Breathalyzer tests are a central tool law enforcement uses to enforce DWI laws on Long Island. These devices measure blood alcohol content (BAC) by analyzing breath samples. A reading at or above the legal limit can lead to arrest and criminal charges. However, breathalyzers are not perfect. Device malfunctions, improper administration, and physiological factors can produce inaccurate results.
If you are facing DWI charges in Suffolk County, understanding how breathalyzer evidence works and how it can be challenged is essential. At the Law Offices of Jason Bassett, P.C., Suffolk County criminal defense attorney Jason Bassett has defended hundreds of clients against drunk driving charges. As a former prosecutor with more than 20 years of criminal law experience, he understands how breathalyzer results are used in court and where weaknesses in the evidence may exist. Our Long Island DWI and DUI defense lawyer serves clients throughout Long Island and New York.
This guide explains how breathalyzers work, legal BAC limits in New York, factors that affect accuracy, and how you can challenge breathalyzer results in court. You will also learn about the consequences of refusing a breathalyzer test and what happens to your license after a DWI charge. Call the Law Offices of Jason Bassett, P.C. at (631) 259-6060 to discuss your case.
What Are the Legal BAC Limits in New York?
New York law sets specific blood alcohol concentration (BAC) thresholds for different types of drivers. A BAC of 0.08% or higher is the standard per se limit for drivers aged 21 and older. Commercial drivers face a stricter standard at 0.04% in a vehicle requiring a Commercial Driver’s License (CDL). For drivers under 21, New York’s Zero Tolerance framework is triggered at 0.02% to 0.07% BAC, and higher BAC levels may expose an underage driver to additional charges depending on the facts.
These limits are not absolute. You can still face DWI charges if your BAC is below 0.08%, but you exhibit impaired driving. Officers may arrest you based on observed behavior such as erratic driving, slurred speech, or failed field sobriety tests. A BAC reading of 0.08% or higher does not guarantee a conviction either. The accuracy of the breathalyzer test and the procedures used during testing can be challenged in court.
A BAC of 0.18% or higher triggers an Aggravated DWI charge in New York. This carries enhanced penalties, including higher fines, longer license revocations, and mandatory ignition interlock device (IID) installation. Understanding these thresholds is important because the level of your BAC directly affects the severity of the charges you face.
| Driver Type | BAC Limit | Legal Standard |
|---|---|---|
| Standard Drivers (21+) | 0.08% | Driving While Intoxicated (DWI) |
| Commercial Drivers | 0.04% | Lower threshold for CDL holders |
| Underage Drivers (Under 21) | 0.02% | Zero Tolerance Law |
| Aggravated DWI | 0.18% | Enhanced penalties apply |
How Do Breathalyzers Detect Alcohol Levels?
Breathalyzers operate on the principle that alcohol concentration in your breath correlates with alcohol concentration in your blood. This relationship is based on Henry’s Law, which states that the amount of alcohol in the air within your lungs is proportional to the amount in your bloodstream. When you breathe into a breathalyzer, the device measures the alcohol in your exhaled breath to estimate your BAC.
Modern breathalyzers use different technologies to detect alcohol. Traditional devices rely on a chemical reaction with a chromogenic agent such as potassium dichromate. When ethanol in your breath contacts this chemical solution, it oxidizes the dichromate and causes a color change. The device measures this color change and converts it into a BAC reading.
Infrared spectroscopy is another common method used in modern breathalyzers. Infrared light passes through the breath sample, and alcohol molecules absorb specific wavelengths of this light. The device measures the amount of light absorbed, which directly correlates with the alcohol present in the breath. This method is non-reactive and is known for accuracy.
Portable breathalyzers often use electrochemical fuel cell technology. In these devices, alcohol in the breath sample undergoes a chemical oxidation reaction at the surface of a fuel cell. This reaction produces protons and electrons, generating an electrical current that flows from the anode to the cathode. The strength of this current is proportional to the amount of alcohol in the breath sample and thus to the driver’s BAC.
DWI Defense Attorney in Suffolk County – Law Offices of Jason Bassett, P.C.
Jason Bassett, Esq.
