State v. Alvarez‑Soto: Arizona Rejects Independent Appellate Review of Video Evidence and Upholds Traffic Stops Based on Objectively Reasonable Mistakes of Law

I. Introduction

The Arizona Supreme Court’s decision in State of Arizona v. Asalia Guadalupe Alvarez‑Soto (No. CR‑24‑0281‑PR, filed Nov. 28, 2025) is a significant opinion at the intersection of Fourth Amendment law, traffic enforcement, and appellate procedure. It does two important things:

It holds that an officer had reasonable suspicion to initiate a traffic stop based on an arguably ambiguous “keep right” statute, thereby embracing and applying the United States Supreme Court’s doctrine allowing objectively reasonable mistakes of law (Heien v. North Carolina) in the reasonable‑suspicion context.
It disapproves State v. Sweeney, which had endorsed “independent” de novo review of video evidence on appeal, and reaffirms that Arizona appellate courts must defer to trial court fact‑finding even when the evidence is captured on video.

The case arises from a highway stop on Interstate 10 in Pinal County that ultimately led to the discovery of fifty‑five pounds of marijuana. The defendant moved to suppress the evidence as the fruit of an unlawful seizure, and her appeal raised both substantive Fourth Amendment questions and a procedural question about how appellate courts should review video evidence contained in the record.

The Supreme Court affirmed the trial court’s denial of the suppression motion, vacated the Court of Appeals’ contrary decision, and remanded for further proceedings on a separate, unresolved question: whether the trooper unlawfully prolonged the traffic stop.

II. Factual and Procedural Background

A. The stop on Interstate 10

On December 14, 2018, Trooper Ashton Shewey of the Arizona Department of Public Safety was patrolling I‑10 in Pinal County. He observed a 2007 Chevrolet Malibu traveling in the middle lane. Using his license‑plate reader, he learned the car was newly registered in Nogales and had recently crossed the U.S.–Mexico border multiple times. Based on his narcotics‑interdiction experience, he regarded such Malibus as potential “company vehicles” used by drug‑trafficking organizations.

Interested but awaiting an objective infraction, he followed the vehicle, driven by Asalia Alvarez‑Soto, for “several minutes” and “several miles.” He saw the car initially traveling approximately 78 mph in a 75 mph zone, then slowing to around 70 mph. During this time, a red SUV in the right lane passed her on the right. Defendant remained in the middle lane and did not move right.

Trooper Shewey testified that, under his training and departmental practice, he understood A.R.S. § 28‑721(B) to require slower traffic to keep right, and that troopers routinely stopped vehicles in the middle lane being passed on the right as violators of that statute. Relying on this understanding, he initiated a traffic stop for a suspected violation of § 28‑721(B) (failure of slower traffic to drive in the right lane).

B. The canine sniff and seizure of marijuana

During the stop, while preparing a written warning, Shewey engaged Alvarez‑Soto about her travel plans and sought consent to search the car. She refused. He then requested consent to conduct a canine sniff of the vehicle with his dog, Chili; this time, she consented.

Chili, trained to detect narcotics, alerted to the driver’s side of the car. A resulting search uncovered a suitcase containing fifty‑five pounds of marijuana in the trunk. Alvarez‑Soto was arrested and charged with possession and transportation of marijuana for sale.

C. Suppression motion and trial

Prior to trial, the defendant moved to suppress all evidence seized during the stop, arguing, among other things, that Trooper Shewey lacked reasonable suspicion to believe she had violated § 28‑721(B). The trial court held an evidentiary hearing at which the trooper described:

His training and experience in traffic enforcement and drug interdiction;
His familiarity with § 28‑721(B) and its enforcement on I‑10;
His observations of the defendant’s speed and lane position; and
The dashcam video documenting the events.

The dashcam video captured the defendant driving in the middle lane and the red SUV passing her on the right. After hearing evidence, the trial court found the stop justified and denied the suppression motion. A jury convicted Alvarez‑Soto on both marijuana counts, and she received concurrent five‑year prison terms.

D. The Court of Appeals decision

On appeal, Division Two of the Court of Appeals, in a split opinion, vacated the convictions and held that Trooper Shewey lacked reasonable suspicion to conduct the stop under § 28‑721(B). The majority concluded that his interpretation of the statute “cast too wide a net” and, if accepted, would subject drivers to “virtually random seizures.”

