Officers administer field sobriety tests incorrectly 97% of the time

Recently Lance Platt, a certified NHTSA SFST practitioner, instructor and trainer, published a paper in the DWI Journal: Law & Science that examined the differences between the manner in which officer are trained to perform field sobriety tests and the manner in which they actually administer them.

For the Horizontal Gaze Nystagmus test, Mr. Platt recognized 16 elements that make up the test. After examining 360 recorded evaluations, he found only 24 were performed correctly per the NHTSA Manual. Those 24 represent only 7% of the tests administered, meaning that officers administered the test incorrectly 93% of the time.

HGN Test Elements

• Place feet together
  
• Place hands to your sides
  
• Maintain the position
  
• Look at the stimulus
  
• Follow the stimulus with your eyes only
  
• Do not move your head
  
• Continue to follow the stimulus until the test is complete
  
• Do you understand?
  
• Officer positions stimulus correctly
  
• Officer checks for equal tracking
  
• Officer checks for equal pupil size
  
• Lack of smoot pursuit (timing element)
  
• Distinct & sustained nystagmus at maximum deviation (timing element)
  
• Onset of nystagmus prior to 45 degrees (timing element)
  
• Vertical gaze nystagmus
  
• Possible optokinetic (environmental issue)
  

For the Walk and Turn test, Mr. Platt recognized 21 elements that make up the test. Of the 360 recorded evaluations, he found that only 67 were administered correctly per NHTSA. In other words, officers administered the test incorrectly 81% of the time.

Walk and Turn Elements

• Imagine a line
  
• Place your left foot on the line
  
• Place your right foot in front of your left
  
• Touch the heel of your right foot to the toe of your left
  
• Keep you arms to your sides
  
• Remain in this position and do not start walking until told
  
• Do you understand?
  
• Take nine heel-to-toe steps up the line
  
• Turn by leaving the lead foot on the line and taking a series of small steps
  
• Take nine heel-to-toe steps back down the line
  
• Officer demonstrates walking phse
  
• Officer demonstrates turn
  
• Look at your feet
  
• Count your steps out loud
  
• Keep arms at your side while walking
  
• Do not stop walking
  
• Do you understand?
  
• Begin walking and count your first step forward from the heel-to-toe position as step number one
  
• Poor testing surface
  
• Issues with shoes
  
• Weather
  

For the One Leg Stand test, Mr. Platt recognized 16 elements that make up the test. Of the 360 recorded evaluations, he found that officers administered the test correctly only 50% of the time.

One Leg Stand Elements

• Place feet together side by side
  
• Keep your arms to your sides
  
• Remain in this position and do not start until told
  
• Do you understand?
  
• Keep both legs straight
  
• Keep your arms by your sides
  
• Lift the leg of your choice
  
• Approximately 6 inches off the ground
  
• Point the toe of the elevated foot parallel to the ground
  
• Look down at the raised foot
  
• Count out loud by 1000's until told to stop
  
• Do you understand?
  
• Officer demonstrates balance and counting
  
• Poor testing surface
  
• Issues with shoes
  
• Weather

When he evaluated in how many of the 360 test sequences all three tests were administered correctly, he found that only occurred ten (10) times, meaning that officers administered at least one test wrong 97% of the time.

Unfortunately in Texas judges routinely hold that the incorrect administration of these tests goes to the weight, not the admissibility, of the evidence. This despite the warning in the NHTSA Manual that "if any of the standardized field sobriety test elements is changed, the validity is compromised."