Authorities look for signs of intoxication before deciding whether or not to bring someone to the station on suspicion of driving under the influence. Sometimes an officer only needs to smell alcohol or see an open container in the vehicle to make an arrest. Other times, an arresting officer may conduct a field sobriety test.
Drivers may be asked to walk a straight line or stand on one leg while counting. Others may have to follow an object back and forth while the officer examines their eye movement. These tests can prove useful for the arresting officer but there are many errors that can be made during the execution of these tests and those errors sometimes lead to wrongful charges.
One of the inherent problems with field sobriety tests in California and throughout the U.S. is that they do not take into account the fact that some people cannot pass them even when sober. Some medical conditions may cause a person to fail the horizontal gaze nystagmus test even if they haven’t been drinking.