The dissent in the Court of Appeals viewed the defendant’s conduct as a continued, not momentary, statutory violation and would have upheld the stop.

The State petitioned for review. The Arizona Supreme Court granted review to address both the reasonable‑suspicion issue and the proper standard of appellate review for video evidence, characterizing the case as presenting a recurring issue of statewide importance.

III. Summary of the Supreme Court’s Opinion

Vice Chief Justice Lopez, writing for a unanimous Court, reached two key holdings:

Reasonable suspicion for the traffic stop. The trial court did not abuse its discretion in denying the suppression motion. Viewing the evidence in the light most favorable to sustaining the ruling, the trooper had at least reasonable suspicion, under the totality of the circumstances, to believe that defendant was violating § 28‑721(B)’s requirement that vehicles traveling “less than the normal speed of traffic” drive in the right‑hand lane. Even if his interpretation of that statute was debatable or imperfect, it was an objectively reasonable view of an ambiguous provision and thus sufficient to support reasonable suspicion under the Fourth Amendment.
Standard of review for video evidence; disapproval of Sweeney. The Court held that State v. Sweeney, 224 Ariz. 107 (App. 2010), does not correctly state the appellate standard of review for video evidence. Appellate courts may not conduct “independent” de novo review of video evidence or substitute their own view of recorded events for the trial court’s factual findings. Instead, the standard from State v. Adair applies to all suppression rulings regardless of evidentiary format: appellate courts review factual findings for abuse of discretion (deference if supported by the record) and review legal conclusions, such as whether those facts establish reasonable suspicion, de novo.

Having so held, the Court:

Affirmed the trial court’s denial of the suppression motion as to the initial stop;
Vacated the Court of Appeals’ contrary opinion; and
Remanded to the Court of Appeals solely to consider an unresolved claim: whether Trooper Shewey unlawfully extended the duration of the traffic stop (a separate Fourth Amendment issue not addressed in this opinion).

IV. Detailed Analysis

A. Precedents and Authorities Cited

1. Fourth Amendment and reasonable suspicion

Terry v. Ohio, 392 U.S. 1 (1968), and United States v. Sokolow, 490 U.S. 1 (1989).
These cases establish that officers may briefly detain individuals for investigative purposes if they have “reasonable suspicion supported by articulable facts” that criminal activity “may be afoot,” even short of probable cause. The Court cites them to underscore that a traffic stop requires only this modest threshold, not proof of an actual violation.
Kansas v. Glover, 589 U.S. 376 (2020), and Prado Navarette v. California, 572 U.S. 393 (2014).
These decisions define reasonable suspicion as a “considerably less” demanding standard than preponderance of the evidence or probable cause, emphasizing that reasonable suspicion tolerates some uncertainty and does not require ruling out innocent explanations.
Carpenter v. United States, 585 U.S. 296 (2018).
Cited as a recent reference to the Fourth Amendment’s protection against unreasonable searches and seizures, anchoring the analysis in modern Fourth Amendment doctrine.

2. Arizona’s reasonable‑suspicion framework

State v. Adair, 241 Ariz. 58 (2016).
The Court relies heavily on Adair for the standard of review: denial of a suppression motion is reviewed for abuse of discretion; courts consider only the evidence presented at the suppression hearing; and factual findings are reviewed deferentially while legal conclusions (e.g., whether those facts amount to reasonable suspicion) are reviewed de novo. Adair also serves as the anchor for rejecting Sweeney’s “independent review” of video evidence.
State v. Evans, 237 Ariz. 231 (2015).
Cited for the two‑step approach: appellate courts defer to facts found by the trial court but independently decide whether those facts establish reasonable suspicion. It also reiterates that only a “minimal level of objective justification” is required for a stop.
State v. Mitcham, 258 Ariz. 432 (2024), and State v. Thompson, 252 Ariz. 279 (2022).
These cases confirm that, on appeal from a suppression ruling, the reviewing court considers only the evidence presented at the suppression hearing, not trial evidence or later‑developed facts.
A.R.S. § 28‑1594.
This statute codifies reasonable suspicion in the traffic context: a peace officer may stop and detain a person “as is reasonably necessary” to investigate an actual or suspected traffic violation. The Court uses it to show that reasonable suspicion is explicitly built into Arizona’s traffic‑enforcement regime.

