In any DWI case in Minnesota, the chemical evidence (which usually comes in the form of a breath test), plays a very important role. Police officers use two different types of breath tests in Minnesota, the Preliminary Breath Test and the Evidentiary Breath Test. These two tests have significant differences in terms of their legal implications and technology. Let’s take a look at these different breath tests and their purposes.

Preliminary Breath Test

During the Preliminary Breath Test, also known as portable breath test or PBT,  a small handheld device is used by a police officer to measure the blood alcohol concentration level of a suspected drunk driver at the scene of the arrest (before the officer makes the arrest decision).

Although not as reliable as its bigger counterpart, the PBT machine can help an officer come to an arrest decision if the result of the driver’s breath test is close to or above the legal driving limit (which is 0.08 BAC in Minnesota). It’s important to note, however, that the result of the Preliminary Breath Test is usually not permissible for use against the accused driver in court to prove innocence or guilt. Also it’s important to note that refusal to submit to a PBT carries no criminal penalties in Minnesota.  However, it can help establish probable cause for your arrest for DWI.

Evidentiary Breath Test

The Evidentiary Breath Test or the EBT, which is typically done back at the police station (after the arrest has been made) uses a bigger and more precise breath testing machine. The DataMaster is the most commonly used Evidentiary Breath Test machine in Minnesota and in several states for DWI cases.

The DataMaster works by measuring and calculating the blood alcohol concentration in the breath sample of a driver. The printout of the breath test’s result is presented by police officers and prosecutors as evidence in court to prove the driver’s guilt. Refusal to submit to the evidentiary breath test at the police station after an arrest may mean a separate misdemeanor charge for the suspected DWI offender.

How Reliable Are The Breath Test Machines?

A lot of Minnesotans are questioning the reliability of the breath test machines used in Minnesota DWI cases. It’s important to understand that these machines are not perfect and many errors and variables may affect their results.

The DataMaster evidentiary breath test machine result (which is often used as the main evidence against arrested DWI offenders) is still prone to both operator and maintenance errors.  This simply means that if the DataMaster is not properly maintained by operators, it can register erroneous results. Additionally, if breath testing procedures are not properly followed during the test, the results of the test can be deemed invalid by the court.

Human Variables Affecting Breath Test Results

There are human variables which vary from person to person which may cause breath testing machines to register inaccurate BAC results. These variables can make sober drivers appear guilty of drunk driving by showing results of a 0.08 or higher BAC even when their true blood alcohol content is lower. On the flip side, obviously impaired drivers can be considered innocent by police officers even though they actually have a BAC above the legal limit.

Physical variables in the person being tested alter the body’s normal composition, and the breath testing machines are not programmed to adjust to them. Some of the human variables which may cause erroneous DWI breath test results are the following:

• Stress
• Confusion
• Age
• Illnesses
• Fear of Police
• Fatigue
• Prescription Medication
• Weight

Challenging Minnesota Breath Test Results

There are many ways to challenge the results of breath tests in Minnesota, and their effectiveness really depends on the expertise of your Minnesota DWI Defense Attorney. Some methods of challenging these tests are successful, and some fail. An experienced DWI attorney is up to date on all the recent changes in Minnesota DWI laws, and knows the angle and argument to make for each unique DWI case. Sometimes this can lead to a dismissal of your case and sometimes it leads to lower DWI penalties. If your DWI attorney is able to successfully attack the evidence against you in court, the result of your breath test will be thrown out and usually at that point the prosecutor will no longer have enough evidence to proceed with your DWI case.

Are You Seeking To Challenge Your DWI Charge?

If you’re charged with DWI in Minnesota, you need to immediately contact an experienced DWI Lawyer to examine how your physical variables, or the condition of the breath test machine could have affected the result of your breath test.

Minneapolis DWI lawyer Douglas T. Kans has the expertise and ability to provide you with the best strategy in defending your DWI charge. You can contact Kans Law Firm at (952) 835-6314 for a free case review.