Jason Bassett, Esq., is a Suffolk County DWI defense attorney and former prosecutor with more than 20 years of criminal law experience. He earned his J.D. from Boston College Law School in 1999 and his B.A. from the University of Pennsylvania in 1994. His career includes service as Special Assistant Attorney General in the New York Medicaid Fraud Control Unit, Chief Deputy Commissioner for the Town of Islip Department of Public Safety Enforcement, Principal Assistant County Attorney for Suffolk County, and Assistant District Attorney for Queens County. This background on both sides of the courtroom gives him unique insight into how prosecutors build DWI cases and where those cases can be challenged.
Mr. Bassett defends clients at both the state and federal levels throughout Suffolk County and Nassau County. He served as President of the Suffolk County Criminal Bar Association for 2024-2025. Clients value his thorough case preparation and ability to negotiate with local prosecutors he has worked alongside for decades.
What Factors Affect Breathalyzer Accuracy?
Breathalyzer accuracy depends on proper calibration, correct administration, and the absence of interfering factors. Even when devices function correctly, various physiological and environmental factors can skew results. Understanding these factors is important when challenging breathalyzer evidence in court.
Calibration Errors
Calibration is critical to breathalyzer accuracy. New York law requires regular calibration and maintenance of these devices according to manufacturer specifications and state regulations. If a breathalyzer is not calibrated on schedule, it can produce false readings. Defense attorneys often scrutinize calibration records to identify errors. A device that was overdue for calibration or improperly maintained may have produced an unreliable BAC reading.
Physiological Factors
Several physiological factors can influence breath-test results. Research shows that breathing pattern and the manner of exhalation can affect measured breath-alcohol concentration. For example, some breathing maneuvers can produce lower measured BAC. Forensic literature also discusses how breath temperature and body temperature relate to the blood/breath relationship used in breath testing.
Alcohol retention in the mouth is another factor. If alcohol is present in your mouth due to recent drinking, belching, or regurgitation, it can result in a higher BAC reading than your actual blood alcohol level. This is why New York’s breath-testing rules require at least 15 minutes of observation before collecting a breath sample.
External Factors
Potential external influences are often device-specific and usually litigated by focusing on whether the instrument was validated for known interferents and operated per protocol. For example, forensic literature and standards discuss chemical interferents such as acetone (which can be elevated in some physiological states) and the importance of using properly approved/testing-validated instruments.
Diet and Medical Conditions
Certain medical or physiological conditions can introduce issues that are often litigated as “interferents” or “mouth alcohol” scenarios. For example, forensic sources discuss acetone as a potential interferent, and the real-world significance depends on the instrument’s design and validation against interferents. Conditions associated with regurgitation or reflux are frequently raised because they can increase the risk of mouth alcohol contamination, which is why observation and protocol compliance are central to evidentiary breath testing.
How Is a Breathalyzer Test Administered in New York?
New York law establishes strict procedures for administering breathalyzer tests. These procedures are designed to ensure accurate and reliable results.
Observation Period
Before collecting an evidentiary breath sample, New York breath-testing rules require that the subject be observed for at least 15 minutes, during which the subject must not ingest fluids, eat, smoke, vomit/regurgitate, or place anything in the mouth; if any of those occur, an additional observation period is required before sampling.
Device Preparation
The breathalyzer device must be properly calibrated and maintained according to manufacturer specifications and New York state regulations. The officer should ensure that the device is functioning correctly and that no residual alcohol is present from previous tests. A properly functioning device is essential to obtaining accurate readings.
Test Instructions and Sample Collection
The test subject receives clear instructions on how to blow into the device. This typically involves a single, continuous breath until the officer indicates to stop. The officer must ensure that an adequate breath sample is collected for analysis. This usually requires a deep lung sample to provide the most accurate correlation to blood alcohol content. Once the breath sample is analyzed, the breathalyzer displays the BAC level. This result is recorded, and a copy is generally provided to the suspected driver.
Common Administration Mistakes
Mistakes can occur during breathalyzer test administration. An insufficient observation period can lead to contaminated results if the driver has ingested or regurgitated substances that affect mouth alcohol levels. Improper calibration can produce false results, which is why regular calibration and maintenance are necessary. Radio frequency interference from police radios or other electronic devices can sometimes affect breathalyzer function. Certain medical conditions or dietary factors can affect test results, and officers must account for these when administering the test. Not following the correct procedure, such as failing to give clear instructions or not waiting long enough between tests, can lead to inaccurate BAC readings.