3. Mistakes of law and the ambiguity of traffic statutes

Heien v. North Carolina, 574 U.S. 54 (2014).
Central to the Court’s reasoning, Heien holds that a reasonable mistake of law can still support reasonable suspicion, so long as the officer’s interpretation is objectively reasonable. Justice Kagan’s concurrence (quoted by the Arizona Supreme Court) clarifies that this applies where a statute’s application “requires hard interpretive work.” The phrase “normal speed of traffic” in § 28‑721(B), lacking a quantitative metric, fits this category.
State v. Stoll, 239 Ariz. 292 (App. 2016).
An Arizona application of Heien, recognizing that an objectively reasonable mistake of law may sustain reasonable suspicion. The Court invokes it to support giving officers “fair leeway” in interpreting ambiguous statutes in real time.
Brinegar v. United States, 338 U.S. 160 (1949).
Cited via Heien for the proposition that the Fourth Amendment allows for some mistakes by government officials, granting them “fair leeway” in law enforcement.
State v. Weakland, 246 Ariz. 67 (2019).
In Weakland, the Arizona Supreme Court applied the good‑faith exception to the exclusionary rule, holding that it is unreasonable to require police to anticipate shifts in the law that even trial and appellate courts did not foresee. In Alvarez‑Soto, this case illustrates the principle that officers should not be penalized for failing to anticipate how judges will ultimately resolve contested statutory interpretations.
State v. Livingston, 206 Ariz. 145 (App. 2003).
The Court of Appeals relied on Livingston to argue that certain traffic statutes include built‑in flexibility. There, § 28‑729(1) requires drivers to remain “as nearly as practicable” within a single lane; the Court of Appeals had construed this as showing legislative intent to avoid penalizing “brief, momentary, and minor deviations.” The Arizona Supreme Court distinguishes Livingston as factually different and, more importantly, not controlling on what the Fourth Amendment requires for reasonable suspicion.

4. Pretext, subjective motive, and objective justification

Jones v. Sterling, 210 Ariz. 308 (2005).
The Court uses Jones to emphasize that the subjective motivations of an officer in making a traffic stop are irrelevant under the Fourth Amendment, so long as the stop meets “normal” Fourth Amendment standards. This allows the Court to bracket the trooper’s interest in drug interdiction and his knowledge of border‑crossing patterns as non‑dispositive of the stop’s constitutionality.
State v. Sweeney, 224 Ariz. 107 (App. 2010).
Cited in two very different ways:
- The Supreme Court relies on a portion of Sweeney recognizing that generalized factors that do not reliably distinguish suspects from innocent people cannot alone create reasonable suspicion.
- More centrally, the Court disapproves Sweeney’s separate, novel suggestion that appellate courts may conduct “independent” de novo review of video evidence.

5. Appellate standards of review and video evidence

Danielson v. Evans, 201 Ariz. 401 (App. 2001).
Sweeney had cited Danielson as support for its video‑review approach. The Supreme Court clarifies that Danielson involved statutory interpretation and a divorce decree, both issues reviewed de novo; it did not address video evidence or fact‑finding standards.
State v. McCoy, 692 N.W.2d 6 (Iowa 2005).
Another case invoked by Sweeney. The Iowa Supreme Court happened to view video evidence in the course of reviewing an ineffective‑assistance claim, but applied de novo review because that is the standard for such claims, not because the evidence was on video. The Arizona Supreme Court rejects the use of McCoy to justify an across‑the‑board de novo standard for video recordings.
State v. Steinle, 239 Ariz. 415 (2016), and Beech Aircraft Corp. v. Rainey, 488 U.S. 153 (1988).
These cases acknowledge that the “total tenor and effect” of evidence, including video, may depend on context and accompanying testimony. The Supreme Court uses them to underscore that trial courts are better positioned than appellate courts to interpret what a video shows in light of the full evidentiary record.

B. The Court’s Legal Reasoning on Reasonable Suspicion

1. Framing the issue: constitutional reasonableness, not statutory guilt

A central analytic move in the opinion is the Court’s insistence on properly framing the question. The Court of Appeals asked whether, as a matter of statutory interpretation, § 28‑721(B) compels a driver in the middle lane to move right if she is passed by a single vehicle on the right, absent evidence of that vehicle’s speed. The Supreme Court characterizes this as a misframing of the issue.

