Expert Witnesses In DUI Cases: Why I Use Them

Not one of my clients has told me that getting a DWI/DUI won’t really make a difference in his or her life.  In other words, having a DWI or DUI conviction on your record always matters.  From the jail-time to the license suspension to the huge financial penalties, there is at least one consequence for a DUI conviction that is going to strike a chord with someone.  That is why it is absolutely necessary to have every weapon in a DUI defense arsenal available in order to attack a prosecutor’s case.  Expert witnesses are very often the best weapons to have in that arsenal.

There are many types of expert witnesses that are essential in a DWI case.  These are some of the areas where a defense witness can attack the prosecution’s case:

• Field sobriety testing;
• Breath testing;
• Blood testing;
• Urine testing;
• Drug recognition evaluations;
• Fatigue/Jet-lag issues; and
• Medical issues.

Field Sobriety Testing Experts

Although I’ve taken multiple training courses for standardized field sobriety tests (SFSTs), have read the studies concerning these tests and have actually administered them to drunk people, I don’t believe for a second that field sobriety tests actually measure a person’s sobriety.  However, prosecutors will try to use the results of these tests to convict people.  In order to combat this prosecution tactic, I will use former police officers and state troopers who trained fellow police officers to use these tests.  These defense experts will be able to attack the way the tests were administered, the way the tests were scored, and if the driver had certain physical issues that would have affected the outcome of the tests.

In addition, if a person suffers from back injury, knee injury or any other physical condition that affects balance, then a treating medical physician will be able to explain how those physical problems prevented a driver from doing balance tests.  A treating doctor’s testimony goes a long way when disputing sobriety tests.

Breath Testing Experts

Some of the issues that arise during breath testing concern the following physical conditions and these types of experts who can address those conditions:

• Diabetic attacks -> Medical Doctor or Toxicologist;
• Gastroesophageal reflux disease (GERD) -> Medical Doctor or Toxicologist;
• Limited lung capacity-> Pulmonologist;
• Exposure to volatile organic chemicals (VOCs) -> Medical Doctor or Toxicologist;
• Presence of dentures/bridges, tongue ring, tobacco -> Dentist or former breath test operator (police officers)

Other areas of attack concern the way the breath test machine was operated or if it malfunctioned at the time of testing.  Former breath machine operators or scientists in the breath testing field will be able to examine the testing procedures and the raw data from the breath machine in order to call into question the test results.

Blood and Urine Testing Experts

Many of the issues that can arise for blood/urine testing require expert testimony in the following areas with the following experts:

• Mishandling of the blood or urine specimen-> Forensic Chemist or Toxicologist;
• Chain of custody issues-> Forensic Chemist or Toxicologist;
• Failures to follow proper scientific testing procedures -> Forensic Chemist or Toxicologist;
• Contamination during testing-> Forensic Chemist or Toxicologist;
• Improper interpretation of testing data-> Forensic Chemist or Toxicologist;
• Incorrect opinion rendered concerning the effects of prescription or non-prescription drugs on ability to operate a motor vehicle-> Pharmacologist or Medical doctor.

Drug Recognition Evaluation Experts

“Drug Recognition Evaluations” have been referred to as “junk” or “voodoo” science by a vast number of reputable scientists and medical experts.  The drug recognition evaluation (dre) is used by the prosecution in an attempt to show that the driver was under the influence of a drug while operating a vehicle.  The drug recognition evaluations are done by police officers, not medical professionals.  Nonetheless, the evaluation utilizes medical procedures in order to come to a conclusion about intoxication.  These evaluations can be attacked by challenging the scientific reliability through experts in pharmacology and/or medical doctors.  Otherwise, former police officers who were drug recognition evaluators can criticize the way a drug recognition evaluation was performed by a police officer; thus, calling into question the validity of the evaluator’s opinion.

Fatigue/Jet-lag Experts – Other Medical Conditions

Fatigue caused by lack of sleep, bad sleep or jet-lag can cause people to behave in ways that mimic intoxication.  A police officer is not trained to distinguish the differences between sleep-deprived behavior and intoxication.  Medical experts can evaluate a person’s sleeping history and behavior during a DWI investigation to determine if sleep deprivation was the major cause for erratic behavior.

Likewise, people experiencing hypoglycemic or diabetic attacks will exhibit bizarre, drunk-like behaviors.   Medical doctors and pharmacologists can examine medical histories in order to determine if these medical conditions caused a person to appear intoxicated.

As the cliché goes, the best defense is a good offense.  This especially applies if you have been charged with a DUI and want to win this battle.