There are not many things that I dislike more than taxes. As a Houston DWI Lawyer I have come to dislike the horizontal gaze nystagmus (HGN) more than them. The reason I believe this is the case is because the National Highway Traffic Safety Administration (NHTSA) is lying to the public, the officers they train, and the prosecutors that use them to convict people.
The HGN is an unscientific test. The lie is first and foremost that it the most reliable of the field sobriety tests. This is untrue! How can a study that only had 28 subjects, done in a lab setting, a test that has not been peer reviewed, and took over four years to complete be reliable? The study has not been cited by anyone else for determing a person's blood alcohol content.
Moreover, the test is easily manipulated. The test may be affected by how fast the officer does the passes in front of the person's eyes, moving objects in front of a person's eye site, or flashing lights. The NTSA manual used by the police does not state the amount of jerking required to in order to measure one of the six clues in the HGN test. Therefore, the test is subjective. Lastly, every person has some sort of nystagmus, and there are over 45 forms of nystagmus that are not related to alcohol.