United States v. Lopez-Moreno
420 F.3d 420 (5th Cir. 2005)
Holding
A traffic stop is justified at its inception when an officer has an objectively reasonable suspicion that a traffic violation has occurred or is about to occur; witnessing a traffic violation—such as non-functioning brake lights—provides sufficient reasonable suspicion.
What This Case Is About
United States v. Lopez-Moreno is a landmark Fifth Circuit decision defining when a traffic stop is legally justified under the Fourth Amendment. While it is a federal criminal case involving transportation of undocumented aliens, Lopez-Moreno is one of the most frequently cited cases in § 1983 litigation because it establishes the foundational test for the legality of traffic stops: “For a traffic stop to be justified at its inception, an officer must have an objectively reasonable suspicion that some sort of illegal activity, such as a traffic violation, occurred, or is about to occur, before stopping the vehicle.”
The Facts
On the morning of August 21, 2003, Officer Earlton John Parker of the Greenwood Police Department in Greenwood, Louisiana, was on routine traffic patrol at approximately 2:36 a.m. He pulled over a white van because neither of its side brake lights was functioning—only the center window brake light was operating. Officer Parker believed the non-functioning brake lights violated Louisiana Revised Statute § 32:306A, which required all motor vehicles registered and operating in Louisiana to have at least two functioning brake lights.
Upon stopping the van, the officer discovered the driver, Eleuterio Lopez-Moreno, was transporting undocumented aliens. Lopez-Moreno was subsequently convicted of transporting undocumented aliens in furtherance of their illegal presence in the United States.
On appeal, Lopez-Moreno challenged the legality of the traffic stop, arguing that the officer lacked reasonable suspicion or probable cause to stop his vehicle. He also challenged the admission of certain documentary evidence and the sufficiency of the evidence supporting his conviction.
What the Court Decided
The Fifth Circuit affirmed the conviction and the denial of the motion to suppress. The court articulated the standard that has become the touchstone for traffic stop analysis in the Fifth Circuit:
“For a traffic stop to be justified at its inception, an officer must have an objectively reasonable suspicion that some sort of illegal activity, such as a traffic violation, occurred, or is about to occur, before stopping the vehicle.”
The court found that Officer Parker’s observation of the non-functioning brake lights gave him objectively reasonable suspicion that a traffic violation had occurred. The court reviewed the stop de novo and concluded that the officer had a legitimate basis for the traffic stop regardless of any subjective motivations.
The court also addressed the standard of review for probable cause determinations, noting that probable cause is reviewed de novo on appeal—a standard frequently applied in § 1983 cases.
Why This Case Matters for Your § 1983 Case
This is the controlling standard for traffic stops in the Fifth Circuit. If your § 1983 case arises from a traffic stop, Lopez-Moreno provides the test courts will apply: did the officer have an objectively reasonable suspicion that a traffic violation occurred or was about to occur?
Any observed traffic violation justifies a stop. Under this standard, even minor traffic infractions—a broken brake light, failure to signal, slightly exceeding the speed limit—give officers legal authority to stop a vehicle. This makes challenging the initial stop extremely difficult in most cases.
Objective standard, not subjective. The officer’s actual motivation for the stop is irrelevant. Even if the officer stopped the vehicle to investigate something else entirely, the stop is lawful if an objective traffic violation existed. This principle follows Whren v. United States.
De novo review of probable cause helps plaintiffs. The court’s holding that probable cause determinations are reviewed de novo means appellate courts take a fresh look at the evidence rather than deferring to the trial court. This gives § 1983 plaintiffs a meaningful opportunity to challenge probable cause findings on appeal.
Key Takeaway
Lopez-Moreno establishes the bright-line rule in the Fifth Circuit: if an officer observes any traffic violation, the resulting stop is lawful under the Fourth Amendment regardless of the officer’s subjective motivations. For § 1983 plaintiffs, this means that challenging the legality of a traffic stop requires showing that no objective basis for the stop existed—a high bar when virtually any minor traffic infraction suffices.