Introduction

In United States v. Brown, No. 25-6004 (10th Cir. Sept. 8, 2025), a Tenth Circuit panel affirmed the denial of a suppression motion following a late-night traffic stop on an Oklahoma interstate that culminated in the impoundment of the defendant’s vehicle and the discovery of multiple firearms. The opinion—an unpublished order and judgment—clarifies several recurring Fourth Amendment questions:

• What actions an officer may take during a traffic stop without unlawfully prolonging it.
• When a vehicle may be impounded under the community-caretaking exception without resort to the Sanders factors.
• How a “community-caretaking search” of an impounded vehicle differs from an inventory search—and how appellate waiver can cement the result.

The defendant, Thomas Lamare Brown, was stopped for improper use of fog lights. After the stop escalated—featuring the sighting of a large knife, what appeared to be a holster clip, and Brown briefly fleeing and returning across the interstate—the officer impounded a vehicle that was parked mere inches from the right-hand lane. A search while awaiting the tow revealed two pistols, two rifles, and ammunition. A jury convicted Brown of being a felon in possession; he received a 188-month sentence under the Armed Career Criminal Act. On appeal, he challenged the stop’s scope, the impoundment, and the search. The Tenth Circuit affirmed.

Summary of the Opinion

• Stop duration and scope: Asking Brown to step out to view the fog lights and to accompany the trooper to the patrol car did not unlawfully prolong the stop. The first action directly related to the mission of the stop; the second did not add time as a factual matter and, independently, was justified by officer-safety interests inherent in the traffic-stop mission.
• Impoundment: The vehicle’s position—“just inches” from the fog line on a heavily trafficked interstate after midnight—posed a public-safety hazard. Under South Dakota v. Opperman and recent Tenth Circuit authority, the community-caretaking doctrine permitted impoundment. Because the vehicle impeded traffic/posed a safety threat, the five Sanders factors did not apply. The record did not support a claim of pretext, and mixed motives would not invalidate the impoundment in any event.
• Search of the vehicle: The district court upheld the search as a valid community-caretaking search based on a reasonable belief a gun was in the car. On appeal, Brown argued only against the inventory-search rationale and did not challenge the caretaking rationale. That omission constituted waiver, and the search was therefore affirmed.
• Disposition: Conviction affirmed; suppression denied.

Standard of review: The court viewed the evidence in the light most favorable to the government, accepted district court factual findings absent clear error, and reviewed the ultimate Fourth Amendment reasonableness de novo. See United States v. Baker, 108 F.4th 1241, 1246 (10th Cir. 2024).

Analysis

Precedents Cited and Their Influence

• Rodriguez v. United States, 575 U.S. 348 (2015).
  Rodriguez anchors the “mission of the stop” framework: a traffic stop must remain tied to addressing the traffic infraction and attending to related safety concerns. The Tenth Circuit applied Rodriguez’s two pillars—mission and temporal prolongation—to assess whether the trooper’s actions departed from the stop’s tasks or added time without independent reasonable suspicion.
• United States v. Baker, 108 F.4th 1241 (10th Cir. 2024).
  Baker supplied both the standard of review and the operative three-part prolongation test: a stop becomes unreasonable when an officer (1) departs from the mission, (2) in a way that prolongs the stop, (3) without independent reasonable suspicion. Baker also reaffirmed that officers may act to ensure safety during a stop, including removing occupants from vehicles.
• United States v. Cone, 868 F.3d 1150 (10th Cir. 2017).
  Cited for the proposition that actions during a stop must be reasonably related to the stop’s mission.
• United States v. Mayville, 955 F.3d 825 (10th Cir. 2020).
  “Least intrusive means” is not the Fourth Amendment standard. This undermined Brown’s argument that the trooper should have shown him the fog lights from inside the car or taken a safer or more efficient approach.
• United States v. Malone, 10 F.4th 1120 (10th Cir. 2021).
  Reinforced that whether an officer’s request actually extended the stop is a factual finding reviewed for clear error—critical to upholding the district court’s finding that escorting Brown to the patrol car did not add time.
• South Dakota v. Opperman, 428 U.S. 364 (1976).
  The Supreme Court recognized the authority to remove from the streets vehicles that impede traffic or threaten public safety. Opperman supplied the decisive foundation for the hazard-based impoundment here.
• United States v. Venezia, 995 F.3d 1170 (10th Cir. 2021).
  Confirmed that the community-caretaking exception in the Tenth Circuit encompasses impoundments.
• United States v. Ulibarri, — F.4th —, 2025 WL 2371551 (10th Cir. 2025).
  Clarified that vehicle impoundment is a seizure generally requiring a warrant unless justified by community caretaking; imposed a governmental burden to show a reasonable, non-pretextual justification; recognized that mixed motives do not invalidate caretaking impoundments; and explained in a footnote that the five-factor Sanders test is inapplicable where a vehicle impedes traffic or threatens safety.
• United States v. Trujillo, 993 F.3d 859 (10th Cir. 2021).
  Elaborated the breadth of “impeding traffic” and “public safety and convenience,” and rejected a pretext claim lacking factual foundation. Trujillo also supports the view that officers need not allow a driver to arrange late-night retrieval before impoundment when the vehicle threatens traffic flow or safety.
• United States v. Kendall, 14 F.4th 1116 (10th Cir. 2021).
  Described two distinct bases for searching vehicles in police custody: (1) inventory searches to protect property and guard against claims, and (2) community-caretaking searches to protect the public (e.g., securing a firearm from vandals).
• Nixon v. City & County of Denver, 784 F.3d 1364 (10th Cir. 2015); Adler v. Wal-Mart Stores, Inc., 144 F.3d 664 (10th Cir. 1998).
  Established that failure to challenge an independent, alternative ground for a ruling results in waiver on appeal—dispositive of Brown’s challenge to the vehicle search.

