Cop car at night

How do police use balance tests in DWI investigations?

By Jose Ceja
Managing Attorney

If you have been arrested for DWI, the police probably administered police balance tests known as Standardized Field Sobriety Tests as a part of the DWI investigation.  These tests are used across the country as a standard part of DWI investigations. Law enforcement in the Houston area receive a DWI training course and certification to administer these balance tests. But what do the tests mean and how reliable are they in detecting that a DWI suspect is intoxicated? 

If you are stopped or detained by a police officer, and the officer suspects you might have been driving while intoxicated, the police officer will typically ask you to perform police balance tests. There are three “standardized” tests that are a part of DWI investigations in the United States (meaning that they should be administered in the same way). In most DWI investigations, officers do not give a person the option to refuse and will instruct a driver to submit to the taking of tests. Despite what a police officer may say, a suspect in a DWI investigation has a right to refuse to participate in police balance tests (although that may cause an officer to arrest the suspect). 

The first of the tests DWI officers usually administer is called the horizontal gaze nystagmus test. This is sometimes referred to as the “follow the pen” test. This test is supposed to detect an involuntary jerking of a person’s eyes that shows that a person has consumed a central nervous depressant, like alcohol. This test is the most difficult for law enforcement to administer correctly since it attempts to detect three types of jerking (an experienced DWI attorney can actually get this test thrown out of court if it is not administered correctly). Most DWI attorneys believe that this test is also the least significant as a typical juror does not put much stock into whether a police officer claims a person passed of failed this test. 

The next test that DWI officers typically administer is knows as the walk-and-turn test. This is sometimes referred to as the “walk the line” test. For this test an officer asks a DWI suspect to place one foot on a real or imaginary line and hold that position. Then the officer explains the test, which involves a series of heel-to-toe steps, a turn, and a return to the starting position. Although this test is a balance test, it is also used to test a DWI suspect’s ability to multi-task and perform the test in the exact way that is requested. 

For the walk-and-turn test, a DWI officer is trained to evaluate a suspect’s performance by looking at whether 8 instructions are not complied with, like whether a suspect steps off the line, misses a heel-to-toe step, stops while walking, or turns improperly. If a DWI suspect gets two or more instructions wrong, then he is considered to have failed the test (according the research, a DWI suspect who gets two or more instructions wrong likely has a blood alcohol content of greater than 0.08).

Most DWI attorneys would agree that this test is virtually impossible for a person to pass, particularly on the side of the road, where a person is nervous and scared that he or she might go to jail. When DWI attorneys evaluate a suspect’s performance on the walk-and-turn, how a person looks – whether they stumble or have obviously bad balance, for example – is much more important than how a person scored on the test. 

The final test that is a part of DWI investigations is called the one-leg stand test. For this test, a suspect is asked to put one foot in the air and hold it there for 30 second, while keeping his arms at his sides. DWI officers look for 4 signs of intoxication. This test is also very hard for many people to perform successfully whether they are intoxicated or not. 

Of course, the point of these DWI tests is to establish whether a person is intoxicated. In Texas, prosecutors can prove that a person is intoxicated by showing that the person lost the “normal use of their mental or physical faculties.” In a DWI trial, prosecutors will argue that a suspect’s performance on the DWI tests, as well as any other evidence of a suspect’s driving, statements, or appearance, are evidence of a loss of “normal use” of mental or physical faculties.

It is the job of the DWI attorney to challenge the eye test and police balance tests by challenging their admissibility, reliability and whether there were reasons why a particular suspect could not perform them as instructed (a pre-existing injury, for example). Experienced DWI attorneys should be intimately familiar with the proper administration of these tests and the limitations of the research. An experienced DWI attorney should also be certified to administer the tests. 

Attorney Jose Ceja is a former prosecutor and experienced DWI attorney who has successfully handled hundreds of DWIs throughout the Greater Houston area. He has obtained “not guilty” verdicts in DWI trials and is certified to administer police balance tests. If you are charged with DWI anywhere in the Greater Houston area, call Ceja Law Firm today for a free consultation. 

About the Author
Jose Ceja is the managing attorney of Ceja Law Firm. He has practiced law since 2007 and has devoted his career to the practice of criminal law. Mr. Ceja began his legal career as a felony drug prosecutor, where he prosecuted drug, gang, and violent offenses. Mr. Ceja has first or second chaired almost 100 trials, including murders, drug cases, DWIs, and assaults. In his career as a defense attorney, he has regularly obtained dismissals, not guilty verdicts, and grand jury “no bills” in a wide variety of cases.
Posted in DWI