Sobriety Field Tests: Designed for Failure: Just Say No.
Roadside agility tests were designed for failure. As a practical matter, if the Officer asks you to take these tests he has already decided to arrest you. You will not be able to prove your innocence by doing these silly rigged tests. The eye test or HGN test looks for rapid eye movement or nystagmus which can be caused by many things other than a blood alcohol level of .08 or more. The Walk and Turn is too physically demanding for many people and most officers do not give the correct instructions. The One Leg Stand is also just too hard for most people; moreover, the officers will often pick areas that are not level making the test even more impossible.