Heien v. North Carolina: The Brake-Light Case That Changed Traffic Stops

Landmark case

Heien v. North Carolina (2014) is the U.S. Supreme Court case holding that a police officer’s objectively reasonable mistake about the law can still provide reasonable suspicion for a traffic stop. It began with one burned-out brake light on I-77 in Surry County, and it now shapes how every equipment-violation stop, including many DWI stops, is litigated in North Carolina and across the country.

What did Heien v. North Carolina decide?

Heien v. North Carolina decided that the Fourth Amendment tolerates reasonable mistakes of law, just as it tolerates reasonable mistakes of fact. If an officer stops a car because he reasonably, but wrongly, believes a traffic law was broken, the stop can still be constitutional.

Writing for the Court, Chief Justice Roberts reasoned that the Fourth Amendment demands reasonableness, not perfection. Officers already get leeway when they misjudge facts (for example, mistaking one person for another). The Court saw no principled reason to treat a reasonable misreading of an unclear statute differently. But the mistake must be objectively reasonable: courts do not ask what this officer believed or was trained to believe, and an officer gains nothing from “sloppy study of the laws he is duty-bound to enforce.”

Justice Kagan, joined by Justice Ginsburg, concurred to stress how narrow the rule is: the statute must be genuinely ambiguous, so that overturning the officer’s reading takes hard interpretive work. Both sides told the Court such cases would be exceedingly rare. Justice Sotomayor dissented, arguing that the law should be what it is, and that a mistake of law, however reasonable, should not justify seizing someone.

The stop: one brake light on I-77 near Dobson

On April 29, 2009, a Surry County Sheriff’s sergeant was patrolling Interstate 77 near Dobson when he noticed a Ford Escort whose left brake light worked but whose right brake light did not. He stopped the car for the faulty light.

While preparing a warning ticket, the sergeant became suspicious: the driver seemed nervous, the car’s owner, Nicholas Heien, was lying down in the back seat, and the two men gave inconsistent answers about where they were going. Heien consented to a search, and officers found cocaine in a duffel bag. He was charged with attempted trafficking in cocaine and moved to suppress, arguing the stop itself was illegal because North Carolina law did not require two working brake lights.

The statute: “a stop lamp” versus “all originally equipped rear lamps”

The case turned on how to read North Carolina’s vehicle-lighting statute as it stood in 2009. One subsection required a car to be equipped with “a stop lamp” on the rear; another required “all originally equipped rear lamps” to be in good working order.

The North Carolina Court of Appeals read “a stop lamp” literally: one working brake light was enough, so Heien’s car was legal and the stop was not justified. The Supreme Court of North Carolina did not decide that question. It assumed the car was legal, but held that the sergeant’s reading was reasonable, especially because the statute also said the stop lamp “may be incorporated into a unit with one or more other rear lamps,” which suggested a brake light might count as a “rear lamp” that had to work. No North Carolina appellate court had interpreted the provision before.

So the specific question in Heien is now settled by statute: in North Carolina, as of November 2026, a car built after 1970 with one working brake light and one dead one is in violation, and an officer may stop it. Heien’s lasting importance is the broader rule about mistakes of law.

How the case moved through the courts

Heien’s suppression motion produced five appellate decisions in three courts over three years before the U.S. Supreme Court had the final word.

1. April 29, 2009Surry County deputy stops the Ford Escort on I-77 near Dobson for a broken right brake light; consent search finds cocaine.
2. Trial courtMotion to suppress denied: the faulty brake light gave reasonable suspicion.
3. 2011N.C. Court of Appeals reverses (214 N.C. App. 515): “a stop lamp” means one working light was enough, so the stop was not justified.
4. 2012Supreme Court of North Carolina reverses (366 N.C. 271): even assuming no violation, the officer’s mistake of law was reasonable.
5. 2013On remand, the Court of Appeals affirms the denial of suppression; the Supreme Court of North Carolina affirms (367 N.C. 163).
6. Dec. 15, 2014U.S. Supreme Court affirms, 8–1 (574 U.S. 54).
7. Oct. 1, 2015S.L. 2015-31 takes effect, requiring stop lamps on each side of the rear for post-1970 vehicles.

What counts as a “reasonable” mistake of law?

A mistake of law is reasonable only when the statute is genuinely ambiguous and no controlling court decision has resolved it. A mistake about a clear statute, or about settled law, is not reasonable, and a stop based on it is unconstitutional.

