In most cases, police officers aren't allowed to randomly or arbitrarily pull drivers over, but instead must justify traffic stops. In cases where a traffic stop results in a suspected drunk driving arrest, proper procedures must be followed.
Field sobriety tests are a series of tests designed to help a police officer determine whether or not a driver is impaired by alcohol or drugs. Sobriety tests that are frequently administered include the horizontal gaze nystagmus, walk-and-turn and one-leg stand. Additionally, a police officer may also request that an individual submit to a Breathalyzer test or provide a blood or urine sample.
When conducting field sobriety tests, police officers must follow strict procedures. Failure to do so can result in mistakes and inaccurate test results and readings. Additionally, in cases where a police officer believes that an individual is guilty of driving under the influence or operating while intoxicated, again certain procedures must be followed when placing an individual under arrest and processing evidence.
With heavy workloads and hectic schedules, some police officers are bound to make mistakes. A breathalyzer machine may not be correctly calibrated, an officer may fail to inform an individual of his or her Fifth Amendment rights or a crime lab may err when analyzing a blood sample.
Individuals in Michigan who are facing DUI or OWI charges would be wise to contact a defense attorney. DUI and OWI cases are not always clear-cut or open-and-shut cases. A criminal defense attorney who handles drunk and drugged driving related matters will work to refute evidence and vigorously defend an individual's rights.
Source: FindLaw.com, "Field Sobriety Tests," 2014