Breath Alcohol Test Defenses in Michigan


A driver of a motor vehicle with a bodily alcohol content (BAC) of .08 percent or above is guilty of operating while intoxicated (OWI) or more commonly known as Drunk Driving. The two predominant ways to determine a BAC is from a breath alcohol test or a blood alcohol test. The most common way to determine BAC in a drunk driving prosecution is a breath alcohol test. The only breath alcohol test that can be used as evidence against an accused in Michigan is called a Datamaster. There are two types of Datamasters, the BAC and the newer DMT.

While a blood test is arguably more accurate and reliable, the breath test for BAC is more commonly used because the test is easier to administer, can be used by non medical personnel, is less physically intrusive to the person taking the test and produces results faster. However, under certain circumstances, breath tests can be less than reliable as an accurate measure of BAC.

The Datamaster, a machine used in the police station after a person has been arrested, tests the alcohol content of a person’s breath. There are many ways to attack the accuracy and reliabiity of this test. Below are several detailed ways an attorney can challenge the Datamaster test.

The Operators Must be Properly Trained and Certified

First, only certified operators can operate the Datamaster machine. Police departments must train and certify selected officers to operate the Datamaster. There are several classes of operators, covering both preliminary breath test (PBTs) instruments and evidential breath test instruments.

The operators must go through training which consists of one training course that takes one day. Your attorney should always verify that the operator is certified to perform the functions that he or she performed in the Defendant’s arrest, and that the operator’s certification was current.

It is also important to determine that the offers administered the test strictly pursuant to their training. They often do not. Barton Morris owns their breath operator training manuals for use in confronting the officers about how they are not following the rules. If they are not administering the tests, the test results are not valid, not accurate and not reliable. When a jury or judge sees this it is highly effective in getting cases dismissed.

The Operator Must Observe the Arrestee for Fifteen Minutes Before Administering the Datamaster Test.

Second, according to the Michigan Administrative Rules regarding breath testing, a person may be administered a breath test using the Datamaster machine only after being observed for fifteen minutes by a police officer. During this period, the officer must make sure the person has not smoked, regurgitated, or placed anything in his or her mouth, except for the mouthpiece of the Datamaster machine. Although the officer does not need to stare continuously at the person, he must be close enough to know what the person is doing.

Taking the Datamaster Test

In preparation for the test, the operator must “purge” the machine. During this process, all chambers and internal plumbing are cleansed of any residual substances by surrounding air, which is pulled through the tube and pumped throughout the instrument. After purging, .000 will appear on the display. The operator must be careful because the breath tube can act like a vacuum cleaner and suck in dirt on the counter. Also, if the driver smells like alcohol, the operator should move him or her from the immediate test area until the purging is complete. This can cause a false reading of alcohol.

When taking the test, the driver blows into a straw-like piece attached to the end of a tube that is connected to the table top Datamaster machine. The person is then asked to blow into the tube for a second test. After the first test, a new individually wrapped mouthpiece must be used for the second test. The person can refuse the second test or there may be an instance where a substance is found in the person’s mouth that would interfere with the test result. At which point, the officer must observe the arrestee for another 15 minutes and start the test again.

All of this can be seen in the booking video that your attorney should request from the arresting agency.

Obtaining the first test sample is enough to be admitted into evidence. The purpose of obtaining a second sample is to confirm the first sample. Confirmation is critical. However, if a second test is given, it must fall within an acceptable range depending on the reading. If the first two are not within an acceptable range, a third sample must be taken. The amount of acceptable variance depends on how high the results are.

So, another way to challenge the Datamaster test results is if the results are beyond the acceptable variance.

Body Temperature Can Affect the Results

The premise of the Datamaster machine is very technical, using infrared spectroscopy. The simplest explanation of the technology is that a light is beamed through the breath sample chamber. The alcohol molecules are absorbed and a detector at the other end of the chamber measures how much light is left then a computer calculates the amount of alcohol percentage is in the breath sample. In addition, the device is designed and programmed to operate on several assumptions, including that the person has a normal body temperature. The higher the body temperature, the higher the breath alcohol result. This is another defense that your attorney should look into. Officers do not check an arrestee’s temperature, but it could certainly have a significant impact on the results.

The Datamaster Must be Properly Calibrated and Maintained

Another way to challenge the Datamaster evidence is if the machine is not checked, tested and calibrated properly. The Datamaster must be simulated at least once a week. The machine is simulated when the officer attaches a device that produces a sample of air similar to the actual test. Instead of a person, the simulator creates the “breath.” In Michigan, the approved machines are the BAC Datamaster and the Datamaster DMT. The state awarded a contract in 2008 for the DMT but the DMT wasn’t put in service in police stations in Lansing until April 2012.  The administrative rules were amended in 2010 to reflect differences between the DMT and the Datamaster. There is no longer a requirement that the check be performed by an appropriate operator because the new machine is designed to conduct a self-check. But, the BAC Datamaster is still in use which requires the calibration by a human operator.