Key Takeaway: Proper breathalyzer administration in New York requires at least 15 minutes observation period, a correctly calibrated device, clear instructions to the test subject, and adequate breath sample collection. Common errors include insufficient observation, improper calibration, electronic interference, and failure to account for medical conditions. These procedural mistakes can invalidate breathalyzer results.
Jason Bassett can review the administration procedures used in your case to identify potential violations. Contact (631) 259-6060 for a consultation.
Can You Challenge Breathalyzer Results in Court?
Yes, breathalyzer results can be challenged in court. Defense attorneys can contest the accuracy and reliability of breathalyzer evidence for a variety of reasons. Successfully challenging these results can lead to them being excluded from evidence or given less weight by the court, which can significantly impact the outcome of your case.
- Calibration and maintenance records are often the first area of challenge. If the defense can show that the breathalyzer was improperly calibrated or not maintained according to state regulations, the results may be deemed unreliable. Regular calibration and maintenance are necessary for accurate readings, and any lapse in these requirements can undermine the prosecution’s case.
- Administration procedures are another common challenge. If the test was not administered correctly, the results may be contested. Examples include failure to observe the required observation period, improper instructions to the test subject, or not ensuring an adequate breath sample was collected. Each of these procedural errors can affect the accuracy of the BAC reading.
- Medical and dietary factors can also provide grounds for challenging breathalyzer results. A defense attorney might introduce evidence that a medical condition, such as GERD or diabetes, could have skewed the results. Low-carbohydrate diets that produce ketones in the breath can lead to false positives. The presence of these factors calls into question the accuracy of the breathalyzer reading.
- Radio frequency interference and environmental contamination are additional challenges. If the breathalyzer was exposed to electronic interference from police radios or cell phones, the reading may be inaccurate. Similarly, exposure to chemicals like paint fumes or cleaning products can produce false readings.
What Happens If You Refuse a Breathalyzer Test on Long Island?
Under New York’s implied consent law, drivers are deemed to have consented to a chemical test for alcohol if they are arrested for suspected DWI. Refusing to submit to a breathalyzer test on Long Island can lead to immediate penalties, regardless of whether you are subsequently found guilty of DWI.
Immediate License Suspension
If you refuse a chemical test, NY DMV materials explain that your license is suspended at arraignment, and if the refusal is upheld, your license is revoked at a DMV refusal hearing for at least one year (second offense: 18 months), along with separate civil penalties.
Fines and Civil Penalties
Drivers who refuse the test face a civil penalty of $500 for a first refusal. For a second refusal or a refusal within five years of a previous DWI-related charge, the civil penalty increases to $750. These fines are separate from any criminal penalties you may face if convicted of DWI.
Evidence in Court
The fact that you refused a breathalyzer test can be introduced as evidence in court. Prosecutors may use your refusal to imply consciousness of guilt. While refusal does not guarantee a DWI conviction, it can be used against you during trial. Prosecutors may still pursue a conviction based on other evidence of impairment, such as officer observations, field sobriety test results, and driving behavior.
DMV Hearings
After a breathalyzer refusal, the DMV schedules a hearing to determine whether the refusal was valid. At this hearing, you can present evidence to challenge the refusal. However, if the DMV finds that the refusal was valid, your license revocation will stand. Even if you qualify for the Impaired Driver Program, you may not be eligible for a conditional license if the DMV finds a valid chemical test refusal.
Talk to a Suffolk County DWI Attorney Today
Facing DWI charges based on breathalyzer evidence can be overwhelming. The consequences of a conviction include fines, jail time, license revocation, and long-term impacts on your employment and personal life. Understanding how breathalyzer tests work and where errors can occur is essential to building a strong defense.
Jason Bassett has defended clients against DWI charges throughout Suffolk County and Long Island for more than 20 years. As a former prosecutor and Special Assistant Attorney General, he knows how DWI cases are prosecuted and where weaknesses in the evidence can be exploited. At the Law Offices of Jason Bassett, P.C., he handles every aspect of DWI defense, including challenging breathalyzer results, negotiating with prosecutors at the Suffolk County First District Court in Central Islip, and representing clients at DMV hearings.
Call the Law Offices of Jason Bassett, P.C. at (631) 259-6060 for a consultation. Our office in Central Islip serves clients throughout Suffolk County and Nassau County. We will review the breathalyzer evidence in your case, examine calibration records and testing procedures, and provide the aggressive defense you need to protect your rights and your future.