Field Sobriety Tests
The National Highway Traffic Safety Administration (NHTSA) has developed a set of Standard Field Sobriety Testing (SFST). These are psychophysical tests administered by law enforcement to determine if an individual is under the influence of alcohol.
The SFSTs consist of three tests:
- Horizontal Gaze Nystagmus (HGN)
- One-Leg Stand
These tests are meant to be administered and evaluated/scored in a standardized way in order to obtain validated clues of impairment. The officer uses these clues to establish probable cause for arrest.
Don’t Do the Tests:
You cannot be compelled to do them. The SFSTs are 100% voluntary. They are designed to aid law enforcement in evidence gathering, and prosecutors in getting convictions.
By refusing the tests, you are taking away one of the biggest parts of the State’s case against you. Remember, the burden to prove intoxication beyond a reasonable doubt is on the State.
You have a Right to Remain Silent:
The 5th Amendment is powerful. Among other things, it provides everyone with the right to remain silent.
The officer is going to ask you questions. You do not have to answer them.
By refusing to participate in the SFSTs, and by staying tight-lipped, you are very likely going to aggravate the officer, and you may very likely be arrested. Resist the urge to get out of the arrest. Anything you do and say will be used against you.
By sticking to your guns and exercising your rights, you will put yourself in the best position to ultimately beat whatever charge is brought against you. Read more here. (link to blog)
The Standard Field Sobriety Tests:
If you did the tests, not all hope is lost. The NHTSA Manual itself states that the SFSTs can be compromised if any one element of any test is not conducted properly.
I have the same training in SFST administration that law enforcement officers receive. One of the very first things I will do is review the video in your case to determine if the tests were administered correctly. They often are not.
Horizontal Gaze Nystagmus Test (HGN)
HGN is an involuntary jerking of the eyes that occurs naturally when you gaze to the side. Normally, this jerking movement happens when the eyes are rotated at high peripheral angles. Alcohol impairment can exaggerate this jerking. and can occur at lesser angles.
The officer performing the test is trained to look for three clues in each eye:
- Lack of Smooth Pursuit: Where the eyes cannot follow a moving object smoothly.
- Distinct and Sustained nystagmus at Maximum Deviation: If jerking is distinctly noticeable when the eye is looking as far to the side as it can.
- Onset of Nystagmus Prior to 45 Degrees: If the jerking starts when the eye is within 45 degrees of center.
After testing both eyes, if four or more of the indicators are observed, then the police count that as a sign of intoxication.
Of the hundreds of DWI reports I’ve reviewed, almost all of them score for 6 clues, which is the maximum. It’s easy to do this because there is absolutely zero way to check the officer on this.
Click here to read more about why the HGN test is unreliable.
The Walk and Turn Test (WAT):
Remember playing Simon Says as a child? The WAT is the impromptu, roadside version of that. This is an attention diverted task, with no room for error, and no practice rounds.
The WAT has 15 different instructions, and the officer is trained to score for impairment after only two errors. equal a sign of impairment to the officer.
Here are the clues:
- Can’t Balance During Instructions: If you can’t stay balanced during the instructions
- Starts Too Soon: If you start walking before the instructions are finished
- Stops While Walking: If you stop during the test
- Misses Heel to Toe: If you fail to touch heel-to-toe by half an inch
- Raises Arms: If you raise your arms more than six inches from the body for balance
Improper Turn: If you don’t do a series of small steps or fail to turn to the left direction
- Wrong Number of Steps: If you take an incorrect number of steps going or coming
- Steps Off The Line: if you step off the imaginary or designated straight line
Click here to read more about why the WAT is unreliable.
The One Leg Stand Test (OLS):
You stand on one leg and count to 30.
The One-Leg Stand Test has 13 different instructions. There are four possible clues, and it only takes two for the officer to score for signs of impairment. The clues are:
- Sways – If you sway while balancing
- Raises Arms – If you raises your arms more than six inches
- Hops – If you hop to maintain balance.
- Puts Foot Down – If you put your foot down.
Click here to read more about why the OLS is unreliable.
Every officer that administers these tests will describe their observations in their report. As discussed above, this is where consistency becomes important. If the officer’s observations don’t match what is clearly shown on video, the credibility of the officer, and the arrest begin to be called into question.
The officer’s report is biased. Your personal recollection is biased. The video is the great equalizer. It shows what it shows.