It is the duty of all police officers to protect and serve. If one notices you driving erratically, he or she may pull you over on suspicion of driving under the influence. In order to determine this, however, the police have a limited number of options.

One of the most common ways an officer may attempt to show you are intoxicated is by administering a field sobriety test. These tests aim to provide evidence of alcohol consumption by examining the way you respond to a variety of tasks that are perceived to be simple. If you are unable to perform a test adequately, the officer may use this information as probable cause to make an arrest.

The goal of removing a threat to your safety from the road is admirable, but can you truly trust the results of a field sobriety test? This certainly seems like a fair question considering how much a DUI conviction can negatively impact your personal life.

Examining the statistics

Police officers around the country have used field sobriety tests for many years. To determine the validity of these tests, the Southern California Research Institute evaluated a handful of examinations to find out which were the most accurate.

Police officers were brought in and asked to evaluate how well people performed these tests. Their objective was to decide whether each subject had a blood alcohol concentration of .10% or higher. After collecting the results, the SCRI recommended that the police use three tests to conclude that a person is legally intoxicated:

  • Horizontal gaze nystagmus
  • Walk and turn
  • One-leg stand

These three tests were determined to have the highest rate of accuracy. However, the truth is that they can still provide inaccurate results due to a variety of issues. When all three tests are used in conjunction, the results are accurate 82% of the time, according to the study.

Individually, the horizontal gaze nystagmus was most successful at determining impairment at 77%. The walk and turn test finished second with an accuracy rate of 68%. This was followed closely by the one-leg stand at 65%.

There is little doubt that field sobriety tests can be useful when attempting to determine if a person is legally intoxicated. However, scientific research has concluded that they are not consistently reliable and are an imperfect measure for charging someone with a DUI.