Texas drivers can expect to complete either a field sobriety test or a breath test when pulled over for suspicion of driving under the influence of alcohol. There is more than one type of field sobriety test, but the most common one is the Horizontal Gaze Nystagmus. The test the officer requests depends on a variety of factors.
The Texas District & County Attorney Association mentions that alcohol and brain injuries cause HGN. This makes the test a fairly reliable indicator for officers looking for the presence of alcohol in the driver’s blood. The alcohol can cause the eye to make bouncing motions or jerk.
Law enforcement officers receive training to distinguish alcohol causing HGN from other medical issues such as head trauma. Impairments both physical and mental can show up in a field sobriety test, but the HGN is not the only test used. The famous walk and turn or one-leg stand are other options used by officers.
Guardian Interlock mentions what officers look for prior to giving the driver a field sobriety test. The officer assesses the driver’s reflexes, general demeanor, eyes and breath. Slurred speech, bloodshot eyes, clumsiness and alcohol on the breath indicate to the officer the high possibility that the driver is under the influence.
In addition to the tests listed above, the officer may have the driver recite the alphabet backward, do a finger-to-nose test, balance with eyes closed or count backward. Many officers rely on their experience before asking the driver to conduct a field sobriety test, breath test or both. The results can mean the difference between heading home or riding in a squad car.