Breathalyzer and Field Sobriety Tests


Ensuring police follow procedures during DWI traffic stops

The tests police give to suspected impaired drivers provide considerable evidence for prosecutors at trial, but the criminal defense attorneys at Clifford & Harris, PLLC have learned through experience that the tests also help build a strong defense.

Police use standardized field sobriety tests (SFSTs) to assess a driver’s impairment and to establish probable cause to conduct a confirmation blood or breath test. The SFST is merely an indicator of alcohol (or drug) consumption, but it can be the basis of a DWI arrest. However, only an Intox EC/IR II (generally referred to as a Breathalyzer) breath test or blood or urine testing can confirm alcohol content — the accuracy of those tests is also the subject of a vigorous scrutiny.

Types of SFSTs

Because DWI penalties are so severe, our lawyers deconstruct these DWI tests, seeking deficiencies in the test, the equipment and how the investigating officer was trained or conducted it. Standardized SFSTs include:

  • “Eye bounce” or horizontal gaze nystagmus (HGN) test — Excessive alcohol consumption can cause a disturbance in the inner ear, which results in loss of control of the eye muscles and makes the eye jerk. Sometimes called bouncing of the eye, it also can be caused by consumption of other substances. The more impaired you are, the more the eye will jerk or bounce. A National Highway Transportation Safety Administration (NHTSA) study in 1998 found that the HGN, when conducted correctly by police, allows proper classification of approximately 88 percent of impaired-driving suspects.
  • Walk and turn test — In this DWI test, you are asked to walk a straight line. If there is faltering movement or hesitation in your walk, or any other sign of impairment, then you fail the test. The NHTSA study found 79 percent of individuals who exhibit two or more indicators in the test will have a blood alcohol content of 0.08 or greater.
  • The one-leg stand test — You are asked to stand on one leg. If you can successfully do so, you pass. You may be asked to stand on alternate legs. The NHTSA research found 83 percent of individuals who exhibit two or more indicators will have a blood alcohol content (BAC) of 0.08 or greater.

When the component tests are combined, officers are accurate in 91 percent of cases, the study showed.

Other non-standardized tests you may encounter include:

  • Alcosensor handheld breath test administered in the field and not admissible in court
  • Finger to nose with eyes closed
  • Recite all or part of the alphabet
  • Count backward
  • Stand with your feet together and tilt your head back, which can also be done with the arms out
  • Count the number of fingers raised by the officer
  • The hand pat test, which is done by extending both hands out in front, one hand with the palm up and the other with the palm down, then alternating the patting of each palm with eyes closed

Your Right to Refuse

You can legally refuse any of these tests. Prosecutors likely will use your refusal against you in court, but there is no other penalty.

However, once you are taken to the station, you must carefully consider the consequences if you choose to refuse to take the Intoxilyzer breath test. If you refuse that test, your driver’s license will automatically be suspended for one year under North Carolina law. You do, however, have the right to call a witness to the breath test, as long as he or she arrives within 30 minutes (timing of the test is critical for accuracy). Your best bet is to call a lawyer, even if you are a repeat DWI offender and you think you know the system.

Attorneys Who Know How to Fight DWI Tests

At Clifford & Harris, PLLC, we pursue every possible challenge in ensuring you receive fair treatment in the judicial system. If you have been arrested for drunk driving, do not hesitate to contact us. We are at your side to the end, with the caliber of representation you deserve. Call our firm at 336-574-2788 or email us for a free consultation today.