As in all states, New York police base their decision to stop someone for driving under the influence of alcohol on two principal observations: the motion of the car in traffic; and behavior of the driver. Once the police suspect the motorist is drinking and driving, they can further verify their suspicions by having the motorist perform field sobriety tests. These tests are typically administered roadside although they may also be administered at the police precinct. The three tests commonly used in New York state include:
The One Leg Test. A police officer will ask the driver to stand on one leg while holding the opposite foot about six inches off the ground and ask the driver to count for 20-30 seconds. The police officer is looking to see how well the motorist maintains his balance and follows instructions. Any swaying, hopping, putting your foot down or trying to hold on for anything will cause the driver to fail the test. The One Leg Test measures balance while your mental attention is focused on something else. The best way to perform a One Leg Test is to listen to the police officer’s instructions carefully, remain as still as possible and focus on a distant object while counting aloud.
The Horizontal Gaze Nystagmus Test. A police office will ask a suspect to watch either a pen or their finger while their vision is monitored. During this test, the police officer is looking to see if the eyes are trembling or jerking. This test lets the police track the movement of the motorist’s eyes. There is no "best way" to perform this test because the police are looking for involuntary movements that the motorist cannot keep under control.
The Walk and Turn Test. The police officer will ask the motorist to walk a certain number of steps in a line then turn around and walk the same amount of steps back. The Walk and Turn Test measures the accuracy of someone’s balance. The best way to perform this test is to start walking upon the police officer’s direction, not step out of line, not lose track on how many steps you took and not put space between your heel and toe. Starting to walk too soon, falling out of line and losing count of your steps are indications that the driver is drunk.
Breathalyzer. Of course, the police will also seek to administer a breathalyzer test. This test determines the motorist's blood alcohol concentration (BAC) level and a motorist can be charged with a misdemeanor or felony solely depending on their blood alcohol level. The best way to minimize your blood alcohol content level is not to operate a motor vehicle immediately after drinking. It is best to wait a significant amount of time before driving to let the alcohol leave your body.
The results of field sobriety tests will be used by the prosecution in their case against the driver. However, these results are exchanged with the motorist’s defense attorney in the discovery portion of the case. A defense attorney can then challenge the results of field sobriety tests and how the police officer administered them as part of their client's defense.