Challenging Your DUI Test Results

Attorney Oberhauser Studies The Science. He’s The Only Certified ACS-CHAL Forensic Lawyer-Scientist In Massachusetts!

OUI Field Sobriety Tests

When making an OUI arrest, an officer must first have reasonable suspicion to pull you over. “Reasonable suspicion” may involve weaving, driving erratically, speeding, or violating a traffic law.
DUI Tests in Massachusetts
If an officer believes you were driving under the influence of alcohol or drugs, you may be asked to perform a battery of field sobriety tests. These sobriety tests are intended to provide probable cause to arrest you for DUI.

The truth of the matter is that in Massachusetts, in all likelihood you will be arrested and asked to take a formal breathalyzer or OUI blood test if you:

  1. Perform poorly or fail the field sobriety tests, or
  2. Refuse to take the FSTs.

The breathalyzer tests in Massachusetts have come into question within the last few years. More information about the breathalyzer being ruled inadmissible.

If the officer observed “impaired driving cues” or stopped you for a traffic violation but then smelled alcohol, it will be exceedingly difficult if not impossible to test your way out of an OUI arrest, because police are trained to err on the side of caution when it comes to public safety.

But there are several ways Attorney Oberhauser can have the OUI charges against you dropped and dismissed all together—even if the evidence against you seems solid:

  • If an officer doesn’t have reasonable suspicion to pull you over
  • If the field sobriety test was improperly administered
  • If the officer wasn’t certified to administer the test
  • If you were administered a breathalyzer. They were ruled inadmissible and not allowed as evidence at trial.
  • If you were not read your Miranda Rights before interrogation.
At Oberhauser Law, we’ve successfully represented countless people arrested for drunk driving. Too often, however, people make the mistake of assuming that they cannot fight the charges. They believe that because an officer pulled them over, made them walk a straight line and then blow into a breathalyzer, the evidence against them must be air-tight. WRONG!

Remember that you are innocent until proven guilty in a court of law. The state has this burden of proof and it must prove its case beyond a reasonable doubt. An arrest and test does not prove guilt!

Before you plead guilty to a charge, contact criminal defense attorney Gregory Oberhauser for a free consultation. He may be able to challenge your DUI test results.

Field Sobriety Tests – How Do They Work?

Police departments use the National Highway Traffic Safety Administration’s DWI Detection and Standardized Field Sobriety Testing Student Manual when administering field sobriety tests. The way field sobriety tests work comes directly from the manual itself, which painstakingly details where and how to give the tests.

There are 3 field sobriety tests that have been standardized (“validated”) according to the NHTSA:

  1. Horizontal Gaze Nystagmus (HGN -the eye test)
  2. Walk and Turn
  3. One-leg Stand

Nystagmus is involuntary eye jerking at peripheral angles and only occurs when something is interfering with your central nervous system -presumably alcohol. But many things can cause nystagmus, including flashing lights, head injuries, medications and illness.

In fact, dozens of conditions unrelated to alcohol consumption could impact all DUI road tests. Furthermore, there is no conclusive evidence that a person who is sober will perform better on an FST than a person who is intoxicated. 

The Walk and Turn and One-leg Stand are basically roadside Olympics. In one famous seminar, judges were given these tests and failed them.

No research has determined how long on average a person should be able to stand steady on one leg.  Any correlation between impairment and these “tests” should be treated with the highest level of skepticism.

Greg Oberhauser is trained in the NHTSA FSTs and knows where most evaluators make mistakes. He demonstrates these errors in court to defend his clients and win their DUI cases.

How accurate are Field Sobriety Tests?

NHTSA says these tests are “easy and simple” for someone who is sober to perform. In reality, it’s been demonstrated that nearly 35% of sober individuals fail at least one of the tests and are arrested for OUI.

In addition, officers don’t always follow the detailed procedures of the manual. Failing to follow all protocols results in “failures” based on false-positive clues. Furthermore, with the possible exception of the eye test, performance evaluation is entirely subjective.

NHTSA strongly recommends officers perform the eye test first. Why? Because HGN is the only sobriety field test that can lay any real claim to being scientifically backed. Even so, HGN got it wrong when adjusted for the legal BAC limit of .08 in 76% of NHTSA’s own test subjects.

