Challenging Field Sobriety Tests in North Carolina

When a police officer pulls over a driver on the suspicion of DWI, field sobriety tests are often used. Though these tests may determine whether a driver is under the influence, field sobriety tests and their usage are not without controversy. The important thing to remember: they are not infallible and they can be successfully challenged.

If you have been arrested for a DWI in North Carolina because you failed a field sobriety test, be sure to contact an experienced DWI lawyer. At Caulder & Valentine Law Firm, PLLC, we know the laws, we understand the technical and scientific aspects of field sobriety tests and chemical tests, and we know how to challenge them. It takes skill, resources, and insight. At Caulder & Valentine Law Firm, PLLC, we deliver quality counsel and legal representation at a time when you are worried about your future

Field Sobriety Tests: Standardized v. Non-Standardized

As a driver accused of DWI, it is important to know what comprises field sobriety tests. Field sobriety tests are part of the examination process to determine whether a driver is under the influence. It is an essential part of what a police officer does to consider arrest for DWI.

Police officers use two types of field sobriety tests to consider arrest for DWI: the Standardized Field Sobriety Test and the Non-Standardized Field Sobriety Test. Generally speaking, non-standardized field sobriety tests cannot be used in North Carolina to formulate the officer's opinion that the motorist is impaired. These test, nonetheless, are still used by the police.

Standardized Field Sobriety Tests (SFST)

Approved by the National Highway Traffic Safety Administration (NHTSA), the SFST consist of three individual tests used to evaluate whether there is probable cause to arrest a driver for drunk driving.

  1. Horizontal Gaze Nystagmus Test (HGN). Horizontal gaze nystagmus tests consist of a police officer holding their finger in front of your eye, tracking to see if there are delays to determine whether a driver is under the influence.
  2. One-leg Stand Test (OSL). A one-leg stand test is an assessment to establish a driver's balance and his or her ability to follow instructions.
  3. Walk-and-Turn Test. A walk-and-turn test determines a driver's balance and ability to stop him or herself and turn upon command from the police officer.

There are two primary concerns regarding these tests: (1) they are highly subjective, and (2) they are not fully reliable.

Subjective. Each test requires the officer to observe a certain number of clues -- like not balancing, starting too soon, hopping -- that indicate you may be under the influence of alcohol or drugs. But these clues when performed can be the result of other factors -- like weather, time of day/night, car lights, physical condition or disability, mental state -- and not due to intoxication.

Unreliable. According to original research conducted by the Southern California Research Institute, these tests can often be unreliable. In fact, the ability for these tests to detect blood alcohol content levels at or above 0.10% leaves room for error: the HGN test is only 77% accurate, the OSL is only 65% accurate, and the Walk-and-Turn is only 68% accurate.

Non-Standardized Field Sobriety Tests

Police officers also use non-standardized field sobriety tests to determine whether a driver is under the influence. This form of testing is not as common as the SFST, and more importantly, the three individual tests are not approved by the NHSTA. Some non-standardized FSTs include:

  1. ABC Test. The officer makes you recite the alphabet.
  2. Finger-to-nose Test. The officer makes you place your finger on your nose.
  3. Numbers Test. The officer makes you count to a certain number and then makes you count backward.

If you are asked by an officer to perform one of these non-standardized tests, then you should know an experienced lawyer can move the court to find these results admissible.

Flawed Performance of Field Sobriety Tests

An officer should always ask the driver if there are any known conditions that would impact the way the driver performs during a field sobriety test. But there are two problems with this: (1) the officer does not always ask; and (2) the driver may be unaware of a condition.

Poor performance often occurs for reasons unrelated to driving under the influence. This type of misinterpretation centers around the driver and his or her physical and mental health. On several occasions, medical emergencies and medicines prescribed by a doctor to treat conditions have been incorrectly categorized as alcohol intoxication.

Some of the medical conditions that affect performance and which are often the result of a mistaken DWI are:

  1. Diabetes (diabetic ketoacidosis)
  2. Drowsiness
  3. Hyperglycemia (high blood sugar)
  4. Hypoglycemia (low blood sugar)
  5. Red or watery eyes (maybe due to allergies, exhaustion, etc.)
  6. General sickness
  7. Knee injury, back injury, or other medical/physical impairment.

Flawed Administration of Field Sobriety Tests

To request a driver to submit to SFST, there must be reasonable suspicion that the driver is intoxicated. If there is no reasonable suspicion -- like the smell of alcohol in the car or red eyes -- then there is no cause for further investigation. When there is reasonable suspicion, the officer can request the driver to submit to SFST.

A driver in North Carolina, however, can refuse to submit to SFST, and an officer cannot for the driver to take the tests. At the same time, you should know that the officer can use your refusal in court as evidence of a guilty conscience.

If you do take the SFST, and most of you will, the officer must administer these tests in strict compliance with proper procedures and protocol. An experienced attorney will review videotapes and recordings and will be able to identify areas will the officer failed to administer the tests properly.

When Field Sobriety Tests are Flawed...

As a driver accused of DWI, there are options available to you worth considering and worth pursuing. If you are charged with a DWI and you question the accuracy of the field sobriety test results, then it is important to contact a North Carolina DWI attorney who can review the evidence and properly challenge the results. Shelby, NC attorneys at Caulder & Valentine Law Firm, PLLC are experienced and have helped many drivers who have been in your situation. Contact us today for an assessment of your case.


Shelby Office
303 W Marion St
Shelby, NC 28150
704.754.8401 (fax)
Gastonia Office
316 S Chester St
Gastonia, NC 28052
704.754.8401 (fax)