Florida DUI Expert Witnesses

A lawyer rehearsing her defense arguments to represent a client in court.

Most DUI cases involve scientific testing of some kind.  When you perform field sobriety exercises, a breath, blood, or urine test, there are scientific principles at work.  Although Florida law does not allow field sobriety exercises to be considered scientific, many states do allow these tests to be called scientifically proven or validated.

Is Field Sobriety Testing Reliable?

Most DUI arrests involve the officer asking or telling the driver to perform roadside tests to help them determine the driver’s impairment.  In Florida these are called Field Sobriety Exercises (FSEs).  Throughout most of the rest of the country they are referred to as Standardized Field Sobriety Tests (SFSTs).  In many states experts battle about the scientific reliability of these roadside agility maneuvers, however in Florida, our courts have determined that these roadside tricks do not have scientific value.  The state may not refer to them as “tests,” and testimony cannot be elicited regarding whether the driver “passed or failed” these exercises.  However, at times an expert on the performance of these exercises may be used.  

Drug Recognition Experts (DREs)

This is especially true when one of the investigating officers is a “Drug Recognition Expert (DRE).”  DREs are given more latitude when testifying about the field exercises, especially the Horizontal Gaze Nystagmus (HGN) exercise.  Although most police officers cannot testify about the tracking of a subject’s eyes during the HGN, DREs can.  Often judges will even allow DREs to testify to a blood alcohol level based on the DREs interpretation of HGN test data.  

The expert DUI attorneys at Katz & Phillips, P.A. have all had training in combating DRE testimony. In truth, out of the thousands of DUI cases David Katz has handled, he has only seen the HGN exercise performed correctly, according to the officer’s training on 2 occasions.  Common areas in which the officers make errors when performing the HGN exercise are:

  • Holding the stimulus (usually a pen or light) too high.  It is supposed to be slightly above the driver’s eye level.
  • Holding the stimulus to close or to far from the driver’s face.  It is supposed to be 12-15 inches away.
  • Moving the stimulus to rapidly across the driver’s field of vision.  This is supposed to take 4 seconds from one side to the other, however, most officers take 2 seconds or less.  Moving the stimulus to quickly can cause nystagmus invalidating the test.
  • Not properly estimating a 45-degree angle for angle of onset.
  • Holding the stimulus too long at maximum deviation.

These are just the most common errors observed.  The point is that when a scientific test is performed any deviation from the standardized instructions invalidates the test.  The Expert DUI attorneys at Katz & Phillips, P.A. know how the tests are required to be administered correctly and do not need an expert witness to review the roadside videos to see what was done wrong.  However, if the errors affect the outcome of the tests, we have several Field Sobriety Exercise Experts that we have worked with, available to testify and help in your case if needed. 

In fact, each of the field sobriety exercises has a set of instructions which the officers are trained to follow.  When they do not follow them, our attorneys instantly know.  We also know how to use these errors to your advantage.  The standard battery of field sobriety exercises includes the HGN (discussed previously), the Walk & Turn (W&T) and the One Leg Stand (OLS).  Additionally, there are other frequently used exercises including the Rhomberg Alphabet (also called the Rhomberg with recitation), the Rhomberg Balance, the Finger to Nose, and the finger touch.  Additionally, the Coast Guard has a battery of at sea or on the water tests they use in Boating under the Influence cases.

Breath Testing

In Florida there is currently only one approved breath test machine.  It is called the Intoxilyzer 8000 and is manufactured by CMI, Inc. out of Kentucky.  The Intoxilyzer 8000 uses infrared light waves at specific wavelengths to determine the alcohol content of your breath.  This law firm has been involved in many complex legal battles involving the Intoxilyzer 8000 which has resulted in the suppression of tens of thousands of breath tests in Orange, Seminole, and Lake Counties Florida.  We may be able to keep the breath test results out of evidence in your case too.  Contact the Expert DUI attorneys at Katz & Phillips, P.A. today to discuss your breath test results.

