Field Sobriety Tests

Field Sobriety Tests

Even if you have never been pulled over by the police for suspicion of drunk driving, you are probably aware of what commonly happens to those who are. The officer will come up to your window, ask for your license and registration, and discreetly slip into a less formal conversation. If you are ever in this situation, it is important that you limit the extent to which you engage in conversation. Generally, the police are not that interested in where you are going or where you are coming from, except if you just came from a tavern. These questions are designed to get drivers to talk more and reveal tell-tale signs of intoxication. If they are not completely satisfied that you are sober, they may ask you to “voluntarily” take some field sobriety tests.

The first thing to remember about field sobriety tests is that they are voluntary. Because they are designed to gather evidence of a crime – the crime of driving under the influence of intoxicants (DUII) – they are considered a “search” under the Oregon Constitution and the U.S. Constitution. Both of these Constitutions prohibit “unreasonable” searches. In order for a search to be “reasonable,” the police either need to have a warrant, or the search would have to fall within a certain set of exceptions to the warrant requirement. One of these exceptions to the warrant requirement is if you consent to the search – if you agree to let the search happen, then you are saying that you will not exercise your Constitutional right to refuse a warrantless search.

Which brings us to the second thing to remember about field sobriety tests: While the police assume that the tests will give them evidence that you are driving drunk, they can also give evidence that you are not under the influence. 

If you have already been pulled over, subjected to field sobriety tests, arrested and charged for DUII, it might seem like a lost cause.  You might be right or you might be wrong.  Some people look totally fine when they do the tests yet the officer will still make the arrest. Some people look to the police officer like they are confused and have balance problems when, in fact, that is how the person ordinarily looks and acts. 

Here are three of the field sobriety tests that Oregon police use.

Horizontal Gaze Nystagmus

One of the most common field sobriety tests used, the Horizontal Gaze Nystagmus is designed to detect involuntary eye movement that commonly occurs after drinking alcohol. In the test, the police officer will hold up a pen, or a finger, about twelve to fifteen inches in front of your nose. While you hold your head still, the officer will move the pen to the side and into your peripheral vision, to see if your eyes can smoothly track the motion. The officer will hold the pen way out to the side for at least four seconds to see if they can percieve what is called "nystagmus at maximum deviation." Then, they will place the pen in the center and move it slowly out to the side until they reach the 45 degree angle. It should take no less than 4 seconds for this movement. The offier is looking for the onset of nystagmus rior to the 45 degree angle. 

Data collected by the National Highway Transportation Safety Administration (NHTSA) determined that the test was the most accurate of all the tests in determining if you have any alcohol in your blood system. However, in Oregon, if this test is not performed in the prescribed manner, the test is inadmissible. Be advised that if you have a blood alcohol concentration of 0.04 you should fail this test. 


In the Walk-and-Turn, a cop will ask you to walk a line, putting the heel of one foot to the toes of the other foot, rather than typical steps, all while holding your hands at your sides, looking at your feet, and counting the steps. They will then have you turn at the end of the line, and walk back.

The Walk-and-Turn tests your ability to multitask, as well as your balance. Police watch for eight clues that indicate intoxication:

  • Inability to keep balance when you have one foot in front of the other while the officer instructs and demonstrates,
  • Beginning before the instructions are finished and you are told to begin,
  • Stopping while walking the line, in order to regain balance,
  • Not touching your heel to your opposite toe, (a gap of more than half an inch)
  • Stepping off the line, (the entire foot must be off the imaginarey line)
  • Raising your arms more than six inches from your sides,
  • At the end of the line, turning differently than the way the officer instructed,
  • Taking an incorrect number of steps

Showing two of these things means that you fail the test. Most sober people will show two or more clues.

One Leg Stand

The last test that is usually given is called the one leg stand. The officer will have you stand with your feet together and hands to your side. The officer will tell you that when he tells you, lift a leg of your choise, six inches off the ground, with both legs straight. You will be told to count out loud by thousands until you are told to stop. You are to keep your hands to your sides and look down at your raised foot. The test is supposed to last 30 seconds. The officer is looking to see if you sway, hop, raise your arms more that 6 inches from your side, or place your foot down. The officer will consider your test a failure if you do two of thise things. 

Other field sobriety tests have similar holes in them. In my years defending against DUII charges, I have seen very few people not “fail” the field sobriety tests, even those with zero alcohol and zero drugs in their system. 

Shopping Around

You can expect a very productive telephone conversation. Office consultations are available on an hourly fee basis.

Peter Carini, Esq.
Mon: 08:00am - 07:00pm
Tue: 08:00am - 07:00pm
Wed: 08:00am - 07:00pm
Thu: 08:00am - 07:00pm
Fri: 08:00am - 07:00pm
Sat: 08:00am - 07:00pm
Sun: 08:00am - 07:00pm