DUI and the HGN (“Follow With Your Eyes, Not Your Head”) Test

Imagine being asked to follow a pen with your eyes during a traffic stop. This simple request might seem harmless, but it’s actually one of law enforcement’s most powerful tools for detecting impaired drivers. The Horizontal Gaze Nystagmus (HGN) test, which boasts an impressive accuracy rate, has become a cornerstone of DUI investigations across the country.

While most people focus on breathalyzers and “walking a straight line,” it’s your eyes that might give away the most telling signs of being under the influence of alcohol. Understanding how the HGN test works, your rights regarding its administration, and its limitations could make a crucial difference in your interaction with law enforcement.

What is the Horizontal Gaze Nystagmus (HGN) Test

The Horizontal Gaze Nystagmus test (HGN) detects involuntary jerking of the eyes when a person looks to the side while holding his or her head still. Administration of the HGN test is commonly used by law enforcement officers during DUI stops to assess potential impairment.

How Police Conduct the HGN Test

Law enforcement officers follow specific procedures when conducting the HGN test during a DUI stop. They look for three specific signs: lack of smooth eye movement, distinct jerking of the eye at maximum deviation, and nystagmus occurring before 45 degrees.

The officer first positions you at a comfortable distance and explains the test instructions. Then, they check your pupils to ensure equal pupil sizes and that both the left eye and the right eye can track objects properly.

The critical instruction is to follow with your eyes only while keeping your head still. The officer moves a pen or finger horizontally across your field of vision, making several passes at eye level and watching for telltale signs of impairment.

Common mistakes occur when subjects move their head instead of just their eyes or when officers conduct the test too quickly or in poor lighting conditions.

Other Field Sobriety Tests

Law enforcement officers may combine other standardized field sobriety tests together to build a stronger DUI case. The walk-and-turn test requires subjects to take several heel-to-toe steps along a straight line, turn around, and return the same way. During the one-leg stand test, individuals must balance on one foot while counting aloud for 30 seconds.

The combination of tests helps to rule out physical limitations that might affect a single test’s results. For example, someone with a leg injury might struggle with balance tests but show clear signs during the HGN evaluation.

These tests are used to demonstrate probable cause to believe a person is intoxicated before an arrest is made.

Chemical testing through breathalyzer, blood, or urine analysis usually follows these field tests to confirm impairment levels.

Can I Refuse an HGN Test?

In Michigan, you have the legal right to refuse any field sobriety test, including the HGN test. However, refusing to cooperate won’t help avoid arrest. Officers can still take you into custody if they have probable cause to suspect impairment.

It is, of course, important for the DUI attorney to look for problems with the administration of these tests as well as the collection and testing of evidence. Any such issues should be raised by the lawyer in a formal, legal challenge to the evidence.

Here’s what many people don’t realize: once an officer asks you to step out of your vehicle for sobriety testing, an arrest is likely regardless of whether you agree to testing or how well you perform. The officer has typically already observed signs of potential impairment that led to this point.

If you refuse the HGN test, or any (or even all) of the requested field sobriety tests, the officer will almost always proceed with a DUI arrest and will request chemical testing at the station.

DUI Arrest Statistics Show Very Few “Not Guilty” Verdicts in Michigan

The numbers paint a clear picture of DUI case outcomes in Michigan. Each year, out of tens of thousands of DUI arrests in the state, less than 0.2 (yes, that’s “zero POINT two) percent of all cases go to trial and result in a “not guilty” verdict.

This means over 99.80 percent of the people arrested for a DUI in Michigan did NOT win at trial.

Police videos rarely capture eye movements during HGN testing, limiting evidence to officer reports. However, when dash cam footage shows poor performance on other sobriety tests like the walk-and-turn or one-leg stand, HGN test challenges become less effective. Slurred speech during alphabet recitation or counting exercises further supports officer observations.