The weekly inspection is intended to verify that the machine is operating accurately. Essentially, calibration involves the operator attaching a separate small device to the Datamaster machine and then breathes into the breath tube of the Datamaster to make sure it works properly. There is an alcohol mix in the simulator device that provides the alcohol readings. The operator must mix his or her own simulator solution for the required weekly tests. The simulator acts literally like a “simulated drunk.” He or she must also check for leaks, check simulator temperature, and equilibrate the simulator before using. The simulator must be heated to 34 degrees Celsius. Once the simulator is heated to the proper temperature, the operator must then blow into it vigorously. This is to cool the air above the solution to equilibrate the temperature of the air and solution.

There is a water based ethanol mix in the simulator that provides the alcohol readings. The simulation must result in a sample that is between .076 and .084 grams per 210 liters of “breath.” The test must not be high or low. The operator is trained to take up to four tests if there are high or low readings. If after the fourth test the results are still high or low, the operator must notify his or her supervisor; notify a service representative; take the unit out of service only if advised to do so by the service representative; place a sign in the unit noting “OUT OF SERVICE.”

All of this must be recorded in the simulator log book to ensure accurate simulations.

As soon as you contact an attorney’s office after your arrest, he or she should submit a request with the arresting police department for these logs. The attorney should then inspect the logs to ensure that the Datamaster machine was properly calibrated each week.

Examination of the maintenance records frequently discovers the police agency is sloppy with their simulation protocols, record keeping and the often ignore error messages produced by the instrument. The inability of the police to properly maintain their Datamaster can be very effective in demonstrating to a jury that a measurement is not reliable.

Each Machine Must be Tested Every 120 Days

The machine must also go through a more thorough inspection every 120 days. The 120 day inspection can only be conducted by a specific class operator or authorized representative of the manufacturer. For this 120 day test, the operator must check for accuracy at three different breath alcohol levels: .040, .080 and .200. The operator must also check for acetone interference, radio interference, the time and date on the instrument and that the thermometer is working.

Your lawyer should always order the 120 day maintenance records to verify the notes by the operator when he or she signs the calibration logs.

Chemical Interference and Breath Alcohol v. Mouth Alcohol

If the Datamaster detects a chemical substance other than ethanol, the test should be stopped and the printout should indicate “INTERFERENCE DETECTED.” The operator should start a new 15-minute observation period and go through the test procedure again.

There are different types of alcohol that could cause interference. Ethyl alcohol, methyl alcohol and isopropanol are three of the most common. Ethyl alcohol is what is in alcoholic beverages, isopropyl alcohol is rubbing alcohol and methyl alcohol is the simplest form of alcohol that is used in industrial processes.

The Datamaster assumes that the only volatile compound in the person’s breath is ethanol. Although it is supposed to be designed to detect other chemicals and produce an interference, the Datamaster is not, in fact, sophisticated enough to determine whether the compound that is reacting to the infrared beam is one of the other forms of alcohol. For example, if a person deals with alcohol for manufacturing and industrial purposes and that alcohol is on that person’s body, hands or clothing, it can factor into the alcohol reading on the Datamaster.

Breath alcohol is from deep lung air while mouth alcohol is what’s left over in your mouth if you were to use mouth wash with alcohol.

To assure mouth alcohol is not present when giving the breath tests, most regulations require a fifteen minute direct observation of the test subject to assure any mouth alcohol from consumption has been eliminated, as discussed above.  The concern for elimination of mouth alcohol is based upon the theory that mouth alcohol can be measured as breath alcohol and therefore invalidates the breath alcohol test results.

Radio Frequency Interference

If the Datamaster detects any radio transmissions in the area that could interfere with a test result, the test should be stopped. Both the display and the printout should indicate “RADIO INTERFERENCE.” After the interference is gone, the operator must press the “run” key to initiate a new test. A new 15 minute observation period is not necessary.

Sometimes, cell phones are being used in the booking room at the same time that the breath test is being administered.  The problem is that cell phones create radio waves, and these waves can interfere with the breath test. Your lawyer should always order the booking videos to see if a cell phone was being used at the time of the breath test, and challenge the test on those grounds.

Human Physiological Defenses

Many people have pre existing medical conditions or circumstances that preclude an accurate and reliable breath alcohol analysis. A breath test should not be performed to people with the following conditions:

Diabetes – If suffering from low blood sugar a diabetic could be in a state of ketoacidosis elevating the amount of acetone in their blood which can be mistaken for ethanol by the Datamaster

Hypoglycemia – Same possible ketoacidosis defense.

Active and persistent Gastro Esophageal Reflux Disorder (GERD) – Causes alcohol to be expelled from the stomach and enters the mouth at which point can be blown into the Datamaster provided an analysis of mouth alcohol and not breath alcohol

Recent traffic accident with injury to mouth or head – Any possible blood in the mouth will possibly cause a mouth alcohol reading and not a breath alcohol analysis.

Recent and persistent regurgitation for any reason causing mouth alcohol to be tested instead of breath alcohol.

Dentures, mouth guards or dental issues that may trap alcohol in the mouth creating inaccurate breath alcohol testing.

Speak to a Drunk Driving Defense Lawyer

Barton Morris is an attorney who is thoroughly familiar with proper testing procedure and the science behind all breath alcohol tests in the State of Michigan and knows how to effectively challenge the tests in court to a prosecutor, judge or a jury.