What to Expect During Field Sobriety Tests

Table Of Contents

What Are Standardised Field Sobriety Tests?

Standardised Field Sobriety Tests are a battery of three specific tests officers use to assess a driver's impairment. The National Highway Traffic Safety Administration developed these tests. Officers administer the Horizontal Gaze Nystagmus (HGN) test, the Walk-and-Turn test, and the One-Leg Stand test. These tests provide officers with clues about a driver's physical and mental faculties. Officers look for specific indicators of impairment during each test.
Officers conduct Standardised Field Sobriety Tests after a traffic stop. The officer first observes the driver's behaviour. The officer then decides if there is reasonable suspicion of impairment. The officer will explain the instructions for each test. The driver must follow the instructions precisely. The officer observes the driver's performance throughout each test. The officer notes any deviations from the correct performance. The officer uses these observations to help determine probable cause for a DWI arrest.

How Does the Horizontal Gaze Nystagmus Test Work?

The Horizontal Gaze Nystagmus Test works by observing the involuntary jerking of a driver's eyes. Nystagmus is the involuntary jerking of the eye. Alcohol consumption can exaggerate this jerking. The officer instructs the driver to follow a small object with their eyes. The officer moves the object horizontally. The officer observes the driver's eyes for specific clues.
The officer looks for three clues in each eye during the Horizontal Gaze Nystagmus Test. The first clue is a lack of smooth pursuit. The eye does not follow the object smoothly. The second clue is distinct nystagmus at maximum deviation. The eye jerks noticeably when held to the side. The third clue is the onset of nystagmus prior to 45 degrees. The eye begins to jerk before reaching a 45-degree angle. Four or more clues out of six indicate impairment.

What to Expect During the Walk-and-Turn Test?

What to expect during the Walk-and-Turn Test involves performing a series of physical movements under instruction. The officer instructs the driver to take nine heel-to-toe steps along a straight line. The driver then turns on one foot. The driver then takes nine heel-to-toe steps back along the same line. The officer looks for specific clues of impairment during this test.
The officer looks for eight clues during the Walk-and-Turn Test. The first clue is the driver losing balance during the instruction phase. The second clue is starting too soon. The third clue is stopping while walking. The fourth clue is not touching heel-to-toe. The fifth clue is stepping off the line. The sixth clue is using arms for balance. The seventh clue is an improper turn. The eighth clue is taking an incorrect number of steps. Two or more clues indicate impairment.

What to Expect During the One-Leg Stand Test?

What to expect during the One-Leg Stand Test involves balancing on one foot for a specific duration. The officer instructs the driver to stand with feet together. The officer instructs the driver to raise one foot approximately six inches off the ground. The driver keeps the raised foot parallel to the ground. The driver counts aloud from one thousand one to one thousand thirty. The driver maintains this position for thirty seconds.
The officer looks for four clues during the One-Leg Stand Test. The first clue is swaying while balancing. The driver exhibits noticeable side-to-side or back-and-forth motion. The second clue is using arms for balance. The driver raises the driver's arms six or more inches from the driver's sides. The third clue is hopping. The driver lifts the stationary foot from the ground. The fourth clue is putting the foot down. The driver places the raised foot on the ground before thirty seconds expire.

Non-Standardised Field Sobriety Tests

Non-Standardised Field Sobriety Tests are other physical or mental exercises officers sometimes request a driver to perform. These tests do not have the same scientific validation as the Standardised Field Sobriety Tests. Officers might ask a driver to recite the alphabet backwards. Officers might also ask a driver to count numbers in reverse. These tests are less reliable indicators of impairment.
Officers might use Non-Standardised Field Sobriety Tests to gather additional observations. These observations can support an officer's belief of impairment. The officer's subjective interpretation plays a larger role in these tests. The scientific community does not widely accept the results of these tests. A driver's performance on these tests is often challenged in court.

Why Do Officers Use Non-Standardised Field Sobriety Tests?

Officers use Non-Standardised Field Sobriety Tests to further assess a driver's cognitive and physical abilities. The officer seeks more evidence of impairment beyond the standardised tests. These tests can reveal issues with memory, attention, and coordination. Officers use these tests as supplementary tools. The officer's primary tools are the Standardised Field Sobriety Tests.
The officer uses Non-Standardised Field Sobriety Tests. The officer strengthens a case. The officer builds a cumulative picture of impairment. These tests provide additional subjective observations. The officer documents all observations from these tests. This documentation is included in the officer's report.

FAQS

What is the purpose of Field Sobriety Tests?

The purpose of Field Sobriety Tests is to provide officers with observable clues. These clues help officers determine if a driver is impaired. The tests assess a driver's physical and mental faculties. Officers use the test results to establish probable cause for a DWI arrest.

Can I refuse Field Sobriety Tests?

You can refuse Field Sobriety Tests. There are no direct legal penalties for refusing these tests. Refusal of these tests does not automatically lead to an arrest. Refusal of these tests might be considered evidence of guilt by an officer.

Are Field Sobriety Tests accurate?

Field Sobriety Tests are accurate to varying degrees. The Horizontal Gaze Nystagmus test is the most scientifically reliable test. Other factors can influence test results. Medical conditions, fatigue, and nervousness can affect performance.

What happens if I fail a Field Sobriety Test?

What happens if a driver fails a Field Sobriety Test? A driver's failure of a Field Sobriety Test provides probable cause for an arrest. The officer proceeds with a DWI arrest. An arrest does not equal a conviction. A driver has legal options after an arrest.

Should I perform Field Sobriety Tests if asked?

Should I perform Field Sobriety Tests if asked? You do not perform Field Sobriety Tests. Performing the tests provides evidence against you. Refusing the tests has consequences. You have the right to consult with a lawyer.

Related Links