Pennsylvanian residents who are suspected of driving under the influence will usually undergo a process in which the officer attempts to determine if an arrest is warranted. One of the first steps in this process is the field sobriety test.
FieldSobrietyTests.org focuses on the three standardized field sobriety tests. These are used most often because they are more reliable in court than non-standardized field sobriety tests, which cannot be held to a set standard. They include the one-leg stand, the walk-and-turn, and the horizontal gaze nystagmus tests. The first test checks a person's balance and ability to stand on one leg. The second tests their ability to turn without losing their balance. The third checks the eyes for unusual movement such as shaking.
These tests are usually a precursor to a breathalyzer test or a blood test. If an officer observes a field sobriety test and believes there is still the possibility that the driver is under the influence, they will likely move on to that as the next stage of testing.
FindLaw states that evidence from field sobriety tests is frequently used in court. However, the purpose isn't to prove that the driver was under the influence. Its primary purpose is to show that the arresting officer had probable cause that the driver was under the influence in order to make the arrest.
Field sobriety tests are a crucial part of the process of being charged with a DUI. Understanding how they fit into the overall picture can help anyone preparing to face their case in court.