Arizona DUI Investigations

An Arizona DUI investigation begins even before you are stopped by police and continues until you are either booked into jail or released.  The training DUI officers receive is almost always based on the Nation Highway Traffic Safety Administration (“NHTSA”) Manual.  An experienced DUI attorney should be familiar with (and preferably own) this manual and the guidelines it contains.  Much of the NHTSA manual is based on “scientific” studies conducted for or by the federal government.  The common stages of an Arizona DUI investigation are:

The Stop

One of the things the NHTSA manual provides is a list of “driving clues” as they relate to possible impairment.  Many of these clues also happen to be traffic violations, but some are not.  While they are on patrol, DUI officers are looking for drivers exhibiting these clues.   Of course, the police can always stop a vehicle if they observe any traffic violation or reasonably believe the driver was involved in a crime, but the NHTSA clues can provide them with reason to stop a vehicle even when they haven’t seen a traffic violation.

Initial Contact

When a DUI officer approaches a vehicle after a traffic stop, he or she will be looking for any contraband inside of the vehicle and any sign that the driver is impaired.  Signs and symptoms of impairment usually noted on police reports are: red, watery, and bloodshot eyes; a flushed face; slurred speech; the odor of alcohol or drugs; mood swings and other unusual behavior; and the fumbling of documents or the inability to find documents.  An officer will usually observe these things after initiating a conversation with the driver and asking the driver for his license, registration, and proof of insurance.  Officers will also typically ask the driver whether they have had anything to drink.  If the answer is yes, or if the officer has observed signs or symptoms of impairment, the officer will then ask the driver to exit the vehicle to conduct field sobriety tests.  When the driver gets out, the officer will look for additional evidence of impairment, like using the vehicle’s door for support, poor balance or coordination, difficulty walking, and swaying while standing.

Field Sobriety Tests

There are several field sobriety tests (“FSTs”) used by law enforcement in Arizona.  Only a few of these tests are actually validated (or backed by studies) by NHTSA.  The primary FSTs are the Horizontal Gaze Nystagmus test, the Walk and Turn test, and the One-Leg Stand test.  These tests are standardized, meaning that the tests must be administered pursuant to the standards set forth by NHTSA in order to be valid.  According to NHSTA standards, some of these tests should not be conducted on certain people (people who are overweight, the elderly, and people who have certain injuries or medical conditions).  These tests are also supposed to be used in combination, as a battery, to determine whether a driver is likely to be impaired.  In other words, if all three tests are not given, the validity of the results is questionable.  A driver has the right to refuse to take field sobriety tests.  This refusal can usually be used as evidence against against you, but it is often less damaging evidence than poor performance on the tests would be.

Following the FSTs, officers will often administer a Preliminary Breath Test (“PBT”) to check their results.  This is a small, hand-held breath testing device, as opposed to the much larger Intoxilyzer 8000 typically used in Arizona.  The PBT is not accurate enough to be admissible as evidence in court, so it is typically only used to confirm the presence of alcohol and/or establish probable cause to make an arrest.

Post-Arrest / Chemical Test

If a DUI investigation has provided an officer with probable cause to arrest the suspect, an arrest will be made.  This does not necessarily mean that the suspect will be taken into custody or booked into jail.  While it is within the officer’s discretion to do so, it is more common that the suspect in a misdemeanor DUI case is cited and released to a third party.

After an arrest, the officer will ask the suspect to submit to a chemical test.  Depending on the arresting agency and the circumstances, this is usually a breath test or a blood test.  A suspect has the right to refuse a chemical test, but doing so will result in an automatic one-year suspension of his Arizona driver’s license.  Moreover, the officer can obtain a warrant for the suspects blood by calling a judge and then forcibly take it.  Thus, it’s usually a good idea to consent to a chemical test.  Breath test results are available immediately, while blood test results can take months because of backlogs at the crime lab.  Even when a blood test is taken and the blood alcohol concentration (“BAC”) is unknown at the time of arrest, the suspect will be charged with driving or being in actual physical control of a vehicle while impaired to the slightest degree.  This DUI charge does not require any particular BAC.  Once the results come back, addition charges are often added.

If you are facing DUI charges in Arizona, it is critical that you are represented by an experienced DUI attorney who knows every aspect of an Arizona DUI investigation.  At Leonardo Law Offices, we are experienced in handling felony and misdemeanor DUI cases, including extreme and super-extreme DUI charges, and have had good results.  For a free assessment of your case, call our Tucson, Arizona office at (520) 314-4125 or contact us online.


Consult the following links for more information about Arizona Criminal and DUI laws, as well as local court information:

Arizona Revised Statutes

Tucson City Court

Pima County Justice Court

Pima County Superior Court

Maricopa County Superior Court

Pinal County Courts

Santa Cruz County Courts

BAC Calculator

Other Links