For purposes of the Fourth Amendment, the key question is not:

Did the defendant in fact violate § 28‑721(B)?

but rather:

Did the officer have a particularized, objective basis—i.e., reasonable suspicion—to believe that a violation of § 28‑721(B) might be occurring?

Whether a traffic court would ultimately find the defendant guilty of a civil infraction under the statute is a separate question. A seizure can be reasonable under the Fourth Amendment even if it later turns out that no violation occurred or the statute is interpreted more narrowly than the officer believed.

2. The ambiguity of “normal speed of traffic”

The operative statutory language provides that:

On all roadways, a person driving a vehicle proceeding at less than the normal speed of traffic at the time and place and under the conditions then existing shall drive the vehicle in the right‑hand lane then available for traffic . . . .

The Court highlights that the phrase “normal speed of traffic”:

Provides no numerical or quantitative standard;
Is open to multiple plausible interpretations; and
Was in fact construed differently by the Court of Appeals’ majority and dissent, as well as by the litigants.

The very existence of such divergent views among judges after extensive briefing and “hard interpretive work” strongly suggests, under Heien, that the statute is ambiguous enough that an officer’s real‑time, literal reading can still be objectively reasonable, even if not ultimately adopted by courts.

3. Applying Heien: objectively reasonable mistakes of law

Drawing on Heien and Stoll, the Court holds that reasonable suspicion can rest on an objectively reasonable mistake of law. To be “objectively reasonable,” a mistake must concern a statute whose meaning or application is legitimately debatable—not an interpretation that ignores clear statutory text.

Here, Shewey:

Observed the defendant slow from 78 mph to around 70 mph in a 75 mph zone while in the middle lane;
Witnessed a right‑lane vehicle (the red SUV) pass her on the right; and
Noted that she did not move into the right lane after being passed, despite traveling below both the speed limit and, in his judgment, “the normal speed of traffic” in that stretch of I‑10.

Combined with his training and the common enforcement practice he described, he concluded that she was “traveling less than the normal speed of traffic” and violating § 28‑721(B). Even if another court would read the statute differently in a later civil adjudication, that real‑time assessment, the Court holds, was at least an objectively reasonable interpretation of an ambiguous law.

Crucially, the Court emphasizes that:

If trial and appellate judges cannot reach consensus on the statute’s proper application even after exhaustive statutory analysis, we cannot deem an officer’s real‑time literal interpretation of the law to be objectively unreasonable.

4. Rejecting the Court of Appeals’ “flexibility” requirement

The Court of Appeals majority had suggested that officers must account for a judicially perceived legislative intent to provide “some measure of flexibility” in traffic statutes, citing Livingston and its interpretation of “as nearly as practicable” language in another statute. From this, it inferred that only prolonged or non‑trivial violations should generate reasonable suspicion.

The Supreme Court rejects this approach on several grounds:

Factual distinction. The Court agrees with the Court of Appeals dissent that the record reflects a continued, not momentary, deviation from § 28‑721(B) (the defendant remained in the middle lane over several minutes and miles while traveling slower than traffic).
Different statute. Livingston interpreted a different statute, concerning lane discipline (“as nearly as practicable” within a single lane), and did not speak to § 28‑721(B)’s “normal speed of traffic” language.
Fourth Amendment threshold. Most importantly, the Fourth Amendment does not require officers to incorporate judicially articulated “flexibility” into their real‑time understanding before making an investigatory stop. It requires only a particularized and objective basis to suspect that a violation “may be afoot.”

Thus, even if the legislature intended some flexibility, and even if a traffic court might excuse minor deviations under § 28‑721(B), that does not mean an officer’s contrary, but reasonable, understanding fails the reasonable‑suspicion standard.

5. Rejecting the “forced speeding” concern

The Court of Appeals worried that the trooper’s reading of § 28‑721(B) would effectively require drivers to exceed the speed limit to avoid being stopped—if “normal speed of traffic” exceeds the posted limit. The Supreme Court dismisses this concern as a mischaracterization of the record, pointing out that the defendant had “multiple ways” to comply with all laws, such as:

Moving into the right lane and falling in behind the faster right‑lane vehicle; or
Maintaining the speed limit while adjusting lane position to avoid impeding faster right‑lane traffic.

