In New York, a Driving While Intoxicated (DWI) conviction requires prosecutors to present specific evidence showing that you operated a vehicle while impaired. Blood Alcohol Content (BAC) test results serve as the primary evidence, but prosecutors also rely on field sobriety tests, officer testimony, video footage, and police reports. The strength and reliability of this evidence directly affect whether charges result in conviction, reduction, or dismissal.
At the Law Offices of Jason Bassett, P.C.,Suffolk County DWI defense attorney Jason Bassett scrutinizes every piece of prosecution evidence. With over 21 years of criminal law experience, including service as a former prosecutor, Attorney Bassett understands how prosecutors build cases and where those cases can be challenged.
This guide explains what BAC evidence prosecutors need, how field sobriety tests can be contested, why witness testimony matters, and what defenses may be available in your case. Call the Law Offices of Jason Bassett, P.C. at (631) 259-6060 to speak with Long Island criminal defense attorney Jason Bassett about your DWI charges.
What Is Blood Alcohol Content Evidence?
Blood Alcohol Content (BAC) measures the concentration of alcohol in your bloodstream. New York Vehicle and Traffic Law (VTL) § 1192 sets the legal limit at 0.08% for most drivers. Commercial drivers face a stricter limit of 0.04% due to the increased responsibility they carry. Exceeding these limits provides prosecutors with strong evidence for a DWI conviction.
BAC testing uses three primary methods. Blood tests directly measure alcohol concentration in the bloodstream and are considered highly accurate. Breath tests use a breathalyzer device to estimate BAC based on the alcohol content in your breath, which correlates to blood levels. Urine tests are less commonly used because they indicate the presence of alcohol metabolites over a longer period rather than immediate impairment levels.
Each testing method must follow specific protocols. The New York State Department of Health establishes calibration requirements for breathalyzer devices. Blood samples require proper collection, storage, and chain of custody documentation. Any deviation from these protocols can compromise test accuracy and admissibility in court.
New York’s implied consent law under VTL § 1194 requires drivers to submit to chemical testing when lawfully arrested for DWI. Refusing a chemical test triggers an automatic license suspension and can be used as evidence against you at trial. The consequences of refusal are often as serious as the DWI charge itself.
| BAC Testing Method | How It Works | Accuracy Level | Common Challenges |
|---|---|---|---|
| Blood Test | Directly measures alcohol concentration in the bloodstream | Highly accurate when properly administered | Chain of custody issues, improper storage, and sample contamination |
| Breath Test (Breathalyzer) | Estimates BAC based on alcohol content in breath | Generally reliable with proper calibration | Calibration errors, operator mistakes, medical conditions (diabetes), and environmental interference |
| Urine Test | Detects alcohol metabolites over an extended period | Less precise for immediate impairment | Timing issues, doesn’t reflect BAC at time of driving, storage problems |
How Accurate Are BAC Tests?
BAC test accuracy depends on proper calibration, operator training, and testing conditions. Multiple factors can produce inaccurate results that may lead to false DWI charges.
Calibration and Maintenance Issues
Breathalyzer devices require regular calibration to ensure accurate readings. New York regulations require that approved breath-testing instruments be maintained and calibrated at least once a year or as often as the manufacturer recommends. When police agencies ignore these requirements or keep poor maintenance records, defense attorneys can challenge whether the results are reliable enough to use in court. Blood and urine testing equipment also requires proper calibration and maintenance to produce accurate and reliable measurements.
Operator Error
The person administering the test must follow established protocols. Improper sample collection, incorrect device operation, or failure to observe the defendant for the required period before testing can all compromise results. Defense attorneys can challenge evidence when operators lack proper training or when testing procedures deviate from approved methods.
Physiological and Environmental Factors
Individual health conditions affect BAC readings. Diabetes and diabetic ketoacidosis can cause high levels of acetone and other ketones in a person’s breath, and some breath-testing devices may misread those chemicals as alcohol. Certain diets and medical treatments also influence how the body processes alcohol. Environmental factors such as chemical fumes or solvents near the testing area can interfere with breath tests and produce falsely elevated readings.
Sample Integrity and Chain of Custody
Blood and urine samples must be properly stored and preserved. Contamination, improper storage temperatures, or testing delays can cause fermentation or degradation, altering the alcohol concentration. Every person who handles the sample must be documented in the chain of custody. Any break or ambiguity in this documentation provides grounds for questioning the sample’s authenticity.
Timing Considerations
The timing of tests affects their reliability. Alcohol absorption rates vary, and testing too early or too late after alleged driving can provide misleading BAC levels. Defense attorneys can argue that the BAC at the time of testing differed significantly from the BAC at the time of driving.
