Evidence in New Jersey DWI Cases, Part 4: Field Sobriety Testing

In cases involving alleged driving while intoxicated (DWI) in New Jersey, prosecutors must prove all of the elements of the offense beyond a reasonable doubt. The New Jersey DWI statute states that a person commits an offense when they operate a vehicle “while under the influence” of drugs or alcohol. Prosecutors can prove this through testimony, such as by having the arresting officer testify about their observations of the defendant’s appearance or behavior, or through the defendant’s performance on field sobriety tests (FSTs). New Jersey evidence rules govern the ways prosecutors may introduce evidence of defendants’ performance on these tests at trial.

Accepted Field Sobriety TestsThe National Highway Traffic Safety Administration (NHTSA) has created standard procedures for three FSTs. New Jersey courts accept the use of two of the three tests in DWI investigations: the “One Leg Stand” and the “Walk and Turn”. HGN has not been held relaible to measure or check for intoxication, since there are 40 or more other causes of nystagmus in addition to intoxication.

– The “walk and turn” test involves taking nine heel-to-toe steps along a straight line, and then turning and taking nine heel-to-toe steps along the same line, back to the starting point. Officers look for whether the person maintains their balance, stays on the line, and maintains heel-to-toe contact.
– The “one-leg stand” test involves standing, feet together and arms at the side, lifting one leg about six inches off the ground, and counting aloud until told to stop. Officers look for swaying or hopping, moving one’s arms to maintain balance, or dropping the foot before being told to do so.
– The “horizontal gaze nystagmus” test involves focusing the eyes on a point, usually a pen or other object held by the officer, and following it with the eyes as the officer moves it from side to side. Officers look for whether the person can smoothly follow the object with both eyes, or if there are deviations or abrupt eye movements known as “nystagmus.”

Methods of Offering Evidence of Field Sobriety Test Performance

Poor performance on one or more FSTs can serve as circumstantial evidence of legal impairment. Prosecutors have two main methods of introducing evidence of a defendant’s performance on FSTs: eyewitness testimony from the officer who conducted the tests, and video footage of the tests. This evidence is usually not enough, by itself, to prove impairment, but it can supplement other evidence, like an officer’s testimony about the defendant’s behavior or the odor of alcohol.

Challenges to Field Sobriety Test Evidence

Once the case has proceeded to trial, the defendant cannot raise a general objection to testimony by the officer who conducted the FSTs, but they can cross-examine the officer to challenge specific statements or assertions. They may also be able to raise challenges to the manner in which the officer conducted the tests. If the officer deviated from the NHTSA guidelines, for example, the defendant could raise doubt about the results. The defendant can also dispute the state’s interpretation of video evidence, especially if it does not provide a clear image.

When the defendant presents their own case after the prosecution rests, they may be able to introduce evidence providing an alternative explanation for allegedly poor performance on a field sobriety test. Nystagmus, for example, can result from a variety of medical conditions besides intoxication. Injuries and other conditions could explain mistakes on the other two tests.

If you have been charged with DWI in New Jersey, DWI attorney Evan Levow can guide you through the court process and advocate for your rights. You can contact us today online or at (877) 593-1717 to schedule a free and confidential consultation with a member of our experienced and knowledgeable team.

More Blog Posts:

What Statements by a New Jersey DWI Defendant Are, and Are Not, Admissible in Court? New Jersey DWI Attorney Blog, October 17, 2017

New Jersey DWI Defendant Challenges Alcotest Results and Officer’s Observations as Evidence at Trial, New Jersey DWI Attorney Blog, March 6, 2017

Dashcam Videos from New Jersey Police Vehicles Are Public Record, According to Appellate Division Ruling, New Jersey DWI Attorney Blog, July 20, 2016