A drunk driving charge in Philadelphia, the surrounding Philly suburbs, or anywhere in Pennsylvania brings life-altering consequences. After all, DUIs come with steep fines, jail time, license suspension, and even job loss.
With so much at stake, it’s vital to question the reliability of the tests used to determine your blood alcohol content (BAC). Breathalyzers, for instance, don’t directly measure BAC—they estimate it—making them susceptible to inaccuracies from improper calibration, operator errors, medical conditions, and environmental factors.
At Fienman Defense, we combine deep experience, particularly in Pennsylvania DUI law, with advanced training and insight into DUI testing science. Certified in the same Standardized Field Sobriety Test (SFST) training as law enforcement officers, attorney Michael Fienman knows how to uncover testing errors and procedural flaws. This lets us challenge unreliable evidence and build a defense that protects your rights and future.
The Basics of DUI Testing in PA
DUI testing methods generally fall into four categories: field sobriety tests, breath tests, blood tests, and urine tests. Each plays a unique role in determining a person’s level of impairment, with varying levels of reliability.
Field sobriety tests involve physical and cognitive tasks to assess balance, coordination, and reaction time. While widely used during traffic stops, these tests are subjective and prone to error due to anxiety, fatigue, or medical conditions.
“Scientific methods” such as breath, blood, and urine tests often provide more objective measurements. Since the landmark Birchfield v. North Dakota decision, law enforcement has increasingly relied on breath tests due to their perceived convenience and reduced constitutional concerns compared to blood draws, which typically require a warrant.
How Do Breathalyzers Work?
Breathalyzers estimate BAC by analyzing the concentration of alcohol in exhaled air. The device uses this measurement to calculate an approximate BAC based on an assumed correlation between breath and blood alcohol. However, this process has limitations. Breath alcohol content can be influenced by residual substances in the mouth, certain medical conditions, and even environmental factors, leading to inaccuracies.
Unlike blood tests, which directly measure alcohol in the bloodstream, breath tests rely on averages that may not accurately reflect an individual’s level of impairment. This makes it critical to scrutinize the reliability of breathalyzer results in DUI cases.
Breath Testing Devices in Pennsylvania
In Pennsylvania, there are two primary types of breath-testing devices:
- Type A devices: These are used at traffic stops or police stations to determine BAC on-site.
- Type B devices: These are used for laboratory analysis to confirm initial findings.
The Intoxilyzer 8000 is the most used Type A device in Pennsylvania. While widely accepted, its accuracy depends heavily on proper maintenance and operation.
DUI Test Calibration & Accuracy
To ensure accurate results, Pennsylvania law mandates regular accuracy inspections and calibrations for breathalyzers:
- Accuracy Tests: These tests are conducted every 30 days. They involve five simulated readings using a solution that yields a BAC of 0.10. The device must be removed from service if any results fall outside the acceptable range (0.09 to 0.109).
- Calibration Tests: Performed annually, calibration involves using solutions yield BAC levels of 0.05, 0.10, and above 0.10. These tests ensure the device provides consistent readings across various alcohol concentrations.
All testing results and certifications must be provided during pre-trial discovery. Defense attorneys can challenge expired solutions or discrepancies in these records, which may cast doubt on the reliability of the evidence.
What Leads to Inaccurate DUI Tests?
DUI tests aren’t perfect, and several factors can lead to unreliable results. These inaccuracies often stem from external conditions, personal health, or mistakes in administering the tests.
Environmental Factors
Your surroundings can have a surprising impact on breathalyzer results.
- Mouthwash or Breath Fresheners: If you used a product with alcohol, like mouthwash, just before the test, it could lead to a falsely high BAC reading.
- Chemical Fumes: Were you recently exposed to paint, glue, or cleaning products? These can also interfere with test accuracy.
- Weather Conditions: Extreme heat or cold can affect how the device works, making the results less reliable.
Biological Variables
Everyone’s body reacts to alcohol differently, and some conditions can confuse breathalyzer devices.
- Health Issues: Acid reflux or GERD can push alcohol from your stomach into your mouth, skewing results. Similarly, people with diabetes might produce ketones, which mimic alcohol in the test.
- Individual Differences: Age, weight, gender, and even how quickly you metabolize alcohol can all affect your BAC reading.
Procedural Errors
Sometimes, the problem isn’t the environment or your body—it’s how the test was handled.
- Improper Training: In Pennsylvania, officers must complete 30 hours of training to use breathalyzers. If they don’t follow the rules, the results may be invalid.
- Expired Solutions: Breathalyzers use calibration solutions to ensure accuracy, but if those are expired, the device may give false readings.
- Missed Maintenance: Devices must be tested and calibrated regularly. Without this, their accuracy cannot be trusted.
When it comes to DUI tests, mistakes, and inaccuracies happen more often than you’d think. An experienced attorney like Michael Fienman knows how to uncover and use these issues to challenge the evidence against you.
Why Are Field Sobriety Tests Often Inaccurate?
