Phoenix DUI Lawyer Blog

1. DUI Portable Breath Test (PBT)
If stopped for suspicion of Arizona DUI, the police will ask you a series of questions. Possibly before or after requesting AZ DUI field sobriety tests (FST) the Arizona police will request to have you blow into a small hand held device on the side of the road, in an effort to continue building a case to charge you with a DUI in Arizona.

This small device is called a portable breath test (PBT). The purpose is to determine if you were drinking alcohol and supply an approximate reading of how much was in your system. This device can be used as evidence of probable cause to make an arrest for an Arizona DUI, or Arizona DWI. You can think of this one as a preliminary test. The reading on this machine cannot be used against you as evidence in court because it has not passed the necessary scientific tests to be considered an accurate alcohol concentration measuring device to meet proper AZ DUI Law testing standards. It has not been calibrated or maintained for reliability.

If the reading was 0.0 blood alcohol content (BAC) police may still suspect you of driving while drug impaired. In that event, they may continue their investigation with drug impairment testing for AZ DUI drug charges.

2. DUI Breath Test
In Arizona, the official breath test for Arizona DUI testing is done with the Intoxilyzer device. The machine analyzes the DUI suspect's breath sample without destroying it through a process of infrared spectroscopy, thereby determining the amount of ethyl alcohol present in the sample.

This machine is required to be calibrated and tested on a regular basis by the police agencies responsible for them. At times, like all machines, they have problems and may need to be taken out of service for repair or sent back to the manufacturer. It is imperative to inspect the machine records to determine if it was working properly. If a history of prior problems or defects exists with the machine, the machine and results may be invalid, and the evidence may be suppressed. In absence of machine defect or administration error, these machine results are valid and may be used as evidence against you in trial.

Top Arizona DUI defense Attorney will examine all of these elements. Your AZ DUI Lawyer should understand the factors that may affect the accuracy of the machine readings, including test protocol, temperature, and individual human body variances that may affect the outcome of your test results and your AZ DUI case. That is why it is important to select an experienced Arizona DUI lawyer who will have invalid evidence against you thrown out, and make efforts to help you avoid an Arizona DUI conviction.