THE DEFINITIVE GUIDE TO DEFEATING AN ARIZONA DUI
Including Forensic & Constitutional Challenges
Successfully Defending DUI Offenses
PROFESSIONAL DUI & VEHICULAR CRIMES FIRM IN PHOENIX, AZ
If you can’t imagine how an Arizona DUI charge could be defeated, a case dismissed or evidence suppressed then you are not alone. Most jurors (start off) thinking these cases are cut and dry as well. For that matter, many attorneys don’t have the expertise to identify the makings of a strong defense.
However, there are people in Arizona who have won a DUI, been found not guilty of vehicular manslaughter and had their evidence suppressed in an Aggravated DUI case. It happens much more than you might think. Does it happen to all my clients? Of course not. However, it happens…more than it should. If you have been accused of an impaired driving offense then the information will help you understand how these case can successfully be defended. If you are a lawyer seeking to help own clients fight a DUI then this page should also provide the necessary strategy and tactics.
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Forensic Evidence Challenges
There are no DUI cases without forensic evidence. A result of an alleged scientific test is usually the end-all be-all of the government’s case. Consequently, the ability to challenge this kind of evidence is the primary challenge in just about every DUI or vehicular crimes case.
Accuracy, Reliability and Validity
Blood test results in DUI cases require proof beyond just a machine’s ability to produce a number.
The process of measuring the amount of ethanol in a blood sample has three phases. First is the pre-analytical phase where blood is drawn from a person, stored and preserved for testing. A material problem occurring in this stage of the process will invalidate any blood test result. Read more about Blood Draw (Phlebotomy) Problems.
Unreliable DUI Calibration
In DUI cases the machine used to measure the amount of alcohol in a blood sample is called a gas chromatograph. The machine does not inherently know how to identify or measure anything – including ethanol. The machine has to be taught to identify alcohol. This process is called calibration. Using reliable calibrators (known amounts of ethanol) is essential to the measurement process.
When the calibrators used to teach the machine lose degrade there is a loss of ethanol. Now the machine’s virtual measuring stick makes things look bigger than they are in reality.
In DUI cases a gas chromatograph is calibrated using calibrators that are a mixture of ethanol and water. A crime lab must address the fact that they are attempting to measure the amount of ethanol in a different matrix – blood.
One issue that is often overlooked is ensuring that the blood sample is allowed to properly warm prior to the measurement process. Blood samples are stored in a refrigerator to preserve sample integrity. However, if they are not allowed to reach room temperature before testing the result can be artificially inflated.
This is how someone who is under the legal limit can get a blood test result above .08; or how a regular DUI falsely becomes a super-extreme DUI.
Contaminated Samples
Independent Analysis
State Ex Rel. McDougall v. Corcoran (Keene), 153 Ariz. 157, 735 P.2d 767 (1987)
Breath Tests for Alcohol
- Partition Rations
- Indirect Measurements
- Infrared spectroscopy
- Breath Temperature
- Hematocrit Radio
- Frequency Interference
- Mouth Alcohol
- Illegal per se offense
- Calibration Need
- Non-specific Analysis
- Interfering Compounds
- Homeostatic variables
- Common Sources of Error
- Henry’s Law
Independent Analysis
Birchfield v. North Dakota, 136 S. Ct. 2160 (2016)
Retrograde Extrapolation
Misusing Field Sobriety Tests
- Correlation v. Causation
- National Highway Traffic Safety Association (NHTSA)
- Nystagmus
- Gaze-Evoked Nystagmus
- Horizontal Gaze Nystagmus
- Walk and Turn Test
- One Leg Stand
- Validated v. Standardized
- Peer Reviewed Published Science
Principles of Forensic Science
- Quality Assurance
- Quality Control
- The Scientific Method
Measurement Uncertainty
Measurements are not true values. The true value of anything you attempt to measure is unknowable. Measurements are just estimations. Some better than others. This is true whenever a lab measures the amount of alcohol in a blood or breath sample in a DUI case
Constitutional Challenges
If you have been arrested for a DUI, Aggravated DUI of Manslaughter in Arizona then you have rights guaranteed by both the United States Constitution and also the Arizona Constitution. Many times people overlook the rights given under the Arizona Constitution. These constitutional protections are the basis of any decision by a court to suppress evidence or dismiss a DUI case.
