If the police officer claims that you have “failed” one or more field sobriety tests then your attorney may attempt to raise a reasonable doubt about the value of the test or the conclusion of the officer. Your attorney will do this in several ways, including these general tactics:
The prosecutor is then likely to respond to these attacks in one or more of the following ways:
Assuming that the field sobriety tests were given pursuant protocols established by the National Highway Traffic Safety Administration (NHTSA), the prosecutor is likely to emphasize the research that went into developing the field sobriety tests.
The prosecutor will make the tests seem as scientific as possible to heighten their perceived accuracy.
The prosecutor will probably emphasize whatever special training that the officer received about field sobriety testing.
The prosecutor will make sure that the jury knows that the officer did not just receive training at the police academy, but also that the officer was trained in the field. The prosecutor may also point out the officer’s own personal experience over the years. The officer’s personal investigations may total in the hundreds or even thousands of DUI investigations.
Assuming that the officer gave the instructions for the test correctly, the prosecutor is likely to point out to the jury that the officer explained the instructions to you carefully and accurately. The prosecutor may also point out that the officer demonstrated the tests to you, so that you had ample opportunity to understand the tests.
The prosecutor may have an expert who has done correlation studies comparing field sobriety tests with blood alcohol levels. If the performance on the field sobriety tests correlates to what is expected for a person with your blood alcohol level then the prosecutor will probably have the expert emphasize this consistency to the jury.
If either you or some of your friends testify about how you did on the field sobriety tests then the prosecutor will probably ask whether you or your friends have any specialized training in administering field sobriety tests. The answer will almost always be no.
The prosecutor will then argue that the jury should believe a trained officer rather than someone who has never administered field sobriety tests.