The officer will then ask you perform field sobriety tests (SFSTs). These are dual-attention tests designed to observe your responses as to whether you can listen to directions, are coordinated enough to perform the tests, and can understand what the officer is saying to you. These tests include a horizontal gaze nystagmus test (HGN). During this test, the driver is asked to follow a pen or stimulus to check of nystagmus horizontally and vertically.
Next, you will be asked to perform the walk and turn test. This is an extremely specific test that the officer will demonstrate for you. It is so specific in the steps you must take, the direction you must turn and what foot you must start with that even sober drivers can and have failed this test. Next the driver will be asked to stand on one leg and count as high as they can. The officer is looking to see how long you can stand on one leg, whether you use your arms for balance and how many times you put your foot down. Understand that these tests are not fool proof and an officer must administer these tests in an exact way to be considered reliable in court.