Key Takeaway: BAC test accuracy depends on calibration, proper procedures, and a documented chain of custody. Errors in any of these areas create opportunities for defense attorneys to challenge the reliability of prosecution evidence.
Jason Bassett can review your BAC test procedures and identify potential challenges. Call (631) 259-6060 for a case evaluation.
DWI Defense Attorney on Long Island – Law Offices of Jason Bassett, P.C.
Jason Bassett, Esq.
Jason Bassett is a Suffolk County DWI defense attorney and former prosecutor with over 21 years of criminal law experience. 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, and Principal Assistant County Attorney for Suffolk County. He also served as an Assistant District Attorney in Queens County from 1999 to 2001. This background on both sides of the courtroom gives him insight into how prosecutors build DWI cases and where those cases can be challenged.
Mr. Bassett earned his Juris Doctor from Boston College Law School in 1999 and his Bachelor of Arts from the University of Pennsylvania in 1994. He is admitted to practice in New York State and the United States District Courts for the Eastern and Southern Districts of New York, as well as the United States Court of Appeals for the Second Circuit. He defends clients at both the state and federal levels throughout Suffolk County and Nassau County.
What Are Field Sobriety Tests?
Field sobriety tests (FSTs) are physical and cognitive exercises that officers use to assess impairment during a traffic stop. Law enforcement on Long Island commonly administers several standardized tests during DWI investigations.
The Horizontal Gaze Nystagmus (HGN) test involves an officer observing the driver’s eyes as they follow a moving object such as a pen or flashlight. The Walk-and-Turn test requires the suspect to walk nine steps heel-to-toe along a straight line, turn on one foot, and return in the same manner. The One-Leg Stand test involves standing on one leg at a specific height, usually six inches from the ground, for a specified duration.
Officers may also administer the Romberg Balance Test, which requires standing with feet together, arms at sides, head tilted back, and eyes closed while estimating the passage of 30 seconds. The Finger to Nose Test involves closing your eyes and touching the tip of your nose with the tip of your index finger. These tests measure balance, coordination, and the ability to follow instructions.
The National Highway Traffic Safety Administration (NHTSA) has validated three standardized field sobriety tests: the Horizontal Gaze Nystagmus, Walk-and-Turn, and One-Leg Stand as tools to help officers detect impairment. However, even these NHTSA-approved tests, and other non-standardized tests like the Romberg Balance Test and Finger to Nose Test, can be affected by factors unrelated to alcohol consumption. Uneven road surfaces, poor weather conditions, physical conditions such as injuries or disabilities, and subjective officer judgment all influence test results. What one officer considers a “fail” might not be viewed the same by another, introducing personal bias into the determination of impairment.
Unlike breath tests, you are not legally required to participate in field sobriety tests in New York. However, refusing a field sobriety test may be presented at trial as “consciousness of guilt.” Defense attorneys can challenge field sobriety test results by arguing that tests were not conducted under reasonable conditions or that the officer lacked proper training to administer and evaluate them accurately.
How Does Witness Testimony Impact DWI Cases?
Witness testimony plays a significant role in DWI prosecutions and defenses. The credibility and reliability of witnesses directly affect case outcomes.
Officer Testimony
The arresting officer’s testimony is often central to the prosecution’s case. Officers testify about your driving behavior, physical appearance, performance on field sobriety tests, and results of preliminary breath tests conducted at the scene. Their accounts aim to establish probable cause for the arrest and provide firsthand observations of your condition at the time of the stop.
Officer testimony carries significant weight but is also subject to rigorous scrutiny. Defense attorneys use cross-examination to uncover inconsistencies in statements, potential biases, or factors affecting observations, such as poor visibility or lack of training. Effective cross-examination can cast doubt on the prosecution’s narrative.
Civilian Witnesses
Civilian witnesses can either support the prosecution or aid the defense. Individuals who observed you before getting behind the wheel can offer insights into your alcohol consumption or behavior. Passengers or bystanders who witnessed the arrest might provide testimony regarding your behavior or the conduct of the arrest itself.
Civilian witness testimony adds depth to the case narrative. Defense attorneys can use these witnesses to contradict prosecution claims or to demonstrate that observed behavior had explanations other than alcohol impairment.
Key Takeaway: Witness testimony from both law enforcement and civilians significantly influences DWI case outcomes. Cross-examination of witnesses can reveal inconsistencies, biases, or alternative explanations that strengthen the defense.