Legal Reasoning

1) Scope and duration of the stop

The panel addressed two claimed prolongations. First, asking Brown to exit the car to view his fog lights was integral to the stop’s mission: the infraction was improper fog-light use, and Brown professed confusion about their location. Under Mayville, officers need not choose the least intrusive or most efficient method. The action’s reasonableness is judged by what the trooper actually did, not hypothetical alternatives. See Baker, 108 F.4th at 1250.

Second, escorting Brown to the patrol car so the trooper could write a warning neither departed from the stop’s mission nor extended the stop. The district court found as a fact that this did not add time, and Brown identified no record evidence to render that finding clearly erroneous. Independently, even if time had been added, Rodriguez recognizes that attending to officer safety is part of the mission, and Baker acknowledges officers can routinely remove occupants to ensure safety. The panel expressly stated this safety principle “controls” the escort request.

2) Impoundment as a community-caretaking seizure

The court reaffirmed that vehicle impoundment is a seizure ordinarily requiring a warrant, but one that falls within the community-caretaking exception when justified by public safety. See Ulibarri; Venezia. Opperman’s central proposition—that police may remove vehicles impeding traffic or threatening public safety or convenience—“resolves” the impoundment question here.

The key facts: the car was parked “just inches” from the shoulder line of a heavily trafficked interstate after midnight; stepping out of the car put Brown into the right-hand lane. The panel stressed the breadth of “impeding traffic” and “public safety,” citing Trujillo, and endorsed the district court’s common-sense conclusion that a vehicle in that position could cause drivers in the right lane to slow or change lanes, risking collisions.

On pretext, the panel found no factual foundation for the assertion that the impoundment was a ruse to search for evidence. Even had the officer harbored investigatory interest, Ulibarri and Trujillo tolerate mixed motives where a reasonable caretaking justification exists; only a purely investigatory purpose would present a constitutional problem.

Finally, the panel clarified the role of the five-factor test from United States v. Sanders, 796 F.3d 1241 (10th Cir. 2015). That framework applies when a vehicle neither impedes traffic nor threatens safety. It is inapplicable where, as here, a hazard exists. See Ulibarri, 2025 WL 2371551 at *5 n.4. Thus, arguments about alternative arrangements (e.g., having a relative retrieve the car) did not control the analysis; the court further noted that Trujillo does not require officers to facilitate late-night retrieval in hazardous circumstances.

3) Search of the impounded vehicle

The government offered two justifications below: an inventory search and a community-caretaking search to protect the public from a firearm in the car. The district court upheld the latter, finding a reasonable belief a gun was present—a belief supported by the trooper’s observation of a large knife, what appeared to be a holster clip on Brown’s waistband, and the dramatic circumstances of the stop (including Brown’s flight and return across the interstate).

On appeal, Brown challenged only the inventory-search rationale, ignoring the caretaking basis. Under Nixon and Adler, that omission constituted waiver of any challenge to the caretaking ruling. The panel therefore affirmed the search without reaching the inventory issue. Kendall confirms that a caretaking search of an impounded vehicle to secure a weapon from potential vandals is a recognized and distinct doctrine in the Tenth Circuit.

