Introduction

This commentary analyzes the Wyoming Supreme Court’s decision in Davis v. State, an appeal from the denial of a motion to suppress arising from a traffic stop based on an alleged violation of Wyoming’s 100‑foot turn-signal statute, Wyo. Stat. Ann. § 31-5-217(b). The case presents a focused Fourth Amendment question: whether a police officer had reasonable suspicion to initiate a traffic stop based on his trained visual estimation that the driver engaged his turn signal less than 100 feet before turning, despite dashcam footage that did not definitively resolve the distance and a defense expert’s contrary time-distance calculation predicated on a constant speed.

Appellant Mark Davis, after being stopped for allegedly signaling too late, was found with methamphetamine and marijuana. He moved to suppress the evidence, arguing the stop was unlawful because he had signaled more than 100 feet in advance. The district court denied the motion, crediting the officer’s testimony and deeming the defense calculation unreliable due to its constant-speed assumption. On appeal, the Supreme Court affirmed, emphasizing deference to trial-level factual findings, the totality-of-circumstances analysis for reasonable suspicion, and the rule that the Fourth Amendment does not demand “perfect precision.”

Summary of the Opinion

• The Court held that a trained officer’s observation—here, that the driver activated his turn signal no more than approximately 20 feet before the turn—provided a particularized and objective basis to suspect a violation of § 31‑5‑217(b), thereby justifying the traffic stop under the Fourth Amendment.
• In reviewing a motion to suppress, appellate courts view the record in the light most favorable to the district court’s ruling and will not reweigh evidence or second-guess credibility determinations unless findings are clearly erroneous.
• Dashcam video that is not conclusive does not displace trial court fact-finding; the district court reasonably read the video in conjunction with the officer’s testimony.
• The defense expert’s time-distance calculation assumed a constant speed of 25 mph, an assumption the district court found unsupported by the record. Because the driver appeared to slow substantially before the intersection, the calculation did not undermine reasonable suspicion.
• Reasonable suspicion is a lower standard than probable cause and does not require “perfection”; it requires an objectively reasonable, articulable basis under the totality of the circumstances.

Bottom line: The stop was lawful. The evidence discovered thereafter was admissible. The denial of the motion to suppress was affirmed.

Analysis

The Statutory Framework: Wyoming’s 100-Foot Rule

Wyo. Stat. Ann. § 31-5-217(b) provides: “A signal of intention to turn right or left when required shall be given continuously during not less than the last one hundred (100) feet traveled by the vehicle before turning.” The statute sets a clear, objective distance threshold. In this case, the dispute centered on whether the officer had reasonable suspicion that the driver failed to meet that threshold—not whether the State proved a traffic violation beyond a reasonable doubt.

The Court relied on its prior articulation in Anderson v. State that the statute’s “plain language” requires signaling at least 100 feet before the turn, and that failure to signal within the required distance constitutes objective evidence of noncompliance (citing Peak v. State, an Indiana decision used for persuasive support).

Precedents Cited and Their Influence

• Terry v. Ohio, 392 U.S. 1 (1968):

  Provides the governing two-part inquiry for investigatory stops: (1) Was the initial stop justified? and (2) Was the officer’s conduct reasonably related in scope to the circumstances that justified the interference? Here, only the first prong was contested, and the Court applied Terry’s framework to determine whether the officer had reasonable suspicion to initiate the stop.

• Kennison v. State, 2018 WY 46 and Allgier v. State, 2015 WY 137:

  Reinforce that a traffic stop is a seizure under the Fourth Amendment and must be supported by reasonable suspicion. Allgier further emphasizes that the “ultimate touchstone” is reasonableness, and—invoking the U.S. Supreme Court’s Heien v. North Carolina—reminds us that “to be reasonable is not to be perfect.” This leeway is crucial in recognizing that officers may rely on trained visual estimations without precise measurements, provided their observations are objectively reasonable.

• Anderson v. State, 2023 WY 65:

  Construes § 31‑5‑217(b)’s plain meaning and acknowledges that a failure to signal the required distance is an objective indicator of a statutory violation. Anderson supports treating the 100-foot rule as an enforceable metric for reasonable suspicion when the facts reasonably suggest noncompliance.

• Elmore v. State, 2021 WY 41 and Venegas v. State, 2012 WY 136:

  Anchor the “particularized and objective basis” and “totality of the circumstances” tests. These cases emphasize that reasonable suspicion is a practical, fact-sensitive inquiry that accounts for an officer’s training and experience.

• Ramirez v. State, 2023 WY 70:

  Reiterates the Terry framework and the reasonableness requirement for both initiation and scope of a stop. In Davis, only initiation was at issue; the Court found it satisfied.