Suffolk County DWI defense attorney Jason Bassett can effectively cross-examine witnesses to challenge prosecution testimony. Call (631) 259-6060 for representation.
What Role Does Video Evidence Play?
Video evidence has become an important part of DWI prosecutions and defenses. Dashboard cameras can show the initial traffic stop, your interaction with the officer, and any field sobriety tests done on the scene. Body cameras worn by officers provide a closer look at conversations and movements, while surveillance videos from nearby businesses or traffic cameras can offer additional angles. This footage captures your behavior, verbal responses, and physical coordination. It gives a visual and audio record that may support or contradict the officer’s testimony, and lawyers review it to evaluate whether the stop, the tests, and the arrest followed proper procedures and respected your rights.
Video can strongly affect how a DWI case is resolved. When the footage supports the officer’s version of events, it can strengthen the prosecution’s case. When it shows inconsistencies with the police report or suggests that field sobriety tests were explained or administered incorrectly, it can become a powerful tool for the defense. Because video evidence gives both sides clear, tangible evidence to work with, it also plays a major role in plea negotiations and in deciding whether to fight the charges at trial.
What Information Do Police Reports Contain?
Police reports are the formal record of a DWI arrest. Written by the arresting officer, they describe why you were stopped, what the officer observed about your driving and behavior, and how you performed on field sobriety tests. Reports also note details like the scene, weather, lighting, and traffic conditions, and may include photos, diagrams, and officer notes that help prosecutors, defense attorneys, judges, and juries understand what happened.
The thoroughness and accuracy of this documentation can strongly affect your case. Prosecutors rely on a clear, consistent report to support the DWI charge, while defense attorneys study the same report for missing details, contradictions, or procedural errors that may show your rights were violated or that the officer’s conclusions were unreliable. Inconsistencies or gaps in the report create opportunities to challenge the prosecution’s evidence, influence plea negotiations, and even affect trial or appeal outcomes.
What Legal Defenses Can Challenge DWI Charges?
New York law provides several defenses against DWI charges. Effective defense strategies can lead to reduced charges, acquittal, or other favorable outcomes.
Procedural Defenses
Procedural defenses focus on the legality of the arrest process and the rights of the accused. If law enforcement failed to read Miranda rights at the appropriate time, certain statements you made may be inadmissible in court. Administrative errors related to BAC testing or failure to adhere to standardized procedures for sobriety testing can also serve as grounds for challenging the charge.
Procedural defenses question the integrity of the evidence and safeguard your constitutional rights. Courts in Suffolk County have dismissed cases where prosecutors failed to prove that proper procedures were followed.
Substantive Defenses
Substantive defenses contest the factual basis of the charges. Defense attorneys may argue that you were not actually impaired or that external factors contributed to the appearance of impairment. Physical disabilities or medical conditions can sometimes mimic symptoms of intoxication.
Defense attorneys can also contest the accuracy or reliability of chemical tests by questioning the time between the arrest and test administration, or by providing alternative explanations for the presence of alcohol or drugs in your system. These defenses aim to undermine the prosecution’s claim that you were operating a vehicle under the influence.
Key Takeaway: Both procedural and substantive defenses provide opportunities to challenge DWI charges in New York. Experienced defense representation can identify violations of rights or errors in evidence that may result in charge reduction or dismissal.
Attorney Jason Bassett examines every aspect of your case to build the strongest possible defense. Contact the Law Offices of Jason Bassett, P.C. at (631) 259-6060.
Protect Your Rights with a Suffolk County DWI Attorney
Facing DWI charges on Long Island carries serious consequences, including fines, license suspension, and potential jail time. The evidence against you may seem overwhelming, but prosecutors must prove every element of the charge beyond a reasonable doubt. Errors in BAC testing, improper field sobriety test administration, and violations of your rights can all affect the case outcome.
Jason Bassett has defended hundreds of DWI cases throughout Suffolk County and Nassau County. The Law Offices of Jason Bassett, P.C. handles cases in Suffolk County Court, district courts throughout the county, and town courts in communities such as Islip, Smithtown, and Brookhaven. The firm thoroughly investigates BAC test procedures, challenges field sobriety test results, and cross-examines prosecution witnesses. As a former prosecutor, Jason Bassett understands how the Suffolk County District Attorney’s Office builds cases and how to identify weaknesses in the evidence.
Call the Law Offices of Jason Bassett, P.C. at (631) 259-6060 for a consultation. OurCentral Islip office serves clients throughout Suffolk County, Nassau County, and Long Island. Jason Bassett can review the evidence, explain your legal options, and work to protect your driving privileges and your future.