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Clarifying DWI Arrests Without a Failed Breath Test in New Hampshire
In New Hampshire, many drivers assume that a failed breath test is the only way to get arrested for DWI (Driving While Intoxicated). However, that’s not the case. Law enforcement officers do not need a failed chemical test to make an arrest. They rely on a range of observations and evidence to determine whether someone is impaired. A driver can, in fact, be arrested without ever blowing over the legal limit—or without taking a breath test at all.
This situation is more common than many people realize. While breath tests are a standard tool in DWI investigations, they are just one part of a much broader decision-making process. Officers are trained to evaluate a driver’s behavior, appearance, speech, and physical coordination. If those signs suggest impairment, an arrest may occur even if a chemical test has not confirmed intoxication.
This post explores how DWI arrests happen in New Hampshire without failed breath tests, how officers build probable cause, what role field sobriety tests play, and why chemical test refusal can still lead to consequences. Understanding this process offers clarity on how DWI enforcement works and dispels the myth that breath tests are the only factor involved.
The Legal Standard: Probable Cause, Not Just BAC
In New Hampshire, a DWI arrest is based on probable cause—not on a failed breath test alone. Probable cause means that an officer has a reasonable basis to believe a person is driving under the influence based on observable facts and evidence.
This evidence can include:
- Erratic or dangerous driving
- The smell of alcohol
- Slurred speech or delayed responses
- Bloodshot or watery eyes
- Difficulty standing, walking, or speaking clearly
- Confusion or inability to follow instructions
If these signs are present during a stop, an officer may determine that the driver is impaired—even if the person hasn’t taken or failed a breath test. The law does not require a BAC reading to arrest someone for DWI, only enough credible evidence that impairment exists.
In practice, this means that a breath test is supportive, not mandatory. It may strengthen an officer’s case, but it’s not required for the arrest itself to be legal or valid.
Field Sobriety Tests as a Key Factor
One of the primary tools officers use when a breath test is not available or not failed is the Standardized Field Sobriety Test (SFST). These tests are designed to assess both physical coordination and mental focus.
In New Hampshire, the three main SFSTs are:
- Horizontal Gaze Nystagmus (HGN) – Examines involuntary eye movement
- Walk-and-Turn – Evaluates balance and the ability to follow multi-step instructions
- One-Leg Stand – Measures balance and focus
Poor performance on these tests can strongly support an officer’s decision to arrest someone for DWI. Even if the person later passes a chemical test, the arrest itself can still stand if the officer had valid probable cause at the time based on SFST results and observed behavior.
These tests are especially important in situations where a driver refuses a breath test or when breath test results are not immediately available. They provide real-time, observable evidence of impairment.
Refusal to Take a Breath Test Still Has Consequences
New Hampshire enforces an implied consent law, which means that any person who drives in the state is deemed to have given consent to chemical testing (breath, blood, or urine) after a lawful DWI arrest.
Refusing to take a chemical test does not prevent a DWI arrest, and in fact, refusal:
- Can still lead to arrest based on other evidence
- Automatically results in administrative license suspension
- May be used as evidence against the driver in court
In other words, refusing to take a breath test doesn’t protect a driver from arrest—it simply changes the type of evidence the state uses and triggers immediate administrative penalties, even before a court case begins.
Arrests Based on Drug Impairment or Other Substances
Another important factor is that not all DWI arrests involve alcohol. Drivers under the influence of prescription drugs, illegal substances, or even over-the-counter medications may show signs of impairment without having any alcohol in their system at all.
In such cases, breath tests may return a 0.00% BAC, but the driver may still be arrested based on signs of impairment and further toxicology testing (typically blood or urine).
Common indicators of drug impairment include:
- Pupil dilation or constriction
- Unusual body movements
- Slow reaction time
- Disorganized thoughts or speech
New Hampshire law makes no distinction in arrest standards between alcohol and other substances. If a driver is impaired by any drug or combination of substances, they may be arrested for DWI—even without any alcohol present in a breath test.
The Role of Officer Observations and Training
New Hampshire law enforcement officers are trained to recognize signs of impairment that go beyond what a device can detect. They use a combination of standard procedures, intuition, and experience to build a case for probable cause.
These observations may be documented in:
- Dashcam footage
- Body camera recordings
- Officer reports
- Witness accounts
- Physical evidence (such as open containers or paraphernalia)
This collection of evidence is often strong enough to support a DWI arrest, even in the absence of failed breath test results. Officers may also call in Drug Recognition Experts (DREs) in more complex cases where non-alcohol impairment is suspected.
The takeaway is that human judgment, not just machines, drives arrest decisions—especially when impairment signs are clearly present.
Can You Be Convicted Without a Failed Breath Test?
While the focus of this post is arrest—not conviction—it’s worth noting that a DWI conviction can still occur without a failed breath test, although it depends on the total weight of the evidence.
In court, prosecutors may use:
- Field sobriety test results
- Officer testimony
- Dashcam/bodycam footage
- Witness statements
- Physical behavior and conduct
- Refusal to take a test as circumstantial evidence
However, the lack of a failed chemical test may make conviction more difficult. The burden of proof is higher in court than at the roadside, so prosecutors must rely on clear and convincing documentation of impairment.
Still, drivers should not assume they are safe from consequences simply because they passed or refused a breath test. The law provides multiple avenues for enforcement and prosecution.
FAQ: DWI Arrests Without a Failed Breath Test
Can I be arrested in New Hampshire if I pass a breath test?
Yes. If officers observe signs of impairment and have probable cause, they can arrest you even if your BAC is below 0.08%.
What happens if I refuse a breath test?
Refusal triggers automatic license suspension under New Hampshire’s implied consent law and can still lead to arrest.
Do officers need a breath test to arrest me?
No. A breath test is one tool among many. Officer observations, field tests, and other signs of impairment can justify an arrest.
What if I have a medical condition that affects field sobriety test performance?
You can inform the officer, but they may still proceed based on the total circumstances. Medical conditions may be considered during legal proceedings.
Can I be arrested for drug impairment even with a 0.00% BAC?
Yes. DWI laws in New Hampshire apply to impairment from alcohol, drugs, or a combination of both.
Does passing a breath test mean the charges will be dropped?
Not necessarily. If other evidence supports the officer’s belief that you were impaired, the case can still move forward.
Are breath tests always accurate?
Breathalyzers are calibrated devices, but factors like improper usage or medical conditions may affect results. However, they are generally accepted as reliable tools.
Conclusion: Breath Test Results Aren’t the Only Factor in New Hampshire DWI Arrests
New Hampshire’s DWI enforcement strategy is rooted in observational evidence and officer training, not just breath test devices. A driver can be arrested without failing a breath test if other signs of impairment are present, and refusing a test doesn’t prevent consequences. Understanding this framework is essential for anyone who wants a clearer picture of how DWI laws function in real situations.
To get a complete picture of how DWI laws operate in New Hampshire, including definitions and enforcement processes, see our guide on How DUI Laws Work.
For a deeper look at the specific signs officers watch for during stops, visit What Triggers a DUI Arrest During a Traffic Stop.