by | last updated on January 19, 2016
One common type of evidence used for drunk driving charges is the field sobriety tests, which are designed to evaluate whether a driver is intoxicated through physical or cognitive examinations.The problem with these tests is that the results are often completely based on a police officer’s perception of the driver, and not hard evidence. Because the analysis of a driver’s performance on these tests can be easily skewed, it may be challenged during a DUI charge by Fort Lauderdale criminal attorneys.

The History of Field Sobriety Tests

There are three types of standardized field sobriety tests and several more non-standardized tests. The National Highway Travel and Safety Administration (NHTSA) has developed standardized tests as well as guidelines for analysis after researching their effectiveness.

Over the years, many DUI charges have been impacted by attorneys challenging the reliability of these tests to indicate an illegal level of intoxication. A Fort Lauderdale criminal attorney may do the same in a recent DUI case as well.

Types of Standard Field Sobriety Tests

When an officer stops a driver suspected of DUI they may be asked to perform the standardized tests.

The three most common tests, which are the standardized tests from the NTHSA, are:

  • One-leg stand test The driver must stand with one foot six inches off the ground and count aloud by one-thousands (one-thousand one, one-thousand two, one-thousand three) until told to lower the foot (about 30 seconds).
  • Walk-and-turn test The driver is asked to take nine heel-to-toe steps while looking down and counting each step aloud.
  • Horizontal Gaze Nystagmus (HGN) test The officer shines a small flashlight or pen light into the driver’s eyes and moves it across the field of vision, watching the driver’s ability to track a moving object and the responsiveness of his or her eyes.

These tests are not without flaws. The first two are known as “divided attention” tests where the officer is looking to see whether or not the driver can maintain attention to physical coordination and the verbal counting task.

The HGN test is one that is based on the fact that a human eye should not jerk involuntarily (nystagmus) when looking at a stationary object within 45 degrees of the center of their eye. If the eye does jerk, it is used as a sign of intoxication; however, there are several other medical factors that may cause nystagmus when sober, which a defendant may discuss with Fort Lauderdale criminal attorneys handling the DUI charge.

Types of Non-Standard Field Sobriety Tests

There are also several non-standardized tests that may be used to gauge a driver’s intoxication.

Some of the common non-standardized tests include:

  • Rhomberg Balance Test The driver stands up straight, closes his or her eyes, tilts the head back, and holds the position for their estimation of 30 seconds.
  • Finger to nose – The driver places his/her feet together, stands straight with eyes closed, and is asked to stretch their arm out and touch the index finger to his or her nose.
  • Finger tap test – The driver is asked to hold out one hand and touch each fingertip to their thumb tip and count aloud during each tap, forward and backward, for three sets.

There are also verbal tests such as reciting the alphabet or counting backward that are designed to test a driver’s cognitive response as well as check for slurred speech. However, speech problems, coordination problems, various medical conditions and other factors may influence the results of these tests, which Fort Lauderdale criminal attorneys may challenge.

Challenge DUI Charge with the Help of Fort Lauderdale Criminal Attorneys

According to a 2005 study published in the Journal of Forensic Science by Dr. Michael P. Hlastala of the University of Washington, the accuracy of a field sobriety test is only 30-60 percent when drivers who are suspected of DUI actually have a blood alcohol concentration (BAC) tested at 0.06 – 0.08 percent. This may mean that there are thousands of “drunk drivers” wrongfully accused every year because of inaccurate tests.

Fort Lauderdale DUI Attorney Robert Malove attended the Miami-Dade Field Sobriety Testing Course in 1995, and is very experienced in cross-examining officers on this topic.  Contact Fort Lauderdale criminal attorneys to schedule a consultation regarding your rights if charged with DUI and to go over the field sobriety test evidence against you.