Field Sobriety Tests are the best method through which a police officer can establish a reasonable cause to demonstrate whether or not a driver is drunk. The results of the tests give the officer probable cause under which they can arrest the person and charge them with DUI. The outcome of an FST can be very valuable to a defense or prosecution in a court of law for their case.
In a court of law, the FSTs can be used by the prosecution to further incriminate a suspect and give them a lesser chance of defense. For a subject who was arrested on a DUI charged and failed most if not all of the standardized/non-standardized field tests, there is little to try to defend oneself against. The judges are clear on the physical and mental concentration that these tests have imposed on the individual at the time of them being administered. If the driver fails most or all of them, they have little to go on in their defense case unless they are impaired by a mental or physical condition. If the driver failed only one or two parts of the test, the prosecution will try to argue in the importance and significance of that specific test as well as the officer’s report on the subject.
The best weapon for the prosecution is the Standardized Field Sobriety Tests, where the best weapon for the defense are the Non-Standardized Field Sobriety Tests in addition to the SFTSTs. The defense can provide a much stronger argument if the person charged was told to engage in non-standardized tests. THe SFTSTs serve as a universal standard for law enforcement agencies, therefore the tests can be challenged less in a court of law for their accuracy. The NSFTSTs vary greatly amongst departments, and because of their individuality can be argued in favor of the defense if they are used to charge or further incriminate a person. These tests can vary greatly depending on which one the specific department or officer chose to administer, and their professional judgment can be argued and invalidated. However, this is not the only area where the defense can present a case to argue validity.
For example people over a certain age or weight may not be able to perform certain standardized tests due to their physical capabilities. This can cause them to fail the tests while they are completely sober, and be wrongfully accused and arrested. This can also pertain to a person with perhaps a recent surgery, or leg problem, such as joint weakness. Another case is presented for people with special conditions due to a medical issue such as a stroke, multiple sclerosis, or vision loss. Drivers can also be subject to impairment if they are given sedatives by a doctor, this can also cause the officer to believe they are drunk.
The contributions that Field Sobriety Tests can make in a case are of high importance to both sides. The results they have can have serious implications on a case, and are counted on as a reliable source of information to be presented in a case.