Every driver who is pulled over by law enforcement in California knows they are under suspicion of DUI when the officer begins the field sobriety test. The test is a basic investigation tool that all officers are trained in performing, and many of the processes are very similar. There is a variety of procedures an officer may ask of a suspected drunk driver when conducting a field sobriety test, all of which are intended to produce specific reactions that police can then use as reasonable suspicion in advancing to an investigation for probable cause.
The eye test
One of the first attributes an officer will want to check is redness and responsiveness of the eyes. Red eyes are typically a sure sign of some type of impaired state, which can be from controlled substances other than alcohol. DUI charges can be filed against those who are using marijuana or barbiturates as well as alcohol impairment.
The walking test
The second phase of a field sobriety test is typically the walking test. Suspects are instructed to walk heel-to-toe for 10 steps and then directed to turn around and perform the same walk to the point of origin. This can be a difficult test even for those who are not impaired, and many times it can end a test for DUI when the suspect completes it successfully.
Standing on one leg
There is also a test that requires standing on one leg for an extended period of time. This practice too can be problematic for some suspects, and especially those who are disabled to any degree in the lower extremities. However, officers often do not attempt to discuss disability when giving evidence in court. Suspect disability is typically introduced into the testimony by criminal defense attorneys looking to build an argument to charge validity.
These are the primary types of procedures officers conduct in any field sobriety test, and there can be some others like touching the nose with one finger. The real truth about convicting a defendant for DUI is the actual blood-alcohol concentration reading with 0.08% necessary for presumed impairment.