Robert Christian Billar DUI/DWI Law Blog on Lawyers.com

A police officer who notices that you are driving outside the traffic lane lines, driving at erratic speeds, driving with an expired license tag, or committing any other traffic violation may pull you over. 

The police are allowed to ask for your driver’s license, ask you questions about where you have been, or make conversation.  The purpose of questioning you is to give the officer time to observe whether your eyes are bloodshot, your speech is slurred, your behavior is unusual, or whether you have alcohol on your breath. 

If the officer observes any behavior that indicates drinking, or you provide answers to an officer’s questions that lead the officer to believe you have been drinking, then the officer has probable cause to further investigate or arrest you.

Probable cause

Probable cause is commonly defined as a reasonable belief that a person has committed a crime.  Or, based on a reasonable suspicion because of particular circumstances, a strong justification exists to believe a crime was committed. 
When a police officer has a high level of certainty that you have been drinking, he may arrest you or take you to the police station for testing.  Or the officer may ask you to take a field sobriety test.  If the officer notices evidence of wrongdoing in your car in plain view, such as open beverage containers, weapons, or drugs, this is also probably cause. phoenix drug crime attorneys

Protection against illegal searches

If probably cause does not exist, you are not obligated to allow the police to search your car or trunk.  Officers often ask to search vehicles without probable cause, making drivers feel intimidated and unable to refuse.  However, drivers are well within their rights to refuse an illegal search.

Field sobriety tests

Police are allowed to request drivers to perform field sobriety tests.  The scientific community recognizes three field sobriety tests as standard:

• Nystagmus.  Also called the horizontal and vertical gaze, the officer places a finger or pen 12-15 inches from your face and moves it from side to side to see if your eyeball involuntarily jerks, a possible sign of alcohol consumption.
  Walk and turn.  Walking heel-to-toe along a line, the driver must take nine steps and then turn and take nine steps the other direction.  This exercise tests balance.
• One leg stand.  Standing with heels together and arms at your side, you must raise one leg six inches from the ground and count until the officer has you stop counting.  Loss of balance, swaying, etc. is observed.
• Blood alcohol content (BAC) tests
  Chemical tests are used to determine blood alcohol and include blood, urine, and breath tests administered at the police station, hospital, or testing facility. 
  You are within your legal rights refuse to answer questions until you have spoken with your lawyer.  And you may refuse to submit to a BAC test.  However, refusing generally results in a mandatory license suspension, so it is recommended to submit to a BAC test when requested. 

An Arizona criminal defense lawyer can advise you regarding the outcome at a later date and save your driving privileges—at least in the short term. phoenix dui attorneys

Billar & Donald, P.C.
2700 North Central Avenue, Suite 320
Phoenix, AZ 85004