Tests used to determine if you are driving drunk

Jon Bryant Artz DUI and Criminal Attorney, Lecturer and Editorial Consultant
Tests used to determine if you are driving drunk

When the police pull you over, they will use a variety of visual cues to determine if you have been drinking. If the officer thinks you have been drinking, he/she will have you exit the vehicle and ask you to perform field sobriety tests. The police will use the results of these test to determine if they have probable cause to arrest you for a DUI or DWI.

The two main tests the police will use to determine if you were driving drunk are the following: 

Field Sobriety Test and other symptoms of being drunk

To determine if you have been drinking, the police look for specific symptoms including slurred speech, red watery eyes, and the odor of alcohol on your breath and clothes. If the police detect any of these they will likely ask you to exit your vehicle and conduct a field sobriety test.

The field sobriety test is usually conducted at the scene where you were stopped by the police. The field sobriety test usually includes a series of simple physical and mental tests such as:

  • Nystagmus test, which checks the eyes for lateral or horizontal jerking when the eye gazes to the side. 
  • recite the alphabet forward and backwards
  • stand feet together, arms at sides, tilt head back, close eyes, and count to 30, then open eyes and drop head back down
  • stand and listen to instructions, then walk in a straight line, turn around, and walk back towards the officer
  • stand with your feet together, tip your head back, close your eyes, and touch your nose with the tip of your index finger as directed by the officer

Remember that when taking a field sobriety test, all your actions are being recorded by the officer and possibly by a camera mounted in the police cruiser. Stay calm, polite, and respectful throughout the ordeal.

The problem with all of the field sobriety tests is that you could fail one or more of the tests as a result of some other physical or mental condition unrelated to your sobriety, or due to nerves or anxiety. Failed sobriety tests do not determine whether a person is, or is not, under the influence. If you did submit to a field sobriety test, write down all the tests you did and how you performed as soon as you can after the arrest.  Here are 17 questions you should answer and provide to your DUI Lawyer.

It is legal to refuse to take any of the field sobriety tests. Given the subjective nature of the tests, it is often recommended that you politely refuse to take them. However, this means you will probably be arrested and asked to take a chemical test. Refusal to take a chemical test usually carries a penalty (check your state laws) such as suspension of driving privileges for at least one year.

The chemical blood test or breath test is a more accurate reading of your blood alcohol content level. They are often administered at a hospital or detainment center, which is usually some time after you were initially pulled over or stopped by the police. The more time between when you were pulled over and when you take the chemical blood or breath test, the better your chances of mounting an effective DUI defense.

Chemical Blood Test and Breath Test

Chemical blood tests analyze your breath, blood, or urine to determine your blood-alcohol concentration (BAC). If your BAC is .08 percent or higher, you are considered legally under the influence and will be charged with a DUI, and possibly a second charge, driving with BAC of .08 percent or higher. Blood and urine tests are usually conducted at a hospital. A breath test can be conducted either at the place you were pulled over, a hospital, or a detention center. Though usually the breath test is at the police station.
 
There are two types of breath tests: pre and post arrest. A pre-arrest breath test is usually conducted at the roadside where you were stopped by the police, and uses a portable hand-held device called a breathalyzer.  It is recommended you politely refuse this test. This is perfectly legal. There are many issues with the roadside breath test because the technology is suspect. For example, it can show artificially high readings and does not have the safeguards of the better breath devices used at the police station.

A blood-alcohol concentration of .08 percent obtained from a chemical test will result in you being charged with a DUI. But it does not mean you are, or will be, found guilty of a DUI. Even with a blood alcohol content of .08 percent or more, the DUI lawyer you hire will know many valid reasons that can be used in your DUI Defense.

Photo Credits: Field sobriety test by Flickr: OregonDOT

Jon Bryant ArtzDUI and Criminal Attorney, Lecturer and Editorial Consultant

Mr. Artz has successfully defended in excess of 3000 DUI cases. He has tried to a jury more than 300 trials. He is also an editorial consultant for “California Drunk Driving Law”, a 2 volume treatise on DUI. He received his B.S. degree in ec...

View Full ProfileRecent Articles