Unfortunately, during a DUI investigation the officer is both judge and jury. That is why you need attorney Gregory Oberhauser. He will identify where officers departed from sobriety testing standards as per their own training manual.

He will question the officer’s administration of the tests and cast doubt on the conclusions drawn in establishing probable cause for your arrest. Often, the strongest FST defense is illustrating for the jury the pseudoscience of the tests and how they unfairly set the driver up to fail.

DUI Test: The Breathalyzer

Take note that the breathalyzer was ruled inadmissible and not allowed as evidence at trial.

URGENT UPDATE:  This decision affects thousands of defendants that pled their OUI in Massachusetts between June 2012 and September 14, 2015. If you were convicted of an OUI and failed a breathalyzer test during this time frame contact our office IMMEDIATELY for a review of your case.


Cases in point: the Draeger Alcotest 9510 breath test machine used by MA law enforcement. Attorney Gregory Oberhauser worked on the legal team that challenged the machine’s reliability. Result: Thousands of OUI cases thrown out!

How to Challenge the Breath Test

breathalyzer testsBreathalyzers must be properly maintained and calibrated. Driving under the influence of alcohol laws in Massachusetts require over 20 specific methods and procedures for breath test certification.

If even one of these is not adhered to, a breath test result can be challenged so that it won’t be admitted into evidence.

Our OUI defense service includes reviewing the maintenance schedule of the breathalyzer to check if it issued any false-positives in the past. We also look for any certification and compliance problems pertaining to your result.

BrAC Biochemical Challenges

Even when calibrated in accordance with the statute, a number of forensic experts have questioned the application of Henry’s Law to the breath-alcohol content (BrAC) and partition ratio.  And rightly so.

This is a specific alcohol to blood ratio that  manufacturers use in the design and function of their breathalyzers, but it is a critical presumption. As a result, the possibility of inflated results is greater than most people realize.

In cases where a person’s blood alcohol content (BAC) is measured slightly above .08%, following proper procedures is even more important. You should have been asked to provide at least 2 samples, but each blow should have used a new mouthpiece. If not, your results may have been inflated enough to put your reading over the legal limit.

How much time passed between your DUI stop and when you gave a breath or blood sample can also add weight to your defense.  Most of these DUI defenses can be highly effective; however they’re also very technical and require the right kind of scientific training and experience to pull off.

DUI Blood Test: Blood Alcohol Content (BAC)

Blood tests typically provide a more accurate measure of BAC. Yet, the result of a blood test can also be affected by a number of factors:

blood test for dui

  • Did the nurse swab your arm with alcohol before drawing your blood?
  • Were expired vacuum tubes coated with preservative used to store your blood?
  • Did the sample collected contain mostly whole blood or serum plasma?
  • Was it a preliminary test or one that used gas chromatography (GC)?
  • What is the blood lab’s rate of error, and is it scientifically determined and reported?

If GC wasn’t used, the results are less dependable and subject to greater questioning and reasonable doubt. These are only some of the issues that could arise to call into question the results of a DUI blood test.

Urine DUI Tests

Because alcohol is evenly distributed and diluted in water, a person’s alcohol impairment is not accurately predicted by urine DUI tests. As a result, Massachusetts police officers do not normally request a urine test for OUI of alcohol cases.

However, like DUI blood tests, urine tests are sometimes used to detect the presence of alcohol and other intoxicant drugs in a suspect’s system. As with blood testing, there are several problems that can arise from testing urine, including:

  • Over-the-counter medicines can trigger false-positives from a urine drug test for DUI, as can …
  • The presence of Prescription medications.
  • Many urine tests are toxicology screening tests, meaning they are non-conclusive.
  • A tox-screen (blood or urine) must be followed up with a confirmation test analyzed for a specific substance.
  • Percent of alcohol in urine is disproportionate to % in blood (BAC).
  • The state lab can make errors of procedure and/or analysis that adversely affect urine DUI test results.

Just because a DUI test indicates that you are over the legal limit doesn’t mean it’s true. The stakes are extremely high in OUI – DUI cases. Your license, freedom and future happiness is in jeopardy. Don’t prejudge yourself or assume you will be found guilty -talk to Gregory Oberhauser instead.

Contact Lowell, Massachusetts DUI Defense Attorney Greg Oberhauser today. He can identify any pseudoscience used by the state and help you prepare a strong defense against an OUI conviction.