Supreme Court Rules that Traffic Stop Was Lawful, Despite Police Officer’s Misunderstanding of Traffic Law

The U.S. Supreme Court issued a ruling in December 2014 that could have a significant effect on DWI cases in New Jersey. The case involves two fundamental principles of the American criminal justice system. First, law enforcement officers must have reasonable suspicion of a criminal or traffic offense in order to make a traffic stop. Second, it is not a defense to prosecution for a person to claim that he or she did not know something was illegal. What happens, however, when a police officer makes a mistake of law? In Heien v. North Carolina, a defendant argued that a traffic stop that resulted in drug charges was unreasonable because the officer incorrectly thought having only one working brake light was a traffic violation. The court held that the officer did not violate the defendant’s rights, despite not knowing the law, since the mistake was “reasonable.”

An officer pulled the defendant’s vehicle over in April 29, 2009 at about 8:00 a.m. He testified that he saw the vehicle pass on the highway and thought the driver looked “very stiff and nervous.” After following the vehicle for several miles, he noticed that it had only one working brake light. He pulled the vehicle over, believing this to be a traffic violation. The defendant, who owned the vehicle, consented to a search, and the officer found drugs.

The defendant pleaded guilty to drug charges after the trial court denied his motion to suppress the results of the search, reserving the right to appeal. A state appellate court reversed the conviction, finding that the traffic stop was unreasonable because the driver had not broken any traffic laws. The North Carolina Supreme Court reversed that ruling, and the U.S. Supreme Court affirmed the conviction.

The defense of many DWI cases involves, at least in part, challenging the reasonableness of a traffic stop. Chief Justice Roberts, writing for the majority, noted that reasonable mistakes of fact that lead to traffic stops generally do not violate the Fourth Amendment, and therefore neither do reasonable mistakes of law by police officers. The central issue for the court seemed to be that the officer had a reasonable suspicion of an offense based on his reasonable belief regarding what state law prohibited. Another way of looking at the issue is that, however reasonable the officer’s suspicions or beliefs might have been, he did not know the traffic laws he was charged with enforcing.

Justice Sotomayor, the lone dissenter, wrote that determining the reasonableness of a traffic stop should involve “evaluating an officer’s understanding of the facts against the actual state of the law.” She noted that the legal system sees police officers as having “expertise” to assess the facts of a situation, but that “the law is not probabilistic in the same way that factual determinations are.” Under the Heien ruling, it seems as though the most meaningful check on a police officer’s ability to make traffic stops could be his or her willingness, or unwillingness, to admit ignorance of the law in court.

A New Jersey DWI arrest can seriously affect your life, even without a charge or conviction. A knowledgeable and experienced DWI attorney can protect your rights and prepare the best possible defense for your case. We have dedicated 100% of our law practice at Levow & Associates to the defense of DWI charges. Contact us online or at (877) 975-3399 to schedule a free and confidential consultation to see how we may assist you.

More Blog Posts:

Court Ruling May Make Footage of Traffic Stops Available Earlier in New Jersey DWI Cases, New Jersey DWI Attorney Blog, November 28, 2014

Driver Successfully Fights DWI by Citing First Amendment, New Jersey DWI Attorney Blog, October 30, 2014

New Jersey DWI Car Stop Based on a “Tip Call”, New Jersey DWI Attorney Blog, May 12, 2011

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