It is a sight New York drivers probably dread seeing in their rear-view mirror: flashing red and blue lights. Police can either conduct random traffic stops or pull over a driver based on a suspicion that the driver is impaired or drunk while driving. When this happens, the officer usually conducts a three-part field sobriety test to observe the driver's balance, attention level and physical activity.
In the horizontal gaze nystagmus test, officers are trying to see if the suspected drunk driver can follow a moving object smoothly, if the eye jerks when it is at its maximum deviation and if the eye jerks when it is 45 degrees from the center. Eye jerking is exaggerated when someone is impaired by alcohol, which is what the officers are looking for. The walk and turn test is the officer's attempt to see if the driver can complete tasks with undivided attention. The suspected drunk driver is asked to take nine steps along a straight line and then turn back and return in the same way.
Lastly, the suspected drunk driver is asked to stand on one foot a certain level above the ground and count for a total of 30 seconds. If the driver uses arms to balance, sways while balancing or hops, it could be considered signs of impairment.
The officer's record of the field sobriety test's results is noted down and can be used in a drunk driving case. The tests are also often upheld on appeal. However, is it important to note that these tests are accurate only about 91% of the time. There can be other explanations for someone's impairment, such as medication. A DUI defense could challenge the sobriety test results.