North Carolina’s leading example on the other side of the line is State v. Eldridge (2016). An officer stopped a Tennessee-registered vehicle because it had no driver’s-side exterior mirror, believing North Carolina law required one; his supervisor agreed. But the mirror statute, G.S. 20-126(b), applies by its terms only to vehicles “registered in this State.” Because the statute was unambiguous, the Court of Appeals held the mistake was not objectively reasonable under Heien, the stop was unconstitutional, and the motion to suppress should have been granted.

Why Heien matters in North Carolina DWI cases

Many DWI investigations start with an equipment or minor traffic stop, not with weaving or a crash. Heien means that if the officer misread an ambiguous traffic law, the DWI evidence that followed may still come in. If the law was clear, Heien does not save the stop.

Under Whren v. United States (1996), an officer’s motive does not matter if a traffic violation objectively justified the stop. Put Whren and Heien together, and the key question in an equipment-stop DWI is precise: did the specific statute the officer relied on actually prohibit what the officer saw, and if not, was the officer’s contrary reading objectively reasonable? That requires reading the statute as it existed on the date of the stop, because North Carolina amends Chapter 20 often.

Typical equipment and technical stops that raise Heien issues include lighting, mirrors, window tint, license-plate display and registration questions, especially for out-of-state vehicles visiting Lake Norman or passing through on I-77 and I-85. Our guide on out-of-state drivers charged with DWI at Lake Norman covers related issues, and our overview of how to review DWI evidence explains how stop issues are investigated.

Heien, the North Carolina Constitution and State v. Rogers (2025)

For decades, North Carolina defendants could argue that the state constitution offered more protection than the Fourth Amendment because the Supreme Court of North Carolina had refused to adopt a “good faith” exception. That changed in October 2025.

In State v. Carter (1988), the Supreme Court of North Carolina held that evidence obtained in violation of Article I, Section 20 of the state constitution must be excluded, with no good-faith exception. On October 17, 2025, in State v. Rogers, the court expressly overruled Carter and held that any exclusionary rule arising from Article I, Section 20 is subject to a good-faith exception, as under the Fourth Amendment, where officers reasonably relied on judicial authorization later found invalid. According to the UNC School of Government’s analysis, Rogers did not decide whether the state constitution requires an exclusionary rule at all.

Two points keep this straight. First, Heien and the good-faith exception are different doctrines: Heien asks whether there was a constitutional violation at all (was there reasonable suspicion?), while good faith asks whether evidence should be excluded after a violation. Second, North Carolina’s statutory suppression rule, G.S. 15A-974, has had its own good-faith provision since 2011 for substantial violations of Chapter 15A. After Rogers, arguments that the North Carolina Constitution gives broader protection against an unreasonable stop must be made carefully and with current research.

Key cases on mistakes of law and traffic stops

These are the decisions that define how Heien works in North Carolina courts today.

How a defense lawyer analyzes a “mistake of law” stop

Challenging an equipment or technical stop after Heien is a statutory-reading exercise backed by evidence. The steps below are the usual path.

1. Pin down the stated reason

   From the citation, the DWI report, CAD notes and the officer’s testimony. “Equipment violation” is not specific enough; identify the statute and subsection.

2. Read the statute as of the stop date

   Check the version in effect that day, including session-law changes such as S.L. 2015-31.

3. Compare the statute to the facts

   Use video and photos of the vehicle. Did the light, mirror, tint or plate actually violate the statute’s words?

4. If not, ask whether the mistake was reasonable

   Is the statute genuinely ambiguous? Has any appellate court interpreted it? Is the vehicle out-of-state, as in Eldridge?

5. Look for an independent basis

   Even if the stated reason fails, the State may argue another lawful reason existed (speeding, weaving). The video often settles that.

6. File before trial

   In district court DWI cases, suppression motions generally must be filed before trial under G.S. 20-38.6.

For other stop issues, see our notes on State v. Barnard (green-light delay), State v. Johnson (fishtailing in snow) and State v. Bartlett (written findings on suppression).

Quiz: reasonable mistake or unlawful stop?

Test how well you understand the Heien rule. These questions are based on the decisions discussed above.

After Heien, the question isn’t just “what did the officer think the law was?” It’s “what does the statute actually say, and could a reasonable officer have read it the other way?”Adkins & Purkey

Heien v. North Carolina FAQ

Related guides

General North Carolina legal information as of November 2026, not legal advice for any specific case. Reading this article does not create an attorney-client relationship. Attorney advertising.