Articles Posted in Breathalyzer

In order to obtain a conviction for a DUI offense, prosecutors must prove beyond a reasonable doubt that the defendant had a blood-alcohol level at or above the legal limit at the time the defendant was operating a motor vehicle. Because police usually rely on a non-portable breath alcohol analyzer or a blood test to prove intoxication, defendants are often not tested until several hours after they have been stopped by police. When a test result after arrest demonstrates a blood alcohol level below the legal limit at the time of the test, police and prosecutors rely on a scientific technique known as retrograde extrapolation to estimate a defendant’s blood alcohol content at the time they were operating a motor vehicle. The Arizona Court of Appeals recently affirmed the aggravated DUI conviction of a defendant whose blood alcohol level had been estimated using retrograde extrapolation.

Retrograde extrapolation is a technique used by police departments and prosecutors to determine and prove a person’s blood-alcohol level at the time they were operating a vehicle, as opposed to when the sample was actually collected. Crime lab chemists will apply a formula that approximate the average rate of decline and a person’s blood-alcohol level and use that to estimate a person’s blood-alcohol level at a time prior to the sample being taken. Although Arizona courts accept retrograde extrapolation as a method of proving intoxication, it is far from a perfect science.

The results of a retrograde extrapolation can be inaccurate for several reasons. First, each person metabolizes alcohol at a different rate, and simply applying the average rate of metabolization to every sample guarantees some inaccurate results. Furthermore, if a defendant consumed alcohol shortly before their arrest, their blood alcohol level may increase rather than decrease in the time before their sample is taken. If standard retrograde extrapolation is applied, the result would be inflated and inaccurate.

One of the biggest fears for most motorists is seeing the red-and-blue lights of a police officer’s patrol car flick on in their rear-view mirror. While the process of getting pulled over is stressful for anyone, this is especially the case for those who have had a drink or two. For many motorists, the thought of refusing a breath test crosses their mind. However, there is a lot of misinformation when it comes to Arizona breath test refusals. In this post, we discuss what a refusal is, and its legal significance.

Arizona has what is called an “implied consent” law. Under this law, motorists agree to submit to a breath test when they are pulled over by a police officer, and the officer has reasonable grounds to believe that they are intoxicated. Of course, a police officer cannot physically force someone to take a breath test. So, motorists always have the ability (not necessarily the right) to refuse a test.

When someone refuses an Arizona breath test, that starts a series of events in motion that cannot be undone. As soon as someone refuses a breath test, the officer will take their driver’s license, and their driving privileges will be suspended. The length of the suspension will depend on how many times the driver has refused in the past:

Getting pulled over for a DUI is a terrifying experience. While each Arizona DUI arrest is different, one of the more common ways police officers arrest someone for driving under the influence of alcohol is to tell the driver that they are suspected of DUI and to conduct a roadside breath-alcohol test. Police officers must articulate some basis for requesting a breath test, however, the officer’s subjective belief that a driver is under the influence will often be sufficient. Obviously, introducing this type of subjectivity raises concerns that can be addressed in pre-trial motions to suppress.

Putting the validity of the traffic stop aside for the moment, once an officer determines that a driver is potentially intoxicated, the driver is asked to blow into a tube that is connected to a small machine. The machine analyzes the alcohol content in the driver’s breath, and returns a number that represents an approximation of the person’s blood-alcohol content (BAC). In Arizona, the legal limit is a .08 BAC.

For those unfamiliar with the process, it may seem that once a result above .08 is returned there is no defense and the only option is to plead guilty. The reality is that most people who are arrested for DUI end up pleading guilty to negotiated or reduced charges because it is easier and quicker than taking the case to trial where, if they are found guilty, they may face a more serious sentence. However, if challenged, the prosecution must be able to prove that the machine used to administer the test was accurate, properly calibrated, and correctly used by the police officer.

The most common type of chemical test performed by police in Arizona DUI cases is breath testing. Breath testing measures the amount of alcohol in a person’s breath and converts the figure to blood-alcohol content. Police prefer breath testing in many cases because it is faster and less expensive than blood or urine testing.

Practically speaking, absent physical coercion, breath testing cannot be performed without a driver’s consent. However, under Arizona’s implied consent statute, any motorist who “operates a motor vehicle in this state gives consent … to tests of the person’s blood, breath, urine or other bodily substance for the purpose of determining alcohol concentration or drug content” if they are arrested for suspicion of driving under the influence of drugs or alcohol. Thus, while a motorist can physically refuse to provide a sample, they do not have the legal right to do so. Of course, to rely on the implied consent statute, police must provide a defendant with their rights and the consequences of refusal.

What Happens When Police Don’t Follow the Law?

Generally speaking, when police obtain evidence obtained through improper, illegal, or unconstitutional means, that evidence must be suppressed. This concept is referred to as the exclusionary rule, and is a judicially-created doctrine to deter improper police conduct. Indeed, the United States Supreme Court has held that when a defendant’s blood was taken without a warrant or his consent, the blood-test results were inadmissible. The Court based its holding on the inherent privacy interest a person has in their blood and the intrusive means of obtaining a blood sample. However, in a subsequent case, the Court distinguished between taking a defendant’s blood and using a breath sample. This left an open question regarding the admissibility of breath-test evidence that was obtained in violation of the implied consent statute.

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When you're charged with drunk driving, it can have a major impact on your life. Simply getting to and from work may become a major hassle. That's why it's important to speak with a DUI defense lawyer familiar with Phoenix and Arizona drunk driving laws. An attorney's experience with DUI cases can be crucial for you as you attempt to get charges dropped.

The fact of the matter is that there are many potential flaws when a police officer measures sobriety. We have talked about DUI breath test problems and false positives many times. Right now, we want to address a popular topic about breathalyzer tests. Some people say that using mouthwash can cause you to fail a breathalyzer. Let's look into the issue in more detail.

How a Breathalyzer Works

A breathalyzer is a device that law enforcement uses to measure the amount of alcohol on a driver's breath. The breathalyzer works in a simple fashion. Drivers are asked to blow into a straw attached to the breathalyzer machine. The breath is analyzed and a read of alcohol content is provided to law enforcement. This is one of the ways that police can assess intoxication.

There are flaws with breath testing, however, and a Phoenix DUI defense attorney can help address them. Let's consider the problems with breath tests and then see whether or not you should refuse a breathalyzer test from a police officer.

Problems with Breath Tests to Assess Sobriety

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