While attorneys may point out potential flaws in DUI cases, the statistics show most cases don’t turn out successful by going to trial. Video evidence of physical coordination problems and speech issues often outweighs questions about HGN test administration.

How Accurate is the HGN Test in Detecting Impairment?

It is important to note that the HGN test is not used to show that a person was drunk, or how drunk they were. Instead, the HGN is used for the purpose of showing that the police officer did, in fact, have probable cause to arrest someone for drunk driving (and thereafter administer a breath test).

This means that any good DUI lawyer is still going to carefully review the whole case to make sure there was sufficient probable cause to make the traffic stop in the first place, and otherwise make sure that there is legally admissible and sound scientific evidence (meaning breath or blood test results) that a person was actually over the limit at the time they were driving. To put it another way, the HGN test can support your arrest, but a lot more is needed for a DUI conviction.

Limitations Surrounding the HGN Test

While the HGN test serves as a common field sobriety measure, it faces several notable criticisms. The test relies heavily on officer interpretation, making results subject to human error.

Other various conditions that are unrelated to alcohol may trigger nystagmus, including vertigo, multiple sclerosis, and certain prescription medications. Age-related vision problems and natural eye conditions may also produce similar eye movements.

Our defense attorneys can challenge the test results by highlighting improper administration or alternative explanations for eye movement patterns. Other defense strategies may focus on:

• The officer’s training and certification records
• Weather and lighting conditions during testing
• Documentation of proper test procedures
• Medical records showing relevant conditions
• Video evidence contradicting officer testimony

If You Have to Take an HGN Test There’s a Chance You’ll Be Arrested

Despite potential limitations of field sobriety tests, if you are standing at the side of the road and a police officer is in front of you instructing you to follow their finger, or pen, and not move your head, a DUI arrest is basically a done deal. Following that arrest, when you provide a breath or blood sample over the BAC limit, you need to really start thinking about how to make the situation better beyond just wishing it away.

Sure, everyone facing a DUI charge wants the whole thing to just “go away,” but then again, everyone would want to be a millionaire, too. Just wanting something doesn’t make it happen. In other words, by the time you’re taking an HGN test at the side of the road, there is a really good chance that you are going to be arrested for a DUI.

When to Call a DUI Defense Attorney

Timing matters when contacting a defense attorney about your DUI case. Whether you’ve just been released or received a court notification, an attorney needs to examine all evidence types:

• Body camera footage (if applicable)
• Dash cam recordings
• Police reports
• Chemical test results
• Field sobriety test documentation
• Investigation of the scene itself, if warranted

Recent cases show how video evidence can contradict officer reports. For example, an officer might claim a driver “stumbled repeatedly” during field sobriety tests, but video shows proper balance and coordination. These discrepancies can lead to case dismissals. Shortly before this article was republished, our team got a DUI case dismissed for just that reason.

Blood sample handling also requires scrutiny. Michigan DUI law affects how winter temperatures can freeze blood samples in transit – violating testing protocols. A defense attorney can use these technical issues to fight for a dismissal, or in plea negotiations, especially in borderline cases where blood alcohol levels tested just above legal limits.

At Jeffrey Randa & Associates, our attorneys will review testing procedures, evidence collection methods, and proper protocols–similar to how doctors examine test results before undertaking treatment procedures. This thorough evaluation helps build the strongest possible defense strategy for our clients.

Ready for Reliability? Contact Jeffrey Randa & Associates.

Understanding the HGN test’s role in DUI investigations empowers Michigan drivers to make informed decisions during traffic stops. While the test serves as a valuable tool for law enforcement, it’s essential to remember that various factors can affect its accuracy, from medical conditions to environmental circumstances.

Don’t let HGN test results determine your future. If you have been arrested for a DUI in the Greater Detroit area, contact Jeffrey Randa & Associates to see how our legal team can help. Our law firm’s track record shows we know how to protect your rights and challenge field sobriety evidence effectively. Call our firm today for a free consultation at 586-496-7014 or 248-600-5013 or fill out our online contact form.