• Maestas v. State, 2018 WY 47:

  Confirms that an officer’s training, experience, and expertise are part of the totality analysis. The Court relied on this principle to credit the officer’s trained distance estimation.

• Hanson v. State, 2025 WY 56 and Marquez v. State, 2025 WY 61:

  Detail the standard of review applicable to suppression rulings: appellate courts view evidence in the light most favorable to the district court and defer to factual findings unless clearly erroneous. This deference was pivotal where the dashcam was inconclusive and credibility judgments mattered.

• Heien v. North Carolina, 574 U.S. 54 (2014) (as cited via Allgier):

  Supports the idea that the Fourth Amendment tolerates reasonable mistakes—of law in Heien, and by extension mistakes of fact—so long as the officer’s belief is objectively reasonable. In Davis, the Court did not find a mistake necessary to its analysis; it sufficed that the officer had an objectively reasonable basis.

• Peak v. State, 26 N.E.3d 1010 (Ind. Ct. App. 2015):

  Persuasive authority for the proposition that failing to signal within the required distance is objective evidence of noncompliance, bolstering the notion that such a violation can furnish reasonable suspicion for a stop.

Legal Reasoning

The Court’s reasoning proceeds in three interrelated steps: standard of review, the reasonable-suspicion standard, and application to the facts.

1. Standard of Review:

   Appellate courts defer to district-court fact-finding, especially on credibility, unless findings are clearly erroneous. The record is viewed in the light most favorable to the prevailing party (here, the State). Where video is not “obvious” or conclusive, the trial court’s synthesis of video and testimony stands unless palpably mistaken.

2. Reasonable Suspicion:

   Reasonable suspicion is a lower threshold than probable cause. It requires an articulable, particularized, objective basis to suspect a law violation, assessed under the totality of the circumstances. Officers’ training and experience matter. The Fourth Amendment’s reasonableness does not require perfect measurements or infallibility.

3. Application to the Facts:
   • The officer testified, based on five years’ policing and training in distance/speed estimation, that Davis activated his signal only “mere feet” from the intersection—no more than 20 feet before turning, well short of the 100-foot requirement.
   • Dashcam video was reviewed “numerous times” by the district court and was not decisive on the precise distance. However, considered alongside the officer’s testimony, it supported the conclusion that the officer possessed reasonable suspicion.
   • The defense expert’s estimate (293 feet) assumed the driver maintained 25 mph for eight seconds of signaling. The district court found that assumption implausible, given the obvious slowing and braking before the stop sign. Accepting that slowing undermined the constant-speed calculation, the district court discounted the expert’s conclusion.
   • Taking the record as a whole, the State met its burden to show, by a preponderance of the evidence, that the officer had reasonable suspicion of a § 31‑5‑217(b) violation. Notably, the State did not have to prove the actual distance or a completed violation with precision; it needed to show only an objectively reasonable basis to suspect a violation.

Evidentiary Assessment: Officer Estimation vs. Dashcam vs. Defense Calculation

The case highlights three common evidentiary modalities in traffic-stop litigation:

• Trained Officer Estimation: The Court recognized that officers frequently estimate distances and speeds in real time and that such estimations—when grounded in training and experience—can be sufficiently reliable to support reasonable suspicion.
• Dashcam Footage: Video evidence is powerful but not always dispositive. Where video does not unambiguously resolve key facts (e.g., the precise moment of activation relative to a fixed point), it is weighed with other evidence, not substituted for it.
• Defense Time-Distance Models: Mathematical models premised on assumed speeds can be probative but are vulnerable if the underlying assumptions are unsupported. Here, the assumption of a steady 25 mph conflicted with the observed deceleration approaching a stop sign, undercutting the model’s reliability.

What the Court Did Not Decide

• Scope and duration of the detention: Not challenged on appeal; the Court addressed only the initiation of the stop.
• Lawfulness of subsequent search(s): The defendant did not contest the search or arrest on appeal; admissibility followed from the lawfulness of the stop.
• Per se rules about dashcam primacy: The Court did not hold that video must control over trained observations; instead, it reaffirmed holistic weighing of evidence.
• Exact distance measurement requirements: The Court expressly rejected any need for exactitude at the reasonable-suspicion stage.

