What Counts as Probable Cause for a DWI Arrest in New York?

Being pulled over on suspicion of drunk driving can be one of the most stressful experiences a driver can face. What begins as a simple traffic stop can quickly escalate into a full DWI investigation, often leaving drivers confused about their rights and what evidence law enforcement is allowed to use. In New York, every DWI arrest must be supported by a specific legal standard known as probable cause. Knowing what qualifies as probable cause, and how it differs from reasonable suspicion is critical to determining whether a DWI arrest was lawful or not.

If you have been arrested for DWI in New York, you need an experienced attorney who can challenge the legality of the stop and the evidence gathered against you. Long Island DWI lawyer Jason Bassett of The Law Offices of Jason Bassett, P.C. has extensive experience defending clients accused of drunk driving and uncovering police errors that can make or break a case. To learn more about what counts as probable cause for a DWI arrest in New York, or to schedule a free consultation, call (631) 259-6060 today.

The Legal Foundations of a DWI Case in New York: Reasonable Suspicion and Probable Cause

A common misconception is that a police officer needs hard evidence of intoxication before stopping a driver. In reality, New York DWI cases rest on two distinct but related legal thresholds: reasonable suspicion and probable cause. Each serves a unique role in the sequence of a lawful arrest. The first justifies the traffic stop, and the second justifies the arrest. If law enforcement fails to meet either requirement at the appropriate stage, the entire case can crumble under constitutional scrutiny.

Reasonable Suspicion for the Initial Stop

Before an officer can activate their lights, they must have probable cause to believe a traffic infraction has occurred, or reasonable suspicion that a crime, such as DWI, is being committed. This is not a high bar, but it is more than mere instinct. The officer must rely on specific, articulable facts that would lead a reasonable person to believe something unlawful is happening.

In most DWI cases, reasonable suspicion is grounded in two common categories of observations:

• Erratic Driving: Swerving, weaving, drifting between lanes, or inconsistent braking can raise legitimate suspicion.
• Traffic Violations: Any infraction of the New York Vehicle and Traffic Law (VTL), such as speeding, running a red light, failing to signal, or driving with a broken taillight, can legally justify a stop.

It is important to note that many DWI stops begin with a pretextual violation. Under People v. Robinson, a stop is still lawful even if pretextual, as long as the officer had probable cause for the underlying traffic offense. That minor infraction becomes the legal “doorway” to a larger investigation.

This is why defense attorneys often scrutinize the validity of the stop itself. Dashcam footage, witness statements, or maintenance records may reveal that no actual violation occurred. If the initial stop was unlawful, all evidence that follows, such as field sobriety tests or breathalyzer results, can be suppressed under the fruit of the poisonous tree doctrine. When this happens, the prosecution’s case may collapse entirely.

Probable Cause for the Arrest

After a lawful stop, the officer must gather more evidence before making an arrest. Reasonable suspicion alone is not enough. To lawfully take a driver into custody for DWI, the officer must establish probable cause, a higher, constitutionally required standard.

Probable cause exists when the facts and circumstances would lead a reasonable person to believe that a crime has been committed and that the suspect is responsible. In DWI cases, this determination is made based on the totality of the circumstances. An officer’s observations and interactions during the roadside investigation form the “bridge” between reasonable suspicion and probable cause. Without enough credible evidence to cross that bridge, the arrest cannot legally stand.

Building Probable Cause

From the moment an officer approaches the driver’s side window, the collection of evidence begins. Every observation, question, and test is designed to build a record supporting the conclusion that a driver is under the influence. This process is not random; it follows a deliberate, step-by-step pattern intended to accumulate facts that justify a lawful DWI arrest under New York law.

Step 1: The Officer’s Sensory Observations

The first layer of evidence comes from what the officer can see, hear, and smell. Although these observations are inherently subjective, they often form the foundation of the probable cause argument, especially in cases where a driver later refuses a chemical test. Officers are trained to look for and document the following sensory cues:

• The Odor of Alcohol: The smell of an alcoholic beverage coming from the driver’s breath, clothing, or vehicle interior is typically the first detail recorded in the police report.
• Physical Appearance: Bloodshot, watery, or glassy eyes are routinely cited as physical indicators of intoxication.
• Speech and Demeanor: Slurred, mumbled, or incoherent speech can suggest impairment. Officers will also note whether the driver appears confused, argumentative, anxious, or unusually emotional.
• Motor Skills: Fumbling for documents, dropping a wallet, or stumbling when exiting the vehicle are documented as signs of diminished coordination.

