Standardized Field Sobriety Tests
Santa Barbara DUI Defense Lawyer
Field sobriety tests were created to give law enforcement officers an objective standard to determine whether or not a motorist is intoxicated. There are three basic sobriety tests: Horizontal Gaze Nystagmus (HGN) testing, the Walk and Turn test, and the One-Leg Stand. Combined, these tests are 91% accurate. In other words, law enforcement officers were able to determine accurately whether or not an individual's blood alcohol concentration (BAC) was higher than the legal limit (.08%) about 91% of the time. Individually, each test is significantly precise:
- Horizontal Gaze Nystagmus: 88%
- Walk and Turn: 79%
- One-Leg Stand: 83%
These statistics indicate that field sobriety tests provide inaccurate results about 9% of the time. This means that field sobriety testing can lead to wrongful arrests and unjust DUI convictions. That's why our team of Santa Barbara DUI defense lawyers is dedicated to helping drivers stand up for their rights in court. If you failed a field sobriety test and were arrested for drunk driving, you probably feel like your case is hopeless. In reality, field sobriety testing is not absolute. Even when the tests are administered correctly, they can mislead law enforcement officers to make false arrests.
The HGN test: How does it work?
The term "horizontal gaze nystagmus" refers to an involuntary jerking eye movement that occurs when the eyeball is rotated to the most extreme peripheral. Typically, this movement only occurs when you look to the side. However, a high BAC might cause the movement to occur at other times. The HGN test is performed by slowly moving a small flashlight or pen in front of the subject's eyes and moving it back and forth. During the test, the officer looks for three indicators of impairment:
- Can the subject's eyes follow the object smoothly?
- Does the eye begin to jerk when the eye looks to the side?
- Does the eye jerk within 45 degrees of the eyeball center?
If the officer identifies four of these clues between the subject's eyes, the subject may be arrested for drunk driving. However, alcohol impairment isn't the only factor that can cause your eyes to move involuntarily. Contact lenses, fatigue, seizure medications, inner ear disturbances, certain medications, and pathological disorders can cause the involuntary movement at random times. According to the National Highway Traffic Safety Administration (NHTSA), a well-trained law enforcement officer should be able to determine whether or not the nystagmus is caused by alcohol impairment or another factor.
Is the HGN test admissible in court?
The NHTSA reports several factors that may affect the admissibility of the HGN test. For example, the prosecution can submit the test as scientific or a simply observation of the defendant's physical traits. Under certain circumstances, the HGN test may not be considered reliable scientific evidence. Additionally, the test may be disregarded in court if it wasn't administered properly. For example, an improperly trained law enforcement officer could easily administer the test incorrectly. If any of these factors are not in place, the test results may be ignored in court.
Divided Attention Tests: The Walk and Turn
The Walk and Turn and the One-Leg Stand are considered "divided attention" tests. During the test, the subject is asked to complete a simple task while listening to instructions from a law enforcement officer. Generally speaking, these tests are easy to complete when you are sober and difficult to execute effectively while you are drunk. The Walk and Turn test involves nine steps. First, the subject is instructed to place his/her left foot on a designated starting line (with the right heel against the left toe). Then the officer tells the subject to complete nine heel-to-toe steps, turn, and complete nine more steps back to the starting line. The subject must count each step out loud. During the test, the officer will look for the following signs of impairment:
- Unable to balance
- Staring early
- Stopping during the test
- Stepping off of the line
- Using arms to balance
- Turning improperly
- Taking the wrong number of steps
The One-Leg Stand
Like the Walk and Turn, the One-Leg Stand involves a set of instructions and a simple task. During the test, the law enforcement officer will tell the subject to stand with his/her feet together. Then, the officer will instruct the subject to raise on leg approximately six inches off the ground and begin counting out loud until instructed to do otherwise. During the test, the officer will look for the following clues: swaying back and forth, balancing with arms, hopping to maintain balance, place foot on the ground to maintain balance. If the subject exhibits two or more of the following signs, he/she may be arrested for driving under the influence.