In Orange, Seminole, and Lake counties we held multiple day hearings bringing in experts in many fields including lung physiology, computer engineering and software design, laboratory auditing and scientific standards, pharmacology, computer data analysis, and more and in each case, for various reasons, breath tests were suppressed.  Of course, the facts of each case vary, and past results do not mean that future cases will have the same results.  Your results may vary.  The point is that at Katz & Phillips, P.A., our expert attorneys have actually been to court and fought the battles over the admissibility of the breath test in Florida.  Most other attorneys either joined in the hearings we argued or tell their clients that there is nothing that can be done because they took the breath test and plea the clients guilty to the DUI charge.  Most DUI attorneys do not fight the admissibility of the breath test unless something goes wrong with their client’s particular test.  We are experienced at fighting the admission of breath test results based on the flawed scientific principles of breath testing itself, the assumptions made by the breath test machine about human physiology, and many other areas.

Blood Testing

Blood Testing using a dual column gas Chromatogram is considered the gold standard of scientifically reliable and accurate testing.  This may be true on properly maintained and operated machines, but the crime labs that do the testing in DUI cases are run by the government using government employees.  The saying close enough for government work is not close enough for us.  If your DUI case involves a blood test, we will hold the State to the proper scientific testing standards.  We have worked with experts from the U.S. and Canada on blood test DUI cases.  Our Expert DUI attorneys know what to look for and have specific training in fighting DUI blood cases.  We also know the very few times an officer is allowed to request or require a blood sample in Florida.

Unlike many states, the state of Florida has limited the cases in which a blood test may be required of a DUI suspected driver.  A law enforcement officer can only require a blood test if the DUI suspected driver is in an accident which results in death or serious bodily injury.  Further, under Florida’s implied consent law, a blood test can be requested of a driver who is suspected of DUI, was in a crash, and is in a medical facility for treatment.  However, in order to request a blood test in that case, a breath or urine test must be impossible or impractical.

In blood cases, the chain of custody of the blood sample as well as proper storage from the moment of the blood draw to and through testing is of utmost importance.  Further, proper procedures for drawing the sample, and the type of blood tube used for the blood draw make a huge difference.  After the blood is drawn, the person drawing the blood must invert the blood tube a specific number of times in a specific manner or the sample can be compromised.  Many times, those used to drawing blood for medical purposes do not know or follow the procedures for proper legal blood draws.  The expert DUI attorneys at Katz & Phillips, P.A. know the right way to do it, and will make sure that proper procedures were followed in your case at every turn.  

Further, medical blood draws for medical purposes are tested in different ways than legal blood.  Even though medical blood testing can overstate the alcohol content of the blood by up to 300% and are meant only as a screening tool, the Florida Supreme Court has said that medical blood test results are admissible to prove alcohol content.  Therefore, it is imperative that an expert witness be used to explain the unreliability of medical blood tests in DUI cases.  At Katz & Phillips, P.A. we work with respected and highly skilled experts to help explain to a jury what the state’s blood test results really mean and why they cannot be relied upon.

Urine Testing

Urine tests are the least used tests for impairment cases in Florida.  Under Florida law urine can only be requested when a law enforcement officer has probable cause to believe the person they arrested for DUI is under the influence of a chemical or controlled substance.  Further, if law enforcement originally believed that a person was impaired by alcohol and the person then blew a lower breath alcohol level than the law enforcement officer expected that does not automatically give them a right to then request a urine sample.  Many cases have had the urine results suppressed because the officer only asked for a urine test after not getting the breath result they expected. When urine tests are administered legally, there is still much that can be done to challenge the results.  Urine tests are the least strictly controlled alcohol tests in the state of Florida.  In fact, the Florida Department of Law Enforcement has no standard procedures that must be followed when administering or testing urine, which can lead to non-scientifically reliable processes and procedures being used.  

Get Expert Florida Legal Advice from Katz & Phillips, Orlando

At Katz & Phillips, P.A. we work with a team of laboratory analysts, quality control analysts, and scientific experts that can be used, when necessary, on your case to help discredit the “scientific evidence” offered by the state.  Call the Expert DUI attorneys at Katz & Phillips, P.A. to discuss the facts of your case and see how our team approach can benefit you.


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