Field Sobriety Tests in DUI Cases

Each year, in the state of California, over 200,000 people are pulled over and subsequently arrested for driving under the influence. Driving under the influence is defined as operating a motor vehicle with a blood alcohol content of .08 or higher, or, for those under the age of 21, driving with a blood alcohol content of .02 or greater. Most DUI arrests start with a police stop for driving patterns indicative of intoxication, traffic violations, or pre-arranged alcohol checkpoints. For many accused of drunk driving the initial stop will begin with a field sobriety test. Field sobriety tests and their validity have been called into question regularly by those stopped for drunk driving, and, many times, the results of such tests are not admissible in court. Regardless of their validity they are still regularly administered.

History of the Field Sobriety Test
Field sobriety testing has been around for as long as laws against driving under the influence have been on the books. The first drunk driving law, for example, was instituted in New York in 1910. California soon followed, and the laws simply prohibited anyone from driving while intoxicated with no set limit, although the generally accepted limit was .15, nearly twice the current legal limit. By 1970s laws were greatly enhanced and altered to better crack down on drunk driving, but one problem remained, a lack of standardized testing. In 1975 The National Highway Traffic Safety Administration (NHTSA) asked the Southern California Research Institute to study the 16 field sobriety tests that were used the most often by police officers on suspected DUI stops. The goal of the study was to find the most reliable tests. Of the 16 tests available, three were chosen to be standardized. The institute found that the Horizontal Gaze Nystagmus Test, the One-leg Stand and the Walk-the-line tests were the most accurate. These three tests become the standardized field sobriety test that most people are familiar with. While these three tests are the standard there are alternative tests that are used.

Three Standardized Tests
The Standardized Field Sobriety Test, also known as the SFST, consists of three test administered and evaluated officer administering the tests. The officer's evaluation is to follow strict guidelines, however, there is room for interpetation in some of the tests. The standardized tests are considered to offer valid indicators of impairment and are often used as probable cause for a DUI arrest. The three tests include the Horizontal Gaze Nystagmus, the walk-and-turn, and the one-leg stand.

Horizontal Gaze Nystagmus, known as HGN testing, is a test that looks for involuntary movement of the eyeball. When not impaired the eyeball will move to a side gaze when tracking an object at an extreme angle. Tracking an object, while not impaired, is a smooth transition. While impaired the eyeball will gaze sideways at much less extreme angles, and the impaired person will have a difficult time tracking an object smooth. A “jerking” effect of the eyeball can be seen in most cases when a person is impaired. HGN testing looks for three distinct indicators of impairment. First it looks for jerking while following an object at maximum deviation. The test also tests for jerking within 45 degrees of the center of the eyeball that is 45 degrees from the normal position of the iris. Finally, it looks for how smoothly the eye follows. If these clues appear there is probable cause to assume the BAC level of the person is about .10, or greater than the legal limit of .08 for driving.

The walk-and-turn test is considered a divided attention test. The subject is asked to take nine steps, heel—to-toe, along a straight line, then they are asked to turn on one foot and repeat the same nine steps in the other direction. This is all done along a straight line, often the highway shoulder line, or other road indicators. The officer will look for several indicators of impairment while this task is being performed. The officer will look to see if the subject can keep their balance while listening to the instructions, if they begin before the instructions are complete, if they stop during the act to regain balance, whether or not they use their arms to gain balance, whether or not they can complete the turn in a fluid motion, and whether the instructions were followed correctly. According to research by the NHTSA 68% of people who fail two or more indicators of sobriety on the test will register a .10 or greater BAC reading.

The final standardized test is the one-leg stand. This test is also considered a divided attention test. The test requires the subject to stand on one foot with the other foot about 6 inches off the ground. The subject is then instructed to count by thousands to 30. An officer administering this type of test will look for a subject who has difficulty keeping their balance in the form of swaying. He or she will also look at whether the subject is counting correctly, and whether or not they are hopping or using their arms in an attempt to maintain their balance. According to the NHTSA 65% of people who fail two or more indicators of the one-leg stand test will register a BAC of .10 or higher.

