Challenging Field Sobriety Test Evidence in New Jersey DWI Cases

New Jersey allows the state to prove driving while intoxicated (DWI) by having police officers testify about a defendant’s behavior or appearance. They may ask a defendant to participate in field sobriety tests (FSTs), which can supposedly demonstrate impairment. Unlike breath testing, FSTs are not mandatory under New Jersey law. If you agree to perform FSTs during a traffic stop, and the police arrest you for DWI, you may be able to challenge the evidence based on a variety of factors. A DWI lawyer can advise you about which defenses might be available to you.

What Field Sobriety Tests May New Jersey Police Use?

Police in New Jersey have official approval for three FSTs. They may use other tests as well, but anything other than the officially approved tests does not have any scientific support behind it.

Officially Approved Tests

Three FSTs have at least some scientific support as ways to detect intoxication or impairment. Their reliability is still a matter of much dispute.
– One-Leg Stand (OLS): You must stand straight, with your arms at your side, and lift one leg about six inches off the ground for thirty seconds.
– Walk-and-Turn (WAT): You must walk heel-to-toe in a straight line for nine steps, counting each step out loud. You must then turn around and return to the starting point with nine more heel-to-toe steps.
– Horizontal gaze nystagmus (HGN): This is the most controversial of the three official tests. The officer will hold a pen or other object in front of your face. You must follow the object with your eyes, without moving your head. The officer is looking for involuntary eye movements that allegedly indicate impairment.

Other Tests

Police officers may ask you to complete other FSTs that will be of limited use as evidence in court. These might include:
– Extending your arms outward and touching your nose while bending only your elbows;
– Touching each finger on your hand to your thumb while counting out loud; or
– Counting or reciting the alphabet backward.

How Can I Challenge Field Sobriety Test Evidence?

You may be able to challenge the results of official FSTs on several grounds.

Instructions from the Officer

An officer must give you specific instructions for each test in a form provided by the government. Failure to follow the instructions can work against you, but failure to provide the instructions correctly could work in your favor.


The officer should ask if you have any injuries that could affect the tests. You cannot perform the tests if you have a foot, knee, leg, back, neck, or head injury or a condition that affects balance.

Weather Conditions

Rainy, snowy, or icy conditions can significantly affect your ability to perform FSTs.

Ground Conditions

Roadsides, where most FSTs occur, are less than ideal locations. They might feature broken pavement or other uneven surfaces.


Was the area well-lit enough to allow the officer to observe your performance accurately?

Clothing and Shoes

Were you wearing something that could interfere with the FSTs? Did the officer consider that?

Age and Weight

Anyone who is at least 65 years old or fifty or more pounds overweight should not perform the OLS or WAT tests.

DWI is a serious offense in New Jersey. Its impact on your life can be significant. You need an experienced DWI attorney who can prepare the best possible defense. Evan Levow has dedicated his law practice to DWI defense. Please contact us today online or at (877) 593-1717 to schedule a free and confidential consultation to discuss your case.

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