Impact and Implications

• Operational clarity for traffic stops: The opinion reinforces that officers may:
  • Ask a driver to exit to address the reason for the stop (here, to identify fog lights), and
  • Escort the driver to a patrol car to complete stop-related tasks, when tied to safety,
  without violating Rodriguez—especially where the record supports no temporal extension. Defendants challenging prolongation should marshal concrete record evidence that time was added and that the action lacked a safety nexus.
• Hazard-based impoundments streamlined: Where a vehicle impedes traffic or threatens public safety, officers need not satisfy the Sanders factors. This sharpened distinction, rooted in Opperman and clarified in Ulibarri, will likely reduce litigation over alternatives in clear hazard scenarios (e.g., vehicles on narrow shoulders, near travel lanes, or in high-speed environments at night).
• Mixed motives tolerated; pretext requires proof: The opinion underscores that mixed caretaking and investigatory motives do not invalidate an impoundment; suppression requires evidence that the sole purpose was investigatory. Mere assertions of pretext, without record support, will not suffice.
• Caretaking searches remain distinct from inventory searches: Kendall’s recognition of a public-safety search to secure firearms or contraband in an impounded vehicle provides an independent path for upholding searches even where inventory protocols might be contested. Defense counsel should be prepared to address both theories.
• Appellate practice lesson—preserve every independent ground: Brown’s failure to challenge the caretaking-search rationale was outcome-determinative. When a district court offers multiple, independent grounds for denying suppression, appellants must attack each one or risk waiver.
• Persuasive authority within the Tenth Circuit: Although unpublished and non-binding, the decision is consistent with, and builds upon, recent published circuit law, particularly Ulibarri, Kendall, Trujillo, and Baker. Expect it to be cited for its clear articulation of hazard-based impoundment and safety-justified escorts to patrol cars.

Complex Concepts Simplified

• “Mission of the stop” (Rodriguez): During a traffic stop, officers can do what’s reasonably necessary to address the traffic violation and ensure safety—request license/registration, run warrants, explain the violation, issue a citation or warning, and take basic safety measures. Unrelated criminal investigation that adds time without reasonable suspicion is an unlawful prolongation.
• Prolongation test (Baker): A stop is unlawfully prolonged when an officer (1) departs from the mission, (2) in a way that adds time, (3) without independent reasonable suspicion. All three are required; if any is missing (e.g., there’s no added time), the claim fails.
• Community-caretaking (vehicles): Distinct from criminal investigation, this doctrine lets police take reasonable steps to protect the public and property—like impounding a car that is a traffic hazard or searching an impounded car to secure a firearm from potential vandals.
• Inventory search vs. caretaking search:
  • Inventory search: A standardized, non-investigatory cataloging of items in an impounded vehicle, meant to protect the owner’s property and the police from claims or danger.
  • Caretaking search: A focused search to address an immediate safety problem, such as securing a weapon, independent of inventory protocols.
• Sanders factors: A five-factor test used in the Tenth Circuit to evaluate impoundments when no hazard exists. Brown confirms these factors do not apply when the vehicle impedes traffic or threatens safety.
• Pretext vs. mixed motive: A pretextual impoundment occurs when the sole purpose is to investigate crime, not to protect safety. Mixed motives (some investigatory interest plus genuine safety reasons) are permitted. The government must show a reasonable, non-pretextual caretaking justification; the defense must produce evidence of purely investigatory purpose to prevail.
• Standards of review: Appellate courts defer to the district court’s factual findings unless clearly erroneous but review the ultimate constitutional reasonableness de novo. Factual disputes about whether actions added time often decide prolongation claims.
• What counts as “impeding traffic” or a “safety threat”: It’s broader than physically blocking a lane. A vehicle close to a live lane on a high-speed interstate at night can cause other drivers to brake or change lanes and increases collision risk—sufficient to justify impoundment.
• Waiver on appeal: If the trial court gives multiple reasons for its decision, an appellant must challenge each one. If an independent ground goes unchallenged, the appellate court will typically affirm on that basis without reaching others.

Conclusion

United States v. Brown distills and applies core Fourth Amendment principles in three practical settings: conduct during a traffic stop, hazard-based impoundment, and the search of an impounded vehicle. The panel held that escorting a driver to a patrol car for a warning is either time-neutral or independently justified by officer safety; that a vehicle posing a traffic hazard may be impounded under the community-caretaking exception without resort to the Sanders factors; and that a caretaking search to secure a suspected firearm from an impounded car is valid—particularly where the appellant fails to challenge that ground on appeal.

While not binding precedent, Brown closely tracks and reinforces recent Tenth Circuit law, especially Ulibarri, Kendall, Trujillo, and Baker. Its most salient takeaways are:

• The mission-and-safety framework of Rodriguez allows reasonable safety steps, including relocating the driver, without constituting unlawful prolongation absent added time.
• Opperman’s hazard principle remains robust: when a vehicle threatens the efficient and safe movement of traffic, impoundment is justified; Sanders is inapplicable.
• Community-caretaking searches of impounded vehicles to secure weapons are distinct from inventory searches and can independently sustain a search.
• Appellate waiver rules can be outcome determinative; every independent ground must be challenged.

Collectively, these principles provide a clear, safety-centered roadmap for officers in the field and a precise analytic framework for courts and counsel assessing traffic-stop extensions, impoundments, and vehicle searches in the Tenth Circuit.