Traffic Stops, Field Sobriety Tests & Missteps That Can Help Your Defense

Traffic stops are one of the most common ways criminal investigations begin in New York. While many stops end with a warning or citation, others escalate into DWI arrests or other criminal charges based on an officer’s observations and the results of field sobriety tests. What many drivers do not realize is that these investigations are far from flawless. Mistakes by law enforcement during a stop or roadside investigation can create opportunities to challenge the prosecution’s case.

At Dupée & Monroe, P.C., our Goshen DWI/DWAI defense lawyers represent drivers throughout Orange County and the Hudson Valley who are facing DWI and related criminal charges. Understanding how traffic stops and field sobriety testing work—and where errors commonly occur—can help individuals protect their rights and better understand their defense options.

How Traffic Stops Begin

Under both the United States Constitution and New York law, police officers generally need reasonable suspicion that a traffic violation or criminal offense has occurred before initiating a stop. Common reasons for traffic stops include:

• Speeding
• Failure to maintain a lane
• Broken taillights or equipment violations
• Rolling through stop signs
• Allegations of erratic driving

In DWI investigations, officers often claim they observed behaviors such as weaving, drifting, delayed braking, or inconsistent speeds. However, many innocent explanations can exist for these observations, including fatigue, distraction, poor road conditions, or weather. The legality of the initial stop is extremely important. If the officer lacked sufficient legal justification, evidence obtained afterward may potentially be challenged in court.

What Officers Look for During a DWI Investigation

Once the stop occurs, officers begin gathering additional observations that may support a DWI arrest. They frequently document factors such as:

• Odor of alcohol
• Bloodshot or watery eyes
• Slurred speech
• Confusion or delayed responses
• Open containers in the vehicle

These observations are subjective and often open to interpretation. For example, bloodshot eyes can result from allergies, fatigue, or contact lenses. Nervousness during a traffic stop is also extremely common and does not necessarily indicate intoxication. Officers may then ask the driver to step out of the vehicle and perform field sobriety tests.

How Field Sobriety Tests Work

Field sobriety tests are roadside exercises intended to help officers assess whether a driver may be impaired. The National Highway Traffic Safety Administration (NHTSA) recognizes three standardized field sobriety tests:

Horizontal Gaze Nystagmus (HGN)

This test involves tracking eye movement while the officer moves an object, such as a pen or flashlight, side to side. Officers look for involuntary jerking of the eyes that they associate with alcohol impairment.

Walk-and-Turn Test

The driver is instructed to take heel-to-toe steps along a straight line, turn, and return in the same manner. Officers look for “clues” such as stepping off the line, missing heel-to-toe contact, or losing balance.

One-Leg Stand Test

The driver must stand on one foot while counting aloud. Swaying, hopping, or putting the foot down may be interpreted as signs of impairment.

While these tests are commonly used, they are not foolproof and are highly dependent on proper administration and interpretation.

Common Problems With Field Sobriety Tests

Field sobriety testing is vulnerable to many errors and inaccuracies. Numerous factors unrelated to alcohol or drugs can affect performance.

Poor Testing Conditions

Many roadside environments are not suitable for balance-based testing. Uneven pavement, gravel, poor lighting, rain, snow, traffic noise, or passing vehicles can interfere with performance.

Medical Conditions and Physical Limitations

Back problems, knee injuries, neurological conditions, vertigo, obesity, age, and certain medications may impact a person’s ability to complete the exercises successfully.

Anxiety and Nervousness

Even completely sober individuals may struggle during roadside tests because they are frightened, stressed, or intimidated by the situation.

Improper Instructions

Officers must administer standardized tests according to established guidelines. Incomplete or confusing instructions can compromise the reliability of the results.

Confirmation Bias

In many cases, officers begin forming conclusions before testing even starts. Once an officer suspects impairment, ordinary behavior may be interpreted in a way that supports arrest.

These weaknesses often become important issues during plea negotiations, suppression hearings, or trial.

Are Field Sobriety Tests Mandatory in New York?

Field sobriety tests are generally voluntary in New York. Drivers are not legally required to perform roadside coordination tests in most situations. However, refusing may still influence how the officer proceeds with the investigation. Chemical breath testing after arrest is a separate issue. New York’s implied consent law imposes consequences for refusing an official chemical test, including driver’s license suspension and civil penalties. Because the legal implications can be complicated, individuals should speak with an attorney as soon as possible after a DWI arrest.

Strategic Responses During a Traffic Stop

Drivers should remain calm and avoid escalating the encounter during any traffic stop. Certain actions can help protect both safety and legal rights. Provide required documents when requested, including license, registration, and insurance information. Avoid arguing with the officer at the roadside. Disputes about the legality of the stop or arrest can be addressed later through legal counsel. Be mindful that statements made during the stop may later appear in police reports or testimony. Casual comments about drinking, medication use, or fatigue can become evidence. Drivers also have the right to remain silent regarding potentially incriminating questions. Politely declining to answer investigatory questions is often advisable.

How Police Errors Can Strengthen a Defense

Not every DWI arrest results in a conviction. Errors made during the stop, investigation, or arrest process can create significant defense opportunities.
Examples may include:

• Lack of reasonable suspicion for the stop
• Improper administration of field sobriety tests
• Inaccurate police reports
• Failure to preserve body camera footage
• Constitutional violations during questioning or detention
• Problems with chemical test procedures or calibration

An experienced criminal defense attorney can examine police reports, video footage, testing records, and witness accounts to identify weaknesses in the prosecution’s case.

Why Early Legal Representation Matters

DWI and traffic-related criminal cases move quickly in New York. Important deadlines may apply to license suspension hearings, discovery requests, and suppression motions. Early legal intervention allows the defense to preserve evidence and begin building a strategy immediately.

Many people make the mistake of assuming that a roadside test or an arrest automatically means conviction. In reality, every stage of the investigation can be scrutinized for legal and factual issues. Even a first-time DWI conviction can carry serious penalties, including fines, license suspension, increased insurance costs, probation, ignition interlock requirements, and possible jail time. The consequences become even more severe for repeat offenses.

Frequently Asked Questions About Traffic Stops & Field Sobriety Tests

Can police pull me over just to see if I’ve been drinking?

No. Police need reasonable suspicion of a traffic violation or criminal activity before conducting a stop.

Are field sobriety tests accurate?

Field sobriety tests are subjective and can be affected by medical conditions, nervousness, weather, road conditions, and improper administration.

Do I have to take field sobriety tests in New York?

Roadside field sobriety tests are voluntary, although a refusal will carry immediate consequences in terms of license suspension, and the fact of your refusal can be used against you in court.

Can a DWI case be dismissed because of police mistakes?

Yes. Illegal stops, constitutional violations, improper testing procedures, or unreliable evidence can sometimes lead to suppression of evidence or dismissal of charges.

What should I say to the police during a traffic stop?

You must provide identification and required documents, but you also have the right to avoid answering potentially incriminating questions such as where you’ve been or how much you’ve had to drink.

Contact Dupée & Monroe, P.C. for Experienced DWI Defense in Orange County

A traffic stop can escalate quickly into a criminal investigation with serious consequences. However, roadside investigations and field sobriety tests are not infallible, and mistakes by law enforcement can play a critical role in your defense. At Dupée & Monroe, P.C., we represent drivers throughout Orange County and the Hudson Valley facing DWI and other criminal charges. We carefully examine every aspect of the stop, testing procedures, and arrest to identify weaknesses in the prosecution’s case and protect our clients’ rights.

If you were arrested after a traffic stop in New York, contact Dupée & Monroe, P.C., in Goshen today for a complimentary consultation and discuss your legal options.