Key Holdings and Doctrinal Takeaways

• Reasonable suspicion to stop for a § 31‑5‑217(b) violation can be established by a trained officer’s credible estimation that a driver activated a turn signal less than 100 feet before turning, even if the dashcam video is inconclusive.
• Defense calculations that assume constant speeds near intersections are suspect where the record shows deceleration; courts may discount such models absent corroborating speed data.
• At suppression hearings, the State’s burden is to show—by a preponderance—that the officer had reasonable suspicion; it need not prove the violation occurred or supply precise measurements.
• Appellate courts will not reweigh evidence or disturb credibility findings without clear error; ambiguous video does not displace trial court inferences.
• The “reasonableness, not perfection” principle—rooted in Allgier and Heien—applies to traffic stops grounded in trained observations and situational judgment.

Impact and Practical Implications

For Law Enforcement

• Document training and experience in estimating distances and speeds; courts will consider it within the totality analysis.
• Describe contextual cues that support estimation (e.g., brake lights, deceleration, proximity to fixed landmarks like stop signs).
• Use dashcam footage to corroborate, but do not rely on it alone; when video is inconclusive, detailed contemporaneous observations remain critical.

For Defense Counsel

• Avoid distance/time models predicated on constant speed at intersections; seek objective corroboration (e.g., mapping measurements, speed data from the event recorder, video time stamps calibrated to known distances).
• When video is ambiguous, focus on undermining the officer’s training-specific estimation competencies or highlighting environmental factors that could distort perception.
• Consider on-site measurements and demonstrative exhibits to show distances between landmarks and activation points where feasible.

For Trial Courts

• Expressly articulate how video evidence integrates with testimonial evidence; explain why particular assumptions (like constant speed) are or are not adopted.
• Anchor credibility findings in concrete record references (e.g., observed deceleration, number of blinks, brake-light illumination over time).
• Clarify that the reasonable-suspicion question concerns an officer’s objectively reasonable belief, not exact compliance measurements.

For Fourth Amendment Doctrine in Wyoming

• Davis reinforces a pragmatic approach: reasonable suspicion for technical traffic infractions may rest on trained observations supported by but not dictated by video.
• The decision may reduce the perceived necessity for precise, instrument-based measures in suppression litigation involving distance-based infractions, so long as the officer’s account is credible and contextually grounded.
• It underscores continued deference to district courts where the record is mixed or ambiguous, shaping appellate expectations in dashcam-era suppression appeals.

Complex Concepts Simplified

• Reasonable Suspicion vs. Probable Cause:

  Reasonable suspicion is a modest threshold: specific, articulable facts that suggest a law might be violated. Probable cause is stronger: facts that would lead a reasonable person to believe a violation probably occurred. Traffic stops require reasonable suspicion, not probable cause.

• Preponderance of the Evidence at Suppression:

  At a suppression hearing, the State must show it is more likely than not that the officer had reasonable suspicion. This standard governs the court’s decision on the motion; it does not convert the hearing into a mini-trial on whether the traffic infraction actually occurred.

• Standard of Review—“Clearly Erroneous” and Deference:

  Appellate courts don’t redo fact-finding. They defer to the trial court’s findings unless left with the firm conviction a mistake was made. Credibility judgments and interpretations of ambiguous video are rarely overturned.

• Totality of the Circumstances:

  No single fact decides the case. Courts look at the whole picture—officer training, observations, video, and context—rather than isolating one variable (like seconds of signal or posted speed) in a vacuum.

• “Reasonableness, Not Perfection”:

  Fourth Amendment law recognizes that real-world policing involves estimation and judgment. The Constitution requires reasonable decision-making, not laboratory-level precision.

• 100-Foot Turn-Signal Rule:

  Wyoming law requires drivers to signal continuously for at least the last 100 feet before turning. A credible basis to think a driver failed to do so justifies a stop; proving the exact footage is unnecessary at the reasonable-suspicion stage.

Conclusion

Davis v. State clarifies and cements a practical rule for Wyoming suppression law: a trained officer’s credible distance estimation, even when dashcam evidence is inconclusive and defense models rely on questionable speed assumptions, can establish reasonable suspicion for a turn-signal infraction under § 31‑5‑217(b). The Court’s decision reinforces three pillars—deference to trial courts on fact-finding, the totality-of-circumstances approach to reasonable suspicion, and the “reasonableness, not perfection” standard rooted in Fourth Amendment jurisprudence.

The case will resonate in future challenges to traffic stops premised on distance-sensitive statutes. It encourages careful articulation of observational bases by law enforcement, cautions against over-reliance on constant-speed calculations by the defense, and reminds trial courts to integrate video and testimony into a coherent, fact-sensitive analysis. Above all, Davis situates reasonable suspicion where the Constitution intends it to be: in the realm of grounded, common-sense police judgments, measured after the fact with respect for both context and credibility.