Illegal Traffic Stops
The police need a reason to pull over your car. How good the reason must be is a complicated question that often has a subjective answer. The law requires that a police officer have reasonable suspicion that a crime was committed to justify a traffic stop.
Illegal Arrests for DUI
To arrest a person for DUI in Arizona the police must have probable cause that you were impaired by alcohol (or a drug). This usually requires probable cause to believe that your alcohol concentration is above the legal limit. So, what is required for them to meet this burden?
Illegal Searches in DUI Cases
The Fourth Amendment to Constitution protects people from unreasonable search and seizures by the government. The Arizona Constitution seems to even go further by giving a right to privacy in your “private affairs.” What does these right really protect in Arizona DUI cases?
Warrantless Seizure of Blood
A warranted seizure of blood is presumed unconstitutional. These types of cases have received a lot of attention from Arizona courts in the last couple of years. There is has been a trend away from allowing warrantless blood draws, but also a tendency towards permitting warrantless breath testing.
- Missouri v. McNeely (2013)
Challenging Search Warrants
Search warrants for a blood sample based on unreliable or false information.
- Franks v. Delaware Motions
Right to Counsel in DUI Cases
In Arizona, the Right to Counsel attaches well before it does under the federal law.
- Choice of counsel
- Sixth Amendment to the United States Constitution
Exculpatory Evidence Rights
Arizona is one of the few states that guarantee the right to independent testing of a blood sample.
Unreliable Identification in DUI Cases
The Right to Confront the Crime Laboratory
- Whether the vehicle was running;
- Whether the ignition was on;
- Where the ignition key was located;
- Where and in what position the driver was found in the vehicle;
- Whether the person was awake or asleep;
- Whether the vehicle’s headlights were on;
- Where the vehicle was stopped…
Arrest Quotas for DUI Cases
Public Records Investigations
Obtaining Police GPS Data
Prior Instances of Untruthfulness
"Lawrence represents very high-profile clients who greatly depend on a good outcome, and this guy will deliver.
This is a prosecutor's worst nightmare, and it should be that way if you need an attorney."
- David E.
Real Client's Husband, Phoenix, AZ
Hiring an Experienced DUI/DWI Attorney
Arizona DUI law is extremely complicated and has severe consequences. DUI law is commonly referred to as a minefield. An attorney must be competent in the Arizona Rules of “Criminal” Procedure, the Arizona Rules of Evidence, the United States and Arizona Constitutions, and the Arizona Department of Motor Vehicles Rules and Regulations.
An attorney cannot do anything for you unless he or she has extensive experience in these areas. Police officers are only human and do commit legal errors. However, only an experienced DUI attorney will be able to find these errors and use them to help his or her client.
You should choose an experienced DUI attorney for the same reason you should choose a qualified doctor. If you break your wrist, you go to a doctor that specializes in wrist injuries. When you are charged with a DUI, you should hire a qualified DUI attorney.
An experienced Arizona DUI attorney can analyze your case for legal errors and defenses. He or she can have blood samples independently analyzed, look for suppression issues, review calibration / COBRA records of breath machines, find the right expert witnesses for your trial, and assist you with your driver’s license issues.
For more information, call our office at (602) 494-3444 or visit our contact page.
What Real People Are Saying
That is, DUI cases actually dismissed. Verifiable not guilty verdicts. Blood alcohol evidence truly suppressed as witnessed by judges, other lawyers, and newspapers.
Real Client's Husband, Phoenix, AZ
"Lawrence represents very high-profile clients who greatly depend on a good outcome, and this guy will deliver.
This is a prosecutors' worse nightmare, and it should be that way if you need an attorney."
- David E.
REAL CLIENT, PHOENIX, AZ
It was miracle!... A lot of people don't really understand the benefit of having an attorney who used to be a prosecutor. They know all the little tricks and scare tactics the state has as opposed to just hiring an attorney who is a little fish in a big pond."
- Joe C.
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For more information, call our office at (602) 494-3444 or fill out the form and we will get back to you.
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