Kurtz & Blum, PLLC - Criminal Justice Attorney

The Use Of Field Sobriety Tests In DWI Cases

If a police officer stops you and suspects that you are driving while impaired, they may ask you to perform field sobriety tests. Police officers use field sobriety tests, or FSTs, to find signs of impairment and to establish probable cause with which they can arrest you for DWI. It is important that you understand your rights related to these field sobriety tests. You can also contact the dedicated DUI defense lawyers at Kurtz & Blum for immediate assistance.

What Is a Sobriety Test?

Law enforcement officers who suspect a driver is drunk test the driver for signs of impairment so that they have probable cause to make an arrest. The law enforcement officer may administer one or more of these sobriety tests that consist of tasks that would be difficult for a drunk driver to complete. Then, the officer may use an instrument to measure the suspect’s blood alcohol concentration (BAC). The goal is to obtain enough evidence sufficient to establish probable cause for a DWI arrest.

Types of Field Sobriety Tests

Police often use “standardized” field sobriety tests, or roadside tests, when testing for alcohol intoxication. The National Highway Transportation and Safety Administration (NHTSA) has established three standardized sobriety tests, which it claims are scientifically proven to help establish alcohol impairment. However, it is important for people to understand that these tests are designed to find that they are impaired, not to prove them innocent. The goal is to use field sobriety tests to establish probable cause to make an arrest for DWI.

There are three standardized field sobriety tests, as well as other tests some police officers might use.

Horizontal Gaze Nystagmus (HGN) Test

The first test officers might use is the horizontal gaze nystagmus test, or HGN test. In this test, the law enforcement officer will have you track the movement of a pen or finger with your eyes. Nystagmus is an involuntary jerking of the eye, which occurs naturally when you look to peripheral stimuli. Scientific studies show that nystagmus becomes more pronounced in the event of impairment. Here, the officer is looking for six signs (three in each eye) that indicate impairment:

  • Lack of smooth pursuit where eyes jerk as they focus on tracking movement
  • Distinct and sustained nystagmus at maximum deviation (jerking where the eyes are stretched all the way to the side)
  • Onset of nystagmus occurring prior to reaching a 45-degree angle

Four of the six potential signs indicate a BAC above the legal limit and can give rise to probable cause for the officer to arrest you for DWI. However, even if you display four or more signs, there are a number of methods that experienced criminal defense lawyers can use to attack the results and challenge the HGN test. Certain medical conditions and legal substances, like caffeine or aspirin, can affect a suspect’s ability to perform this test well. Additionally, the officer must be properly trained and administer the test with correct timing and movement, or the test results will lack scientific validity.

Walk-and-Turn Test

The next test officers may administer is the Walk and Turn test, or WAT test. This test requires you to follow instructions while performing simple physical movements. In the Walk-and-Turn field sobriety test, the officer instructs you to take nine steps. These are heel to toe steps that you must walk in a straight line. The officer is supposed to provide you an actual line for guidance – though many will ignore the standard procedure and ask you to walk an imaginary line. After the ninth step, you will have to turn, per the officer’s instructions, and retake the steps back toward your original starting point. The officer is looking for eight clues, only two of which are needed to indicate impairment and a BAC above the legal limit for purposes of DWI:

  • Inability to maintain balance while listening to the instructions
  • Beginning before the instructions are finished
  • Stopping while walking to regain balance
  • Failing to touch heel-to-toe
  • Stepping off the line
  • Using arms to balance
  • Making an improper turn
  • Taking an incorrect number of steps

One-Leg-Stand Test 

In the one leg stand test, or OLS test, you must stand with one foot about six inches off the ground while counting aloud until you are told to put your foot down. An officer will look for four clues, two of which are needed to indicate a BAC above the legal limit:

  • Swaying while balancing
  • Using arms to balance
  • Hopping to maintain balance
  • Putting the foot down

If you take the OLS test or WAT test and perform poorly, there are still ways for experienced DUI defense attorneys to attack the results. Officers must administer the tests correctly according to NHTSA guidelines and be properly trained. Medical conditions can affect a suspect’s performance, including their ability to walk or balance. Weather, location, surroundings, your weight, and even your choice of clothing can also factor into a poor performance on these tests.

