If you’re pulled over in New Jersey and an officer suspects you’ve been drinking, you’ll probably be asked to step out of the car and perform a series of roadside exercises — walking a straight line, standing on one leg, following a pen with your eyes. Most drivers assume they have to comply. They don’t. New Jersey law does not require you to take field sobriety tests, and declining them carries no separate penalty. But there’s an important catch: one test — the breath test at the station — is treated completely differently, and confusing the two can cost you your license.
What Are Field Sobriety Tests?
Field sobriety tests (FSTs) are physical and cognitive exercises police use at the roadside to build probable cause for a DWI arrest. The three standardized tests recognized by the National Highway Traffic Safety Administration are:
- Horizontal gaze nystagmus (HGN): the officer watches your eyes as you track a pen or light, looking for involuntary jerking.
- Walk-and-turn: nine heel-to-toe steps along a line, a pivot, and nine steps back.
- One-leg stand: standing on one foot while counting aloud, usually for about 30 seconds.
Officers sometimes add non-standardized exercises — reciting the alphabet, counting backward, touching a finger to your nose. These have even less scientific support than the standardized three.
Are You Legally Required to Take Them?
No. New Jersey’s implied consent law applies to breath samples, not roadside physical tests. There is no fine, no license consequence, and no separate charge for politely declining to perform field sobriety tests.
That said, declining is not a magic shield. An officer who already has other evidence — the smell of alcohol, erratic driving, slurred speech, an admission that you had “a couple of drinks” — can still arrest you based on those observations. If you do decline, do it calmly and respectfully. Arguing at the roadside never helps, and everything you say and do is likely being recorded.
The Breath Test Is a Different Story
Here is where drivers get into trouble. Under N.J.S.A. 39:4-50.2, every driver on New Jersey roads has already consented to provide a breath sample (the Alcotest) after a lawful DWI arrest. Refusing the breath test is a separate offense from DWI itself, with its own penalties. For a first refusal, those may include:
- A fine of $300–$500
- Loss of your license until an ignition interlock device is installed, with the interlock required for 9 to 15 months after restoration
- Mandatory participation in the Intoxicated Driver Resource Center program
- Insurance surcharges of $1,000 per year for three years
You can be convicted of refusal even if you’re never convicted of DWI — and you can be charged with both. If you’ve been charged with refusing the breath test, our page on DWI refusal in NJ explains how these cases are defended.
How Reliable Are Field Sobriety Tests?
Far less reliable than most people assume. Even under ideal conditions in controlled studies, the standardized tests misidentify a meaningful percentage of sober people as impaired. In the real world, conditions are rarely ideal. Performance can be affected by:
- Medical conditions, injuries, or inner-ear problems that affect balance
- Age, weight, and physical fitness
- Footwear, uneven pavement, gravel, or a sloped shoulder
- Weather, darkness, and passing headlights
- Simple nerves — being ordered through unfamiliar exercises by an armed officer on the side of a highway is stressful for anyone
Grading is also subjective. The officer decides, in the moment, whether you “failed.” An experienced defense attorney will scrutinize whether the tests were properly instructed and administered, whether the officer followed standardized procedures, and whether dashcam or bodycam footage actually matches what the police report claims.
What to Do If You Were Arrested After Field Sobriety Tests
- Write down everything you remember — where the tests happened, the surface and lighting, what instructions you were given, any medical issues that affected you.
- Don’t discuss the stop with anyone but your lawyer, and stay off social media.
- Act quickly. Video evidence can be overwritten, and early defense work matters in municipal court.
- Talk to a DWI defense attorney before your first court date. Field sobriety test evidence is often the weakest part of the State’s case, and challenging it can change the outcome. Learn more about how we defend these cases on our New Jersey DWI defense page.
A roadside test performed under stress, on a dark shoulder, graded by the arresting officer, should never be the thing that decides your future. If field sobriety tests played a role in your DWI arrest, have them examined by someone who knows exactly what to look for.
Jenna Casper Bloom is a criminal defense attorney based in Flemington, NJ. She defends drivers across Hunterdon, Somerset, Morris, Warren, and Mercer counties against DWI and refusal charges. Contact Casper Bloom Law at /contact/ for a free, confidential consultation.