The Court stresses that the defendant was not penalized “solely for being passed,” but for a combination of factors: slowing below the limit in the middle lane, being passed on the right, and not adjusting lane position thereafter.

6. The role of generalized “drug courier” indicators

The trooper’s background investigation—learning that the car was a newly registered Malibu out of Nogales with numerous border crossings—matched his narcotics profile of a “company vehicle.” The Court is careful, however, to emphasize that:

Such generalized factors, “shared by many lawful motorists,” are too nonspecific to create reasonable suspicion on their own; and
The State did not attempt to justify the stop based solely on these considerations.

Citing Sweeney, the Court reiterates that factors which “do not reliably distinguish between suspect and innocent behaviors” cannot alone establish reasonable suspicion. But under Jones v. Sterling, the officer’s subjective motives—to investigate drug trafficking using these indicators—are irrelevant as long as there was an objectively reasonable traffic basis for the stop.

7. Totality of the circumstances and conclusion on reasonable suspicion

Synthesizing all this, the Court holds that, under the totality of the circumstances:

The officer’s interpretation of § 28‑721(B) was objectively reasonable, given its ambiguity and his training and experience;
His observations supported a particularized suspicion that defendant was traveling “less than the normal speed of traffic” in the middle lane; and
His conduct reflected professional judgment rather than arbitrary or random enforcement.

Therefore, the trial court did not abuse its discretion in denying the suppression motion on the basis that the initial stop was lawful.

C. The Court’s Legal Reasoning on Video Evidence and Standards of Review

1. The Sweeney departure and its rationale

State v. Sweeney had posited that when the evidence includes a video recording, an appellate court is “in no better position” than the trial court to evaluate it, and should therefore conduct an “independent” review. This effectively meant that appellate courts could:

Re‑interpret the video without deference to the trial court’s factual findings; and
Function as an additional fact‑finder whenever the evidence was on video.

Sweeney relied on Danielson and McCoy to support this innovation. The Supreme Court in Alvarez‑Soto finds both cited cases inapposite:

Danielson involved purely legal questions (statutory interpretation and a decree), which are always reviewed de novo and did not concern video.
McCoy applied de novo review because ineffective‑assistance claims are reviewed de novo, not because evidence happened to be in video form.

2. Reaffirming the Adair standard

The Court reaffirms that Adair already provides a complete framework governing suppression rulings, including those with video evidence:

Factual findings (what happened, how fast, how long, where, etc.) are reviewed for abuse of discretion. Appellate courts defer to the trial court if those findings are reasonably supported by the record.
Legal conclusions (e.g., whether the found facts amount to reasonable suspicion, probable cause, or a constitutional violation) are reviewed de novo.

This two‑tiered standard applies irrespective of whether the evidence is testimonial, documentary, photographic, or recorded on video.

3. Why trial courts remain superior fact‑finders, even with video

The Court rejects the premise that a “purely visual record” puts appellate courts in as good a position as trial courts. It notes that the trial judge:

Sees and hears live testimony explaining what the video depicts;
Receives contextual information about perspective, timing, and events outside the frame;
Evaluates witness credibility and demeanor; and
Integrates video evidence with other evidence in the record.

By contrast, an appellate court reviews a cold record. Allowing it to redraw factual conclusions from a video would:

“Erase” the distinction between trial and appellate functions;
Encourage reweighing of evidence under the guise of “independent” video review; and
Undermine uniformity by creating a separate, more intrusive standard whenever evidence happens to be recorded.

4. When can an appellate court override trial court factual findings based on a video?

The Court acknowledges that appellate courts can, and sometimes must, rely on video to correct factual findings that are clearly unsupported by the record. Its example:

If a trial court finds that a car was blue, but the video plainly shows that it was red, the appellate court may correct that error.

This is not a new standard. Rather, it fits comfortably within the abuse‑of‑discretion/clearly erroneous framework:

Appellate courts ensure that findings have a reasonable evidentiary basis; and
If a finding is flatly contradicted by indisputable video evidence, it is not “supported by the record.”

However, where a video is open to differing interpretations or requires contextual testimony—for example, assessing the reasonableness of timing, distances, or the import of subtle conduct—appellate courts must defer to the trial court’s evaluation if it is reasonably supported.