While these three tests are considered to be the most standard field sobriety tests there are several other alternative methods that can be used as indicators of intoxication. In the state of California there are seven tests, including the standardized field sobriety tests that can be used by officers who suspect a driver is driving under the influence. Often times these alternative tests are used when a suspect is disabled or physically impaired to the point where they are incapable of performing the standardized tests, either sober or intoxicated.

Additional Field Sobriety Tests Used
While police will often use the three standardized field sobriety tests listed above there are alternate tests available. These alternate tests can be used when a person has a physical impairment that would make the standardized tests difficult to complete even while sober. The alternate options can also be used at the officer’s discretion, or alternate tests can be requested by the subject. These tests take into account medical hardships that make the standardized tests void. For example, a middle ear problem can make balancing difficult without alcohol impairment. Being overweight, or having bone or joint issues can make balancing on one leg an impossibility. The standardized tests take into account only the physically healthy, thus alternate tests have been created for these situations.

The Romberg balance test is often used for those who can’t, for physical reasons, balance on one leg. The test requires the subject to stand with their feet together and head tilted slightly back. The eyes are closed and the subject is asked to remain in the position for 30 seconds, or what they believe to be 30 seconds. When they believe the 30 seconds have elapsed they are to tilt their head forward open their eyes and say “stop”. The test looks for the person’s ability to keep their balance, any swaying that takes place, their ability to estimate 30 seconds, and their ability to follow the directions given to them.

The finger to nose test is also used in many states. This test asks the subject to touch their nose using the tip of their index finger, alternating from the left hand to the right hand. The head should be slightly tilted back and the subjects eyes are to be closed during the test. The subject is asked to follow the “left” or “right” directives given by the officer. This test looks for the person’s ability to follow instructions, as well as the amount the person sways with his or her eyes closed. The test also measures the subject’s depth perception while completing the task. This test can be considered a divided attention test.

The finger count test, while uncommon because there is no scientific research on it, can be employed in certain situations, as well. This test requires the subject to count using their fingers, starting with their index finger, by touching each finger to their thumb. The subject is also instructed to count as they do it. The officer will also instruct the subject to do the same thing backwards, starting with the pinky finger, while counting backwards as well. Three sets are to be done per hand. This test attempts to measure the person’s ability to follow instructions, and to keep track of their counting while performing a physical act. While there is no scientific evidence that the inability to complete the test is indicative of intoxication, it is still utilized.

Finally, an officer can ask a subject to complete the alphabet test, if they are incapable of completing a physical task due to mobility issues. The alphabet tests requires the subject to say the alphabet out loud. Some officers will also ask for it to be repeated backwards. This test simply looks to see if the subject can follow directions. It also checks for slurring of the speech, and the subjects ability, or inability, to complete a simply task. Once again, there is little scientific evidence to back up this method of field sobriety testing.

After Field Sobriety Tests
Field sobriety tests are a flawed system and most lawyers would advise the general public to decline taking such tests. If you have, however taken the test and failed, you’re evening is nowhere near over. Field sobriety tests are a way to bolster the officer’s case. The goal of the field sobriety test, for the police officer, is to find a failure and to arrest them for driving under the influence. If the subject fails a field sobriety test they will often be asked to take a Breathalyzer test. The Breathalyzer measures the alcohol content on the breath, which is then estimated into a blood alcohol content. The BAC is what is used to decipher whether a person is driving under the influence or not. The legal limit for the United States is .08, which is equivalent to about 3 servings of alcohol for the average size person. A small person, weighing about 100lbs, likely can only have a single serving of alcohol while remaining under the legal limit. This is important to remember, as a subject may not feel drunk, or may not believe they drank enough to be impaired, when in actuality they are.
After failing a field sobriety test and a Breathalyzer test the subject is arrested and taken to the station. There they are given a summons and may be held until another person can come and pick them up. Most DUI cases do not require bail, and rather, the person is released on their own recognizance. The summons will have a court date that the defendant must appear at with their lawyer. This first date is considered the arraignment. The arraignment allows for the defendant to plead guilty or not guilty. After the arraignment subsequent court dates will be set up.