Field sobriety tests are often used to determine whether a driver is impaired. These tests typically include walking a straight line, standing on one leg, or following an object with your eyes. The goal is to evaluate balance, coordination, and cognitive function, but the results are highly subjective.
Several factors can affect your performance on these tests, even if you haven’t had a drop of alcohol:
- Anxiety: Being pulled over can make anyone nervous, causing shaky movements or mistakes.
- Physical Conditions: Issues like physical injuries, joint pain, or poor balance can mimic signs of impairment.
- Environmental: Uneven pavement, poor lighting, or inclement weather can make tests more difficult.
Are Blood & Urine DUI Tests Better?
Blood tests are more accurate than breath tests because they directly measure BAC but are not without issues. Mishandling or improper storage can lead to contamination or fermentation, skewing results.
On the other hand, urine tests are less reliable and usually a last resort. They measure alcohol in the bladder, which may not reflect current BAC, and because they rely on alcohol excreted by the body, they don’t indicate real-time impairment. Both methods require scrutiny to ensure validity in DUI cases.
What About DUI Testing for Drugs or Marijuana?
Police test for drugged driving using a combination of methods, starting with observations of behavior and administering standard field sobriety tests. If drug use is suspected, blood or urine tests may be conducted to detect specific substances, though these tests don’t reliably measure real-time impairment. Certified Drug Recognition Experts (DREs) may also evaluate drivers for signs of drug influence using physical exams and specialized training.
For marijuana, traditional THC blood tests often fail to differentiate recent use from residual levels in frequent users, but emerging methods, like the THC to THC-COOH molar ratio, show promise in providing more precise results. These tools and tests remain subject to scrutiny as they are not yet widely adopted or foolproof.
Your Rights Regarding DUI Testing
When facing a DUI test, it’s hard to know the right move in the moment, but knowing your rights is crucial. Here’s what you should understand about refusing tests and challenging the results.
H3: What DUI Tests Can I Refuse?
In Pennsylvania, implied consent laws require drivers to submit to chemical tests (breath, blood, or urine) if lawfully arrested for DUI. Refusing these tests leads to penalties like a one-year license suspension, and, in some cases, the refusal can be used as evidence of guilt in court.
However, you can legally refuse roadside field sobriety tests and preliminary breath tests (PBT), as these are voluntary and less reliable. Refusing post-arrest chemical tests carries more significant risks but may be a strategic option in certain situations.
Read 7 Mistakes People Make After Being Arrested for Drunk Driving
How to Challenge DUI Test Accuracy
If you’ve been subjected to DUI testing, the accuracy and admissibility of those results can often be contested. First, you want to avoid self-incrimination by asserting your right to remain silent. Avoid explaining any medical conditions or recent alcohol consumption to the police, as this information could be used against you. From there, consult a DUI attorney immediately. A skilled lawyer can review the circumstances of your arrest and testing procedures to identify flaws.
How DUI Lawyers Demonstrate Inaccuracy
DUI charges often hinge on the results of tests like breathalyzers, field sobriety tests, and chemical analyses. But as you can see, these methods are far from perfect. Lawyers with in-depth experience in DUI law and testing will know how to identify errors in administering such tests.
- Was the field sobriety test conducted on uneven ground or under poor lighting? Were the instructions clear?
- Was the device calibrated and maintained according to Pennsylvania law? Did an adequately trained officer conduct the test?
- Can you provide medical records to prove a condition like GERD, diabetes, or asthma affected your BAC reading?
In addition, your attorney can cross-examine officers to uncover errors in test administration, inadequate training, or misinterpretation of results, as well as use scientific research to challenge the reliability of evidence, such as highlighting the limitations of THC tests in marijuana cases or the impact of substances like mouthwash on breathalyzer readings.
Even small inaccuracies can make a big difference. An experienced DUI lawyer can build a strong defense to protect your rights and future by uncovering errors and challenging unreliable evidence.
Read The Art of a Successful Defense – A Guide for Reductions, Dismissals & Winning in Court
The Best Way to Beast a DUI Test – Call Fienman Defense
DUI tests aren’t perfect, and with the right lawyer, they can be refuted. Attorney Michael Fienman is highly regarded for his ability to identify DUI testing errors and use them to strengthen his clients’ cases. With advanced training in DUI detection and certification in Standardized Field Sobriety Testing (SFST)—the same as law enforcement—he knows how to expose flaws in breathalyzer results, field sobriety tests, and other evidence.
Whether uncovering calibration issues, procedural mistakes, or challenging unreliable testing methods, Fienman Defense is dedicated to turning the tide in your favor.
Don’t let a flawed DUI test push you into a conviction—contact Fienman Defense today. Call (215) 839-9529 for a free DUI case evaluation.
Attorney Michael H. Fienman represents clients in criminal and traffic matters throughout Pennsylvania and New Jersey. Mr. Fienman is a zealous advocate known for relentlessly defending clients in state court, federal court, and before administrative agencies. Attorney Fienman is licensed to practice before the Supreme Court of Pennsylvania, the Supreme Court of New Jersey, the US District Court for the District of New Jersey, and the US District Court for the Eastern District of Pennsylvania.
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