While these details can seem convincing, they are highly subjective. Many of these traits can be attributed to fatigue, allergies, stress, or other non-alcohol-related causes. These are facts that a knowledgeable defense attorney can later use to challenge the officer’s conclusions.

Step 2: The Driver’s Statements and Admissions

After noting initial observations, the officer will usually begin a brief conversation. One of the most common and strategically significant questions asked is, “How much have you had to drink tonight?”

Many drivers assume that admitting to “just a couple of drinks” appears honest or cooperative. In reality, this type of admission often becomes one of the most powerful pieces of evidence used to establish probable cause. Even a casual acknowledgment of drinking gives the officer a documented reason to continue the investigation.

It is critical to understand that drivers have the right to remain silent. A person is not legally required to answer self-incriminating questions. Politely declining to answer does not count as an admission of guilt and can prevent potentially damaging statements from being used later in court.

Step 3: Standardized Field Sobriety Tests (FSTs)

If the officer’s suspicion continues to grow, the next stage typically involves a series of Standardized Field Sobriety Tests (FSTs). These are not straightforward “pass or fail” tasks. Instead, they are divided-attention exercises designed to measure a person’s ability to process information and maintain physical coordination at the same time, both of which are skills necessary for safe driving.

The National Highway Traffic Safety Administration (NHTSA) has approved three standardized tests:

• Horizontal Gaze Nystagmus (HGN): The driver is instructed to follow a pen or fingertip with their eyes. The officer watches for involuntary jerking of the eyeball, which can indicate impairment.
• Walk-and-Turn: The driver takes nine heel-to-toe steps along a straight line, pivots, and walks back the same way. Clues include losing balance, stepping off the line, starting too soon, or using arms for balance.
• One-Leg Stand: The driver must stand on one leg with the other foot raised about six inches off the ground while counting aloud for 30 seconds. Swaying, hopping, or putting the foot down are all considered signs of impairment.

Despite being presented as scientific, FSTs are highly subjective. Their accuracy depends on the officer’s training, the clarity of instructions, and environmental conditions such as lighting or surface stability. Age, weight, medical conditions, or even anxiety can negatively affect performance.

Step 4: The Preliminary Breath Test (PBT)

The final step of the roadside investigation often involves the Preliminary Breath Test (PBT), a handheld device used to estimate a driver’s blood alcohol content (BAC).

Under New York law, a roadside Preliminary Breath Test (PBT) is primarily a screening tool to help determine whether there is probable cause to arrest. Its numeric result is generally not admissible at trial to prove intoxication, except in rare, narrowly limited circumstances. The PBT’s legitimate purpose under VTL §1194(1)(b) is to assist the officer in deciding whether there is probable cause to make an arrest or request an official chemical test at the station. A positive PBT result, showing the presence of alcohol, is considered circumstantial support for probable cause, leading to a formal arrest and more precise chemical testing at the police station.

While a PBT reading can strengthen an officer’s case in the moment, it is far from infallible. These portable devices are prone to calibration errors, environmental interference, and misuse. An experienced defense attorney can often question the reliability and handling of the PBT to cast doubt on its role in establishing probable cause.

Step	Purpose	Limitations or Accuracy
Step 1: Sensory Observations	To gather initial observations such as smell, eyes, and behavior	Subjective; can be caused by fatigue or other conditions
Step 2: Driver’s Statements	To obtain admissions or explanations supporting suspicion	Statements may be misinterpreted or given under pressure
Step 3: Field Sobriety Tests	To assess coordination and divided attention	Accuracy varies; HGN about 77%, Walk-and-Turn 68%, One-Leg Stand 65%
Step 4: Preliminary Breath Test	To estimate blood alcohol content and justify arrest	Inadmissible at trial; prone to device or calibration errors

Long Island DWI Lawyer Jason Bassett

Understanding the Four Levels of Police Encounters (People v. De Bour)

Beyond the national standards of reasonable suspicion and probable cause, New York law has developed its own unique framework for regulating interactions between police officers and citizens. This framework was established in the landmark Court of Appeals decision People v. De Bour (1976), which created a four-tiered system outlining the permissible scope of police encounters. Each level represents an escalating degree of intrusion, and each requires a correspondingly higher level of justification.

Level 1 – Request for Information: At the lowest level, an officer may approach a person to request basic information such as identification or to inquire about their presence in a certain area. This type of encounter must be based on an objective, credible reason that is unrelated to criminal suspicion. For example, an officer may approach a parked vehicle to check on the welfare of a driver who appears to be asleep or in distress. However, the officer cannot use this level as a pretext to begin a DWI investigation without further justification.

