When a driver is stopped under suspicion of Driving While Intoxicated (DWI) in New Jersey, law enforcement officers typically rely on field sobriety tests (FSTs) to determine impairment. While these tests are frequently used as critical evidence in court, many people are unaware of how they work, how accurate they really are, and—most importantly—how their results can be challenged effectively in court.
In this article, we’ll examine the most commonly administered field sobriety tests in New Jersey, assess their reliability, and explore how an experienced DWI attorney can successfully challenge their validity in your defense.
Common Types of Field Sobriety Tests in New Jersey
In New Jersey, law enforcement officers typically use three standardized field sobriety tests, recommended by the National Highway Traffic Safety Administration (NHTSA):
1. Horizontal Gaze Nystagmus (HGN) Test
The HGN test measures involuntary eye movements (nystagmus) as a suspect’s eyes follow a moving object, usually a pen or flashlight. Officers look for three indicators of impairment:
- Lack of smooth pursuit.
- Distinct eye jerking at maximum deviation.
- Eye jerking before the eyes reach a 45-degree angle.
While the HGN test is widely considered the most scientifically reliable of the three standardized tests, it is often challenged due to improper administration or because certain medical conditions can mimic signs of impairment.
Important Note: New Jersey courts have historically been skeptical of the HGN test, and its results are generally not admissible in court without expert testimony.
2. Walk-and-Turn Test
The walk-and-turn test involves the driver walking heel-to-toe in a straight line, turning around after nine steps, and returning in the same manner. Officers watch closely for signs of impairment, including:
- Difficulty balancing.
- Starting the test too early.
- Failing to walk heel-to-toe accurately.
- Using arms for balance.
- Taking the wrong number of steps.
This test is meant to measure the driver’s ability to follow instructions and maintain physical coordination. However, external factors like uneven road surfaces, weather conditions, or footwear can significantly impact test performance.
3. One-Leg Stand Test
In this test, drivers must stand on one foot while counting aloud for about 30 seconds. Officers look for impairment indicators such as:
- Swaying or losing balance.
- Using arms to maintain balance.
- Hopping to maintain balance.
- Putting the raised foot down early.
Similar to the walk-and-turn test, physical conditions, age, fatigue, injuries, and even nervousness can influence performance, often leading to unreliable results.
Reliability and Limitations of Field Sobriety Tests
Although standardized field sobriety tests are commonly used, their reliability has been frequently questioned by legal experts. According to NHTSA research, the overall accuracy rates for detecting impairment (when tests are performed perfectly under ideal conditions) are as follows:
- HGN test: 77% accuracy.
- Walk-and-turn test: 68% accuracy.
- One-leg stand test: 65% accuracy.
These accuracy rates clearly indicate that a substantial margin for error exists, even under perfect circumstances. In real-world situations, factors such as uneven pavement, adverse weather, health conditions, age, medications, and anxiety can lead to false positives. Officers might incorrectly interpret these factors as signs of intoxication.
Challenging Field Sobriety Test Results in New Jersey Courts
If you’ve been arrested for a DWI in New Jersey based on the results of field sobriety tests, a knowledgeable DWI attorney can challenge this evidence effectively. Common defenses include:
1. Officer’s Training and Administration Errors
Officers must receive proper training and strictly adhere to NHTSA guidelines when administering sobriety tests. Failure to follow these protocols can invalidate results. An experienced attorney can review dashcam footage, police reports, and officer training records to pinpoint procedural errors.
2. Medical Conditions
Various medical conditions—including inner ear disorders, injuries, neurological issues, or vision problems—can compromise your performance on field sobriety tests. A defense attorney can introduce medical records or expert testimony to show that the results were impacted by health conditions rather than alcohol impairment.
3. Environmental Factors
External conditions, such as weather, poor lighting, uneven terrain, heavy traffic noise, or unsuitable footwear, can negatively affect your ability to perform tests successfully. Your attorney can highlight these conditions to cast doubt on the accuracy of the test results.
4. Subjective Officer Judgment
FST results rely significantly on the subjective observations of police officers. Defense attorneys can question the objectivity and accuracy of the officer’s perceptions, especially in borderline cases where impairment indicators were minimal or ambiguous.
Protecting Your Rights After a DWI Arrest
Field sobriety tests can significantly impact the outcome of a DWI case, but they’re far from foolproof. If you’ve been charged with DWI based on these tests, hiring an experienced New Jersey DWI defense attorney is crucial. Your lawyer can scrutinize every aspect of your arrest and aggressively challenge field sobriety test results, potentially leading to reduced charges, dismissal of your case, or an acquittal.
Attorney Anthony N. Palumbo has more than 35 years of experience defending clients in New Jersey DWI cases. Contact our firm today at 908-987-2937 for a free consultation to discuss your case, understand your options, and start building a strong defense.
When it comes to your freedom and reputation, you deserve dedicated, experienced representation.
