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Field Sobriety Testing


Any New York resident who drives regularly may be curious about how police test drivers to determine whether they are driving under the influence. There are three tests recommended by the National Highway Traffic Safety Administration, which measure the driver’s responses to stimulus and ability to follow instructions. Each test is intended to be something that a sober person could pass.

The first test used to check for drunk driving is the horizontal gaze nystagmus test. This test looks at the angles that the driver’s eyes move. It also measures the driver’s ability to focus on a moving object, such as following the officer’s finger as it is moved back and forth.

The next two tests both measure whether the driver is capable of following specific instructions while moving. The officer may direct the driver to walk heel-to-toe for nine steps. He might also ask the driver to stand on one foot while counting aloud for up to 30 seconds. The officer is checking to see if the driver listens to all instructions before beginning the task, follows the instructions given or loses balance during the test. Swaying, losing balance, failing to count out loud, taking the wrong number of steps and hopping are examples of ways a person might fail one of these tests.

When a person is accused of drunk driving, a local criminal defense attorney might review the evidence in order to come up with the best possible defense. In some cases, an attorney may be able to challenge the field sobriety test results. It may also be possible for an attorney to seek to negotiate a reduction in the charges or less jail time in exchange for a guilty plea.

Source:, “APPENDIX A: Standardized Field Sobriety Testing”

Source:, “Standardized Field Sobriety Testing”, November 22, 2014