Level 2 – Common-Law Right of Inquiry: This level allows for more pointed questioning when an officer develops a founded suspicion that criminal activity is afoot. The officer may ask questions that are more probing or investigative in nature, such as whether the person has been drinking or where they are coming from. However, the officer still lacks authority to detain or physically control the person. The interaction must remain voluntary, and the individual is free to leave.

Level 3 – Investigative Detention (Terry Stop): Once an officer develops reasonable suspicion that a specific individual has committed, is committing, or is about to commit a crime, they may temporarily detain that person for investigative purposes. In the context of a DWI stop, this typically occurs when the officer observes erratic driving or a traffic violation that justifies pulling the vehicle over. At this level, the officer may direct the driver to remain in the vehicle, request documentation, and make initial observations for signs of intoxication.

Level 4 – Arrest Based on Probable Cause: The final and most intrusive level is an arrest, which requires probable cause, a reasonable belief that a crime has been committed and that the suspect is responsible. For DWI cases, this determination is usually made after the officer completes field sobriety tests, notes clear indicators of impairment, or receives a positive reading from a preliminary breath test. Once probable cause is established, the officer is legally authorized to take the driver into custody.

The De Bour levels show that a DWI investigation is not a single, uninterrupted event. Instead, it is a series of escalating encounters, each of which must be legally justified before moving to the next. A constitutional violation at any step can break the chain of legality, potentially invalidating everything that follows.

New York’s “Common Law” DWI (VTL § 1192.3)

Many people believe that a DWI charge requires a chemical test result showing a Blood Alcohol Content (BAC) of 0.08% or higher. While this is one way to prove DWI, known as “DWI per se” under VTL § 1192.2, prosecutors in New York have another powerful tool: VTL § 1192.3.

This statute, often referred to as “Common Law” DWI, makes it illegal to operate a motor vehicle while in an intoxicated condition. Unlike per se DWI, this law does not define intoxication with a specific BAC number. Instead, a driver is considered intoxicated if they have consumed alcohol to the extent that they are incapable of using the physical and mental abilities required to operate a vehicle as a reasonable and prudent driver.

Under a Common Law DWI charge, the same evidence an officer gathers to establish probable cause for the arrest becomes the key evidence the prosecution relies on at trial. The case is built almost entirely on the officer’s observations and testimony, including:

• Erratic driving behavior
• The driver’s physical appearance and demeanor
• Slurred or incoherent speech
• Poor performance on field sobriety tests
• Any incriminating statements made at the scene

Because no chemical test is needed, the credibility of the officer’s account becomes central to the prosecution’s case.

The “Refusal” Connection

Common Law DWI charges are most often brought when a driver refuses to submit to a chemical test, such as a breath, blood, or urine test at the police station. Although a driver has the right to refuse, that decision comes with serious consequences.

• Administrative Penalties: A refusal immediately triggers a separate administrative hearing with the Department of Motor Vehicles (DMV). Even if the criminal case is later dismissed, the DMV proceeding almost always results in a mandatory one-year revocation of the driver’s license.
• Consciousness of Guilt: At the criminal trial, the prosecutor is allowed to inform the jury that the driver refused the chemical test. The jury may, but is not required to, interpret that refusal as evidence of consciousness of guilt, meaning the driver declined testing because they believed the results would confirm intoxication.

A driver who refuses chemical testing is placed in a difficult strategic position. On one hand, they deny the prosecution scientific proof of a BAC reading, which is often the most persuasive evidence in DWI cases. On the other hand, the absence of that data shifts the entire case onto the officer’s subjective observations.

Protect Your Rights with the Legal Help of an Experienced Long Island DWI Lawyer

A DWI charge in New York can have serious and lasting consequences, but it is not the same as a conviction. Every stage of a DWI case, from the initial stop to the arrest and testing procedures, must meet strict legal standards. When law enforcement fails to follow these rules, the evidence they collect can often be challenged and even thrown out. Knowing what counts as probable cause for a DWI arrest can make all the difference in how your case unfolds.

If you are facing DWI charges, do not leave your future to chance. Long Island DWI lawyer Jason Bassett at The Law Offices of Jason Bassett, P.C. provides skilled and strategic defense for clients throughout Long Island and across New York. He can thoroughly examine the details of your stop, arrest, and testing to uncover any violations of your rights. To discuss your case and learn more about what counts as probable cause for a DWI arrest in New York, call (631) 259-6060 today for a free and confidential consultation.