If you are stopped by the California Highway Patrol (CHP) under suspicion of driving under the influence (DUI), you may be asked to perform a series of field sobriety tests (FSTs). These tests help officers assess whether a driver is impaired by alcohol or drugs. While these tests are not foolproof, they play a crucial role in DUI investigations along with the blood or breath tests.
1. Horizontal Gaze Nystagmus (HGN) Test
The HGN test measures involuntary jerking of the eyes, which can become more pronounced when intoxicated. During this test, an officer will:
- Hold a pen, flashlight, or finger about 12-15 inches from the driver’s face.
- Move it side to side while instructing the driver to follow it with their eyes.
- Observe signs of impairment, such as inability to smoothly track the object or excessive eye jerking before reaching a 45-degree angle.
2. Walk-and-Turn Test
This divided attention test evaluates a person’s ability to follow instructions and maintain balance. The officer will instruct the driver to:
- Take nine heel-to-toe steps in a straight line.
- Turn on one foot and return with nine more heel-to-toe steps.
- Keep their arms at their sides and focus on the task.
Signs of impairment include starting before instructions are complete, losing balance, taking the wrong number of steps, or failing to walk heel-to-toe.
3. One-Leg Stand Test
This test measures balance and coordination. The driver must:
- Stand with one foot approximately six inches off the ground.
- Keep both arms at their sides.
- Count aloud (e.g., “one thousand one, one thousand two”) until told to stop.
Indicators of intoxication include swaying, hopping, putting the foot down, or using arms for balance.
4. Romberg Balance Test
Though not part of the National Standardized Field Sobriety Tests (SFSTs), the CHP sometimes uses this test to check for signs of impairment. It involves:
- Standing straight with feet together.
- Tilting the head back slightly.
- Closing the eyes and estimating the passage of 30 seconds.
Signs of impairment include excessive swaying, opening the eyes too soon, or misjudging the time significantly.
5. Finger-to-Nose Test
This test assesses motor skills and coordination. The officer instructs the driver to:
- Extend both arms out to the sides.
- Close their eyes and touch their nose with the tip of their index finger as directed (e.g., “right hand, left hand”).
Mistakes such as missing the nose, using the wrong hand, or losing balance may indicate impairment.
Are These Tests Mandatory?
Field sobriety tests in California are voluntary, meaning drivers can refuse to take them without automatic penalties. However, if an officer has probable cause for a DUI arrest, the driver may be required to take a breathalyzer or blood test under California’s implied consent law.
Conclusion
While FSTs help officers determine impairment, they are not always accurate. The Officer does not have a base line of performance without alcohol or drugs to compare results. Factors like age, medical conditions, fatigue, nervousness, or poor coordination can affect results. If you are arrested for DUI, consulting a DUI Defense attorney can help you understand what you are facing in the Court and with DMV by reviewing your case, educating you on what happens now and helping you get the best resolution possible in your case.
