blog home DUI Defense More Than Just a Breathalyzer: How Does Law Enforcement Test for a DUI?

More Than Just a Breathalyzer: How Does Law Enforcement Test for a DUI?

By Timothy Bussey on September 17, 2019

If you are pulled over on suspicion of driving under the influence in Colorado, the officer may ask you to take a preliminary breath test. At this stage, you have the legal right to refuse the breath test and any field sobriety tests without penalty. The preliminary breath test is one factor law enforcement uses to determine if there is probable cause to arrest you. If you are, in fact, arrested, you will be asked to take an evidentiary breath or blood test, in which case refusal will have severe penalties.

Your best course of action in this situation is to speak with an experienced Colorado Springs DUI attorney. Contact The Bussey Law Firm, P.C., at (719) 475-2555 to get a dedicated legal advocate on your side.

How Does Breath Testing for DUI Work?

In recent years, the State of Colorado has upgraded its evidentiary breath-testing equipment from the Intoxilyzer 5000 to the Intoxilyzer 9000, both of which are manufactured by CMI Inc. The Intoxilyzer is more than just a breathalyzer – both of these machines work on the theory of infrared absorption. Attorney Timothy R. Bussey is certified to operate and maintain the Intoxilyzer 5000.

A person suspected of or under arrest for DUI blows into a breath tube that leads into a breath chamber cylinder in the machine. There is an infrared light bulb at one end of the cylinder and filter wheels at the other end. On the other side of the filter wheels is a light receiver. As the machine shines light through the breath chamber, the filter wheels are spinning at the other end. The infrared light causes molecules of alcohol to vibrate or absorb light at a particular frequency, while the filter wheels filter out contaminants.

The amount of breath in the sample and any alcohol readings are very small. The machine does a mathematical conversion into far more significant amounts to arrive at a value that can be compared to .08%. Even the slightest error in the process could greatly exaggerate that value.

How Do the Intoxilyzer 5000 and the Intoxilyzer 9000 Compare?

The Intoxilyzer 9000 is the latest infrared, evidentiary breath-alcohol-testing instrument manufactured by CMI Inc. It is a four-filter instrument (as compared to five filters in the 5000) and measures alcohol in the nine-micron range (as compared to 3.5 microns with the 5000). While the Intoxilyzer 5000 uses a halogen lamp as its infrared source, the 9000 uses LED. The 9000 also performs weekly calibration checks automatically, as compared to manual checks that must be perfomed with the 5000. Results with either the Intoxilyzer 5000 or the Intoxilyzer 9000 are only as good as the training, methods, and practices used by the operator.

What Happens If You Choose to Have a Blood Test?

If you are arrested for DUI in Colorado Springs and choose a blood test instead of a breath test, forensic chromatography comes into the picture. You may be taken to a hospital to have your blood drawn by a technician, after which the blood is sent to a laboratory for analysis. The blood must be drawn and tested in accordance with specific standards, and there must be a chain of custody for the entire process.

The laboratory uses a gas chromatograph to test your blood, through a process called flame ionization detection (FID), which tests the amount of alcohol in the bloodstream. The gas above your blood is being tested in this process. There is a strict protocol concerning blood-alcohol testing, and it is essential to have a lawyer who knows the science and has the ability to identify errors when they occur in the process.

What About Field Sobriety Tests?

A law enforcement officer may ask you to submit to field sobriety testing during a traffic stop to help determine if you are under the influence of alcohol or drugs. In Colorado, these tests consist of:

  • Horizontal gaze nystagmus (involuntary jerking of the eyes): The driver keeps the head still while following the motion of a pen or penlight with the eyes only.
  • Walk and turn: The driver is instructed to stand in a heel-to-toe position with the arms at the sides, take nine heel-to-toe steps, turn in a specific manner, and take nine steps in the opposite direction while counting the steps out loud.
  • One-leg stand: The officer instructs the driver to stand with feet together, arms at the sides, and raise one foot six inches off the ground, keeping both legs straight. The driver then looks at the elevated foot and counts out loud for thirty seconds, until told to stop.

You are under no legal obligation to take field sobriety tests. They are simply tools the police use to determine whether or not to arrest you for driving under the influence. If you decline to take field sobriety tests, it is best to do so politely.

Get Experienced Legal Help

A DUI arrest is a serious matter, and it is in your best interests to get legal help right away. Timothy Bussey is one of the only attorneys in Colorado with the ACS Forensic Lawyer-Scientist designation. Call The Bussey Law Firm, P.C., as soon as possible to avoid the potential penalties associated with DUIs. Mr. Bussey can also assist you in fighting the automatic suspenstion of your driver’s license after a DUI arrest. We offer a free, initial 30-minute consultation, so call (719) 475-2555 today.

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