Results Used Against the Defendant
The results of a field sobriety test can be used against the defendant in the court hearing leading up to a trial as well as at a trial. The results can be used by the prosecution to show probable cause for the arrest, as well as evidence of the impairment. In some cases, a defense lawyer can argue that the evidence is faulty for a number of reasons and should be stricken from the record. A defense lawyer can argue that the officer’s results were wrong, that conditions were bad for the tests, or that the defendant has an underlying condition that would make the results invalid. These arguments are normally heard prior to going to trial, or during the plea bargaining phase, following the arraignment.

If the evidence is permitted by the judge, then the prosecution will use any and all field sobriety failures as evidence of the defendant’s intoxication. Video, recordings and the police officer’s notes are submitted to the court and shown to the jury. The jury can then use the information to convict the defendant of the crime of driving under the influence.

Even if he case never makes it to trail field sobriety results can also be used in pre-trial hearings. If the evidence is considered permissible a judge can use the information when considering plea bargains. For example, the use of field sobriety test evidence can mean the difference between an alcohol-related violation, and charges being dropped to a non-alcohol related driving infraction.

The Odds of Passing a Field Sobriety Test
Many people wonder what the odds of passing a field sobriety test are. Well, there is no hard scientific evidence regarding this, however, it is known that there is a 38% false arrest rate that means 38% of people who submit to the testing fail, even though they are not impaired at the time. With that being said, there is evidence that many people can pass a field sobriety test when sober. In fact, about 75% of people can pass all standardized tests while sober, but nervousness, physical impairments, ear and eye problems, and weight issues can all factor into false failures. Because of this many suggest refusing the test in favor of blood tests or Breathalyzer tests. The reasons are simple, these tests actually measure the alcohol content in the blood. There is nothing subjective about a blood test or a Breathalyzer, while human error can play significantly into the results of a field sobriety test.

While the odds of passing aren’t in a defendants favor due to human factors, and individual who does pass a field sobriety test is in better shape than a person who fails or refuses to take it. When one refuses to take the test they are treated much like a person who has failed. The subject is arrested and booked for suspicion of DUI and given a court date, just as if they had failed the test. A person who passes a field sobriety test is often sent on their way and not brought in on suspicion of the crime, although this is not a guarantee either.

Reliability and Protocol
While field sobriety tests tend to be the first step of a DUI arrest a driver is in no way legally obligated to submit to any field sobriety test. In fact, studies have found that the results of field sobriety tests are often unreliable at best, and many people have difficult time passing the battery of tests when perfectly sober.
The Southern California Research Institute found, in the 1980s, that there are significant problems with the standardized field sobriety test. Further testing found that people with leg, back or middle ear problems would have a difficult time completing the walk-the-line test as well as the one-leg stand test while sober. The institute also found that people overweight by 50 pounds or more would also have difficulty completing the task. Uneven ground, wet conditions, and officer error also make the tests unreliable. In fact, the institute suggests that there might be a police failure rate as high as 47% and the use of field sobriety tests have a 38% false arrest rate.

So, how does someone pulled over for a DUI decline a field sobriety test? Simply by saying they would prefer not to take the test. An officer cannot force a field sobriety test on a person and they are 100% voluntarily. Because of their lack of reliability, many times field sobriety test results are thrown out as evidence in court. However, a defendant who chooses to take one, may find that their results are being used in court, and it can make it more difficult to garner a good plea bargain deal. Most lawyers will insist that taking the field sobriety test very rarely helps a suspects cause, and, actually, can be damaging to their case, regardless of whether or not they were driving while impaired.