I had a family member serve on a felony DWI jury. The charge was DWI with a minor in the car. Two days of trial and a guilty verdict.
I wanted to know what mattered to the jury and how the juror saw the tests. Here are some observations from my relative (who shall remain nameless).
1. The jurors had trouble understanding the HGN test. However, they did assume that the HGN was valid. The idea being that the police would only use a test that was valid. Too bad the science behind HGN has never been peer reviewed or subject to double blind studies. Also, the HGN has a failure rate as high as 38%.
2. It is important to attack the procedure of field tests as well as the science/results.
3. Jurors who were also mothers leaned strongly towards conviction from the beggining (the case was DWI with a minor passenger). They expressed anger over someone driving after drinking with a child in the car.
4. Some jurors will perform the field sobriety tests while deliberating. They will then compare their results to the defendants.
5. Jurors discount testimony from the defendant’s relatives.
6. Performing bad on a field sobriety test is worse than choosing not to perform.