For decades, American law enforcement has used field sobriety tests on suspected drunk drivers. They have the support of the U.S. National Highway Transportation Safety Administration (NHTSA), which has authorized three “standardized” tests that it says are reliable indicators if a driver is under the effects of alcohol or drugs.
The truth is, these tests are less scientific and often less accurate than a breath or blood test. If the officer who pulled you over administers field sobriety tests improperly, you might end up getting arrested even though you did not break the law.
The standardized and non-standardized field sobriety tests
The three standardized tests are:
- Horizontal gaze nystagmus (HGN) test
- Walk-and-turn test
- One-leg stand test
For the HGN test, the officer will pass a pen, finger or other object across your gaze and order you to follow it with your eyes. If your eyes do not move from side to side smoothly, this is supposed to be a sign of intoxication. The walk and turn test involves walking heel-to-toe for nine steps, turning and walking back the same way. That and the one-leg stand test are supposedly indicators of whether your balance, coordination and ability to follow instructions are being affected by alcohol.
In addition, California police often use “non-standardized” tests like the finger-to-nose test (where you close your eyes, hold your arms out to your sides and touch your nose with each hand three times) and the Rhomberg balance test (where you stand with your feet together, eyes closed and head tilted back, until you believe 30 seconds have passed).
The biggest flaw with field sobriety tests is that they rely on the police officer’s judgment. With a breath test or blood test, assuming they were correctly administered and the machine functioned correctly, you get an accurate reading of your blood-alcohol concentration at the time of the test. Not so with field sobriety tests. It is up to the officer whether you pass or fail a test. An inexperienced or incompetent cop or deputy could decide a sober person is intoxicated.
Another problem is that several things can make a person “fail” a field sobriety test besides drugs or alcohol in their system. Things like weather, the slant of the road, the driver’s age, disability status and nerves can all come into play. But if the officer administering the tests does not recognize what really made you stumble or lose your balance, they might arrest you unfairly. Then you will have to challenge the evidence in court and fight to get the DUI charges reduced or dismissed.