5. Disapproval of Sweeney and unification of the standard

The Court explicitly disapproves Sweeney “to the extent [it] suggests that appellate courts may engage in de novo or ‘independent’ review of video evidence.” It cites academic commentary to the effect that the format of evidence (audio‑video vs. live) should not change the standard of review. Factual findings remain reviewed for clear error/abuse of discretion, and legal conclusions remain reviewed de novo.

This unification:

Reinforces the trial court’s role as the primary fact‑finder;
Maintains consistency across evidence types; and
Prevents piecemeal erosion of deference whenever technology captures the events at issue.

V. Complex Legal Concepts Simplified

A. Reasonable suspicion vs. probable cause

Reasonable suspicion is a low threshold. It requires specific, articulable facts that, taken together with rational inferences, suggest that criminal activity or a traffic violation may be occurring. It is more than a mere “hunch” but less than a “more likely than not” belief.
Probable cause requires a higher degree of certainty: facts and circumstances sufficient to warrant a reasonable belief that a crime has been committed and that the person or place to be searched is involved. It is required for arrests and search warrants, but not for the brief investigative stop at issue here.

B. Mistake of law and Heien

Traditionally, “ignorance of the law is no excuse” for defendants. In the Fourth Amendment context, however, Heien recognizes that if a statute is legitimately ambiguous and courts themselves disagree over its meaning, an officer’s mistaken but reasonable interpretation can still justify a stop.

In practical terms:

If a statute clearly says “no headlights required during daylight,” an officer who stops someone in daylight for not having headlights is making an unreasonable mistake of law—no reasonable suspicion.
If a statute uses vague language like “normal speed of traffic,” and judges later disagree on its precise meaning, an officer who adopts one reasonable reading of that language can have reasonable suspicion even if another court later interprets it differently.

C. The exclusionary rule and good‑faith principles

The exclusionary rule allows courts to suppress evidence obtained in violation of the Fourth Amendment to deter unlawful police conduct. But courts also recognize a good‑faith exception: if officers reasonably rely on a statute, warrant, or precedent that is later invalidated or changed, suppression is often not required.

While Alvarez‑Soto is not formally a good‑faith case, it draws on similar reasoning (as in Weakland): it is unfair to fault officers for failing to predict how courts will ultimately interpret ambiguous laws.

D. Standards of appellate review

Abuse of discretion / clear error (for facts).
Appellate courts defer to trial courts on factual questions unless the findings lack reasonable support in the record. This respects the trial judge’s superior ability to weigh evidence and assess credibility.
De novo review (for law).
Appellate courts independently decide legal questions, such as the interpretation of statutes or constitutional standards. They owe no deference to the trial court’s legal conclusions.
Application in suppression cases.
In suppression rulings, courts follow a hybrid approach:
- Defer to the trial court on “what happened” (facts), if supported; and
- Review independently whether those facts satisfy legal standards like reasonable suspicion or probable cause.

E. Pretext stops and subjective motivation

A “pretextual” stop occurs when an officer uses a minor traffic violation as a justification to investigate unrelated suspected criminal activity (e.g., drug trafficking). Under current Fourth Amendment doctrine, such stops are constitutionally permissible so long as there is an objectively reasonable basis—such as a traffic infraction—for the stop. The officer’s subjective motives are irrelevant.

Alvarez‑Soto follows this approach: while Trooper Shewey clearly had drug‑interdiction motives and relied on broad “drug courier” indicators to decide to follow the car, his decision to stop was constitutional because it rested on an objectively reasonable suspicion of a traffic violation.

F. Video evidence and appellate review

The temptation with video evidence is to think: “The appellate court can just watch the same video and decide for itself.” But the Supreme Court emphasizes that:

Video rarely speaks for itself; it often requires explanatory testimony and contextual understanding;
The trial judge has the benefit of live testimony and can better resolve disputes about what the video shows; and
Appellate courts must therefore treat video like any other evidence—relying on it to see if factual findings are supported, but not re‑trying the facts.