Other Field Sobriety Tests

Once you have completed these standardized tests, the officer may proceed with other field sobriety tests or arrest you if they feel there is adequate probable cause for DWI. Other tests are not NHTSA approved and have not been scientifically validated, but that doesn’t stop police and courts from using them.

Other field sobriety tests that an officer may administer outside of the three standardized tests discussed above include:

  • The Romberg balance test, which requires you to hold your balance for approximately 30 seconds when standing with your feet together, head back, and eyes closed
  • Finger-to-nose test
  • Reciting parts of the alphabet
  • Finger counting by touching thumb to fingers also known as the “Finger Dexterity Test”
  • Counting backwards

If you were given any of these field sobriety tests, you should not hesitate to contact the experienced DUI defense lawyers at Kurtz & Blum for help.

Portable Breath Test

If the officer administers other sobriety tests, he or she will often ask you to take a portable breath test, or PBT. A PBT may not be used to prove guilt of impaired driving in court. It may only be used, along with other field sobriety tests, to prove that there was probable cause for arrest. If you agree to take a portable breath test, the officer will have you blow twice into the instrument with the second blow occurring a few minutes after the first.

There are ample opportunities for a criminal defense lawyer to attack the results from a PBT. The instrument must be properly documented, maintained, and calibrated. Like the other field sobriety tests, the officer must be properly trained and follow definitive guidelines.

Field Sobriety Tests and Your Legal Rights

Before a police officer can stop a motorist, they must have reasonable suspicion that they are impaired or have committed another traffic violation. Law enforcement can ask the motorist to take field sobriety tests. However, you have a right to refuse to take any field sobriety tests without consequence. This field sobriety test refusal does not represent strong evidence against you. There are many valid reasons why someone might refuse a FST, including distrust of the police. Having bad results on field sobriety tests is much more damaging than simply refusing the test. This is in stark contrast to the breath test. In such situations, you may refuse to blow into a breath test, thereby potentially limiting the officer’s power to observe you for signs of impairment, but you can still be arrested. Once you are arrested, you cannot refuse a chemical test to measure blood alcohol content without penalty. Specifically, refusal to submit to a chemical analysis of your breath results in a one-year revocation of your driver’s license. Furthermore, once probable cause has been established, police can easily secure a warrant from a magistrate to draw your blood for chemical analysis.

If you do consent to taking sobriety tests prior to being arrested for DWI, the officer will likely proceed with one or more of the standardized NHTSA field tests and may potentially administer other sobriety tests. These tests are meant to test simple physical and mental capabilities to determine if the suspect’s BAC is above the legal limit. The three standardized field sobriety tests must be administered systematically and require an officer to look for certain responses. This does not mean that they necessarily administer them correctly.

Can the Test Results Be Used in Court?

Law enforcement touts field sobriety tests as reliable at indicating alcohol impairment and a blood alcohol content above the legal limit. However, even the three standardized tests can result in errors. Officers must be trained properly and follow strict guidelines. If you perform poorly, your results can be fought and potentially suppressed. If suppressed, it can be exceedingly difficult for a prosecutor to establish that the law enforcement officer had probable cause to arrest you and everything that comes after arrest will be suppressed as well. If the arrest is suppressed, no evidence will remain from which a court can convict you of DWI. 

Contact Kurtz & Blum Today 

Our DWI lawyers are here to protect your rights if you are accused of DWI. Kurtz & Blum helps people throughout Wake County, North Carolina. We frequently handle offenses arising out of the following cities: Cary, Morrisville, Rolesville, Zebulon, Apex, Knightdale, Wendell, Fuquay-Varina, Holly Springs, Wake Forest, Garner, and Raleigh. Contact us for a confidential consultation about your drunk driving case. 

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