Failed a HGN Field Sobriety Test Illinois? Why Your Results May Be Invalid

Posted on in Criminal Law

HGN, DUI, DuPage County Criminal Defense AttorneyThe "eye test" is a common field sobriety test that is conducted by law enforcement during DUI stops in Illinois. The official name of the test is the Horizontal Gaze Nystagmus (HGN). If the officer has any suspicion that you may have been drinking, he will usually conduct an HGN test. However, the test has many different steps and specific procedures. If the test is not performed exactly as standardized, or if  the officer combines steps, omit portions of the exam or perform the test too quickly, the results may be invalid.

There are several different versions of the HGN test. These include observing your eye movement patterns with use of a stimulus held about twelve inches from your face and moving the stimulus:

  • From side to side;
  • Up and down;
  • Around the eyes; and
  • Toward the eyes.

Typically, you will be instructed to stand with both feet together and your hands at your sides. The test should begin with the officer checking the eyes for equal pupil size and equal tracking. This step can reveal medical conditions that cause Nystagmus, which is defined as rapid involuntary movements of the eyes. However, many officers skip this critical first step, thereby invalidating the results before the test has even begun.

The officer may or may not instruct you to keep your head straight and follow the movement only with your eyes. The officer will be watching your eyes and trying to see when your eyes begin to flutter. He or she will be looking for distinct patterns beyond the normal eye movement such as a lack of smooth pursuit of the eyes while following the stimulus and jerking or involuntary movements. While you are being tested the officer will be observing the following:

  • Whether or not you are swaying from side to side;
  • Whether or not your head moving from side to side; and
  • If you keeping your head straight and only following along with your eyes.

The HGN tests are often improperly administered by law enforcement and as such, their results are invalid. If you have received a DUI charge as a result of failed sobriety tests there is no time to delay. Please contact a  DuPage County DUI criminal defense attorney with over two decades of experience defending clients in the Illinois criminal justice system. At the law firm of Scott Anderson, our team is proud to defend clients against DUI charges in Cook, Lake, DuPage and McHenry Counties. Call 847-253-3400 to schedule a free initial consultation today.