How New Jersey Police Use Field Sobriety Tests in DWI Investigations

Police in New Jersey have many ways to build a case for driving while intoxicated (DWI). They can establish probable cause for an arrest by instructing a suspect to perform field sobriety tests (FSTs). A “perfect” performance on FSTs is essentially impossible and is unlikely to help someone avoid arrest regardless. Defending against New Jersey DWI charges that include alleged failed FSTs means challenging whether police officers correctly administered the tests. A Pennsylvania town recently sought volunteers for an unusual form of police training. New Jersey police have not yet asked for volunteers to get drunk so officers can practice administering FSTs, but the outcome of the Pennsylvania training may change that.

State law allows prosecutors to make a case with evidence of impairment besides blood alcohol content (BAC). The DWI statute defines the offense, in part, as driving a motor vehicle “while under the influence” of alcohol or drugs. Eyewitness testimony from officers, including FST performance, is often the main evidence presented by the state.

The National Highway Traffic Safety Administration (NHTSA) has established a set of standardized FSTs that most states have adopted. The set of standardized FSTs consists of three tests:
1. One-Leg Stand: The suspect must raise one foot about six inches off the ground and hold it there.
2. Walk and Turn: The suspect must walk a straight line, keeping their heel to their toe with each step, for a total of nine steps. Then, they must turn 180 degrees and repeat the process until they return to the starting point.
3. Horizontal Gaze Nystagmus: The officer holds a pen or other object at a constant distance from the suspect’s face while moving it from side to side. The suspect must follow the object with their eyes without moving their head. The officer is looking for involuntary eye movement, known as nystagmus, supposedly associated with intoxication.

The New Jersey Appellate Division addressed a challenge to the constitutionality of FSTs under the Fourth Amendment in a 2011 decision. The court cited a 1996 decision by the U.S. Supreme Court, Whren v. United States, which held that a traffic stop is a “seizure” of one or more persons within the meaning of the Fourth Amendment. A stop is “reasonable,” the Supreme Court ruled, when “police have probable cause to believe that a traffic violation has occurred.”

The Supreme Court’s ruling implies that police can only investigate matters related to the initial suspected traffic violation, which might not be DWI. The New Jersey court, however, held that police can “broaden[] the inquiry” when circumstances “give rise to suspicions unrelated to the traffic offense.” If the police pull someone over for speeding, running a red light, or failing to use a turn signal, for example, they can expand the scope of their investigation if evidence other evidence leads them to reasonably suspect DWI. This might include the driver’s alleged appearance or behavior or the odor of alcohol.

FSTs, the Appellate Division and other courts have held, are a reasonable means of continuing a DWI investigation after a traffic stop. Part of a good defense against DWI charges involves thorough challenges to every step in the process from the decision to stop a defendant’s vehicle to the decision to arrest them.

If you have questions about a field sobriety test related to an alleged DWI charge in New Jersey, DWI attorney Evan Levow is available to discuss your rights and options. Please contact us at (877) 593-1717 or online today to schedule a free and confidential consultation with a member of our knowledgeable and experienced team.