VI. Practical and Doctrinal Impact

A. Impact on traffic enforcement and Fourth Amendment practice in Arizona

Low threshold for traffic stops reaffirmed.
The decision reinforces that Arizona officers may initiate traffic stops based on minimal objective indications of a possible traffic violation. They need not resolve statutory ambiguities on the roadside; it is enough that their interpretation is objectively reasonable.
Ambiguous traffic statutes still support reasonable suspicion.
The Court’s application of Heien to § 28‑721(B) signals that other ambiguous traffic provisions can legitimately serve as bases for stops, even if courts later resolve those ambiguities in a way that would favor a defendant in a traffic adjudication.
Pretextual drug‑interdiction stops remain viable.
The opinion implicitly endorses the continued use of traffic violations as gateways to narcotics investigations. While generalized drug‑courier indicators alone are insufficient for reasonable suspicion, they can guide officers’ discretionary decisions about whom to follow and when to look for objective traffic infractions.
Importance of officer training and testimony.
The Court repeatedly references the trooper’s training, experience, and the common practice of enforcing § 28‑721(B) in similar circumstances. For future litigation, law‑enforcement agencies and prosecutors will likely emphasize detailed training records and on‑the‑ground practices to demonstrate the objective reasonableness of officers’ interpretations.
Defense strategies: focusing on “objective reasonableness” and totality.
Defense counsel will need to:
- Argue that an officer’s legal interpretation is not objectively reasonable given statutory text and context; and
- Highlight alternative innocent explanations and the limited nature of the observed conduct to show that, under the totality of circumstances, a stop was based on a mere hunch.

B. Impact on appellate practice and use of video evidence

No special appellate standard for video.
Appellate courts in Arizona must treat video evidence as they treat all other evidence. They may use video to test whether factual findings have support, but may not conduct de novo fact‑finding merely because the record is visual.
Trial courts: build a clear record around video.
Given the continued deference to trial‑court factual findings, trial judges and litigants must develop a robust record:
- Having witnesses explain what the video shows and why it matters;
- Clarifying distances, speeds, timing, and angles not obvious from the recording; and
- Expressly stating factual findings about what the video depicts.
Appellate briefing: frame challenges within the abuse‑of‑discretion standard.
Parties can still argue that a trial court misinterpreted a video, but must couch those arguments as claims that the findings are clearly unsupported by the record, not as invitations for the appellate court to “independently” re‑view the video.
Uniformity across evidentiary formats.
The opinion promotes doctrinal clarity by ensuring that the standard of review does not fluctuate with technology. As body‑worn cameras, dashcams, and surveillance footage become more ubiquitous, this clarification helps stabilize appellate review practices.

C. Unresolved issue on remand: prolongation of the stop

The Supreme Court expressly leaves open a critical question: whether Trooper Shewey unlawfully extended the duration of the stop to conduct the canine sniff. This question implicates the United States Supreme Court’s decision in Rodriguez v. United States, which limits how long a traffic stop may be extended for unrelated criminal investigations absent additional reasonable suspicion.

On remand, the Court of Appeals must decide:

Whether the timing and sequence of events (warning, questions, refusal of search, consent to sniff, deployment of the dog) complied with constitutional limits; and
Whether any extension, if it occurred, was supported by independent reasonable suspicion of drug activity.

Thus, while Alvarez‑Soto resolves the lawfulness of the initial seizure and clarifies key doctrines, the overall suppression question in this case will not be fully settled until the remand proceedings conclude.

VII. Conclusion

State v. Alvarez‑Soto is a consequential decision in Arizona criminal procedure and Fourth Amendment law. On one axis, it embraces the Heien doctrine, holding that officers may base traffic stops on objectively reasonable interpretations of ambiguous statutes, even if courts later read those statutes differently. This reinforces the low threshold for reasonable suspicion and provides “fair leeway” to officers enforcing complex traffic codes in real time.

On another axis, the Court decisively rejects Sweeney’s invitation to treat video evidence as a special category warranting de novo appellate review. By reaffirming the Adair framework, the Court safeguards the trial court’s central role as fact‑finder and preserves a uniform standard of review across all evidentiary formats.

The opinion thus clarifies:

That constitutional reasonableness is distinct from ultimate civil or criminal liability under a traffic statute;
That ambiguous traffic laws can still provide a foundation for reasonable suspicion when interpreted reasonably by trained officers; and
That appellate courts, even in a video‑rich era, must defer to trial‑court fact‑finding unless clearly unsupported by the record.

In the broader legal landscape, Alvarez‑Soto will shape how Arizona courts evaluate traffic stops, how officers articulate their understanding of traffic laws, and how appellate courts handle the increasingly ubiquitous presence of video in suppression litigation. It stands as a key precedent at the juncture of substantive Fourth Amendment doctrine and the procedural law of appellate review.