfair prejudice ... [or] misleading the
20 jury[.]" Rule 11-403. "Unfair prejudice does not mean the damage to a·defendant's
23

1 case that results from the legitimate probative force of the evidence; rather it refers
2 to evidence that tends to suggest decision on an improper basis." State v. Anderson,
3 	1994-NMSC-089, ,r 63, 118 N.M. 284, 881 P.2d 29. The district court's exclusion
4 	of evidence under Rule 11-403 is reviewed for an abuse of discretion. State v.
5 Chamberlain, 1991-NMSC-094, i19, 112 N.M. 723,819 P.2d 673.
6 	{30} 	The probative value of Deputy Armijo's testimony is high because it bears
7 directly upon whether Defendant rear-ended the Ford Bronco and caused the
8 accident, which is a key issue in this case. Although the district court did not
9 explicitly cite Rule 11-403 in its ruling, Defendant argued that the expert testimony
10 would impermissibly mislead the jury under Rule 11-403 and the district court
11 	considered whether the evidence was relevant and weighed_ its probative value
12 	against two concerns. We therefore review its exclus~on of Deputy Armijo's expert
13 	testimony under Rule 11-403. See Progressive Cas. Ins. Co. v. Vigil, 2018-NMSC-
14 	014, ,r 12, 413 P.3d 850 (concluding that an appellate court may review a district
15 	court's exclusion of evidence under Rule 11-403 when the district court fails to cite
16 the rule but the record reflects that the parties' arguments and the district court's
17 ruling were guided by the rule's principles). First, the district court noted its
18 	skepticism about permitting investigating officers to testify as experts in their own
19 	cases as they "have a stake in the outcome." Second, the district court stated that it
24

1 was concerned that Deputy Armijo's testimony would be confusing to the jury
2 because his opinion lacked a scientific basis that would render it reliable.
3 	{31} 	As to the district court's first concern, any extent to which Deputy Armijo's
4 involvement in this case had the potential to impact his testimony is a question of
5 credibility for the jury. See Alberico, 1993.;NMSC-047,, 37 (explaining that it is
6 "the most basic function of a jury to arbitrate the weight and credibility of evidence,
7 even expert opinion testimony"); Poore v. State, 1980-NMSC-035, , 5, 94 N.M.
. 	.
8 172, 608 P .2d 148 (concluding that "the credibility of the witnesses was for the jury
9 to determine"); State v. Paiz, 1999-NMCA-104,, 30, 127 N.M. 776,987 P.2d 1163
10 	(noting that "the jury acts as the sole fact[-]finder based upon its weighing of the
11 	evidence and credibility of the witnesses" (emphasis added)). Defendant, however,
12 argues that several issues arise when the State calls an investigating officer to testify
13 	as an expert witness. See United States v. Dukagjini, 326 F.3d 45, 51 (2d Cir. 2003).
14 The court in Dukagjini noted that when a case agent testifies as an expert, "the
15 	government confers upon him the aura of special reliability and trustworthiness
16 	surrounding expert testimony." Id. 	at 53 	(internal quotation marks and citation
17 	omitted). Our Supreme Court has explicitly rejected this proposition. See Alberico,
18 	1993-NMSC-04 7, , 36 (concluding that the "premise that juries are awed by the aura
19 	of the infallibility 	of expert opinion testimony and thus defer to it 1s 	flawed
20 speculation" (internal quotation marks omitted)).
25

l 	{32} 	The court in Dukagjini also noted that "there is an increased danger that the
2 expert testimony will stray from applying reliable methodology and convey to the
3 jury the 	witness's 	sweeping 	conclusions 	about 	[the 	defendants'] 	activities[.]"
4 Dukagjini, 326 F.3d at 54 (internal quotation marks and citation omitted). However,
5 the Dukagjini court explained, and we agree, that it is the responsibility of the district
6 court to remain vigilant and ensure that the expert not stray from the scope of his/her
7 expertise. See id. 	at 54-56 (noting that it is the role of district courts to remain
8 "vigilant gatekeepers" to ensure that the exp~rt witness not deviate "from the
9 strictures of Rule[ 11 7]403 and [Rule 11]702"); see also Vargas, 2016-NMCA-038,
10 ,-r,-r 13, 17 (noting that a witness may provide both lay and expert testimony in a single
11 	case, but"[ w ]hen the line between lay and expert opinion is blurred during the course
12 	of a single witness's testimony, it is the proper function of the district court, as
l 3 gatekeeper, to correct the error when raised"). Here, there was no indication that
14 Deputy Armijo was going to stray from any strictures set forth by the district court.
15 	{33} 	For these reasons, the danger of unfair prejudice or m_isleading the jury
16 	stemming from Deputy Armijo's 	involvement in this 	case is 	speculative and
17 minimal, at best, particularly given the availability of limiting jury instructions. See
18 	Statev. King, 2012-NMCA-119~ ,-r 5,291 P.3d 160 (explaining that "[a] district court
19 	abuses its discretion if its decision is obviously erroneous, arbitrary, or unwarranted,
20 or clearly against the logic and effect of the facts and circumstances of the case"
26

1 (internal quotation marks and citation omitted)); see also UJI 14-118 NMRA ("You
2 should consider each expert opinion and the reasons stated for the opinion, giving
3 them such weight as you think they deserve. You may reject an opinion entirely if
4 you conclude that it is unsound.").
5 	{34} 	As to the district court's second concern, as we have concluded above, Deputy
6 Armijo's non-scientific expert testimony did not require the district court to probe
7 whether he used a reliable methodology. The district court did not consider this
8 distinction. Rather, it found that the lack of a reliable methodology-the standard
9 applied to expert testimony based on scientific knowledge-would confuse the jury.
10 Having considered the distinction between expert testimony based on scientific
11 	versus non-scientific knowledge, we conclude that the danger of unfair prejudice or
12 misleading the jury is slight compared to the evidence's probative value. A holding
13 	to the contrary would effectively permit the district court to circumvent our Supreme
14 	Court's explicit restriction of the Alberico-Daubert standard to expert testimony
15 	based on scientific knowledge-a result we cannot permit. See Torres, 1999-NMSC-
16 	010,, 43 (concluding that the Alberico-Daubert stand~rd applies only to "expert
17 testimony that relies on scientific knowledge," rather than all forms 	of expert
18 	testimony); see also Lente, 2005-NMCA-111, 13 (noting that a district "court abuses
19 	its discretion when it exercises its discretion based on a misunderstanding of the
20 	law"). 	As there 	is no 	danger 	of unfair prejudice or misleading the jury that
27

1 substantially outweighs the probative value of Deputy Armijo's expert testimony,
2 we conclude that the district court abused its discretion in excluding this portion of
3 Deputy Armijo's expert testimony under Rule 11-403.
4 	III. 	CONCLUSION
5 	{35} 	We conclude that the State properly appealed to this Court, the district court
6 did not err in excluding Deputy Armijo's scientific expert testimony, and the district
7 court erred in excluding his non-scientific expert testimony. We therefore affirm in
8 part, reverse in part, and remand for further proceedings consistent with this opinion.
9 	{36}
10
11
IT IS SO ORDERED.
12 	WE CONC{1R:
J. MILES HANISEE, Judge
28