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Preliminary Breath Test (PBT) vs. Data Master (DM)

I am often asked by my clients what my advice would be if I were sitting next to them at the time they are pulled over. Would I advise them to submit to a PBT or not? Should he/she submit to a Data Master breathalyzer? What is the difference?


OWI, super drunk/high BAC, or Impaired Driving, otherwise known as drunk driving, are serious offenses in the State of Michigan. The ultimate outcome in an OWI (Operating While Intoxicated) or drunk driving case can ultimately depend on the knowledge you have at the time of the stop and your attitude at the time you are pulled over.


When interacting with law enforcement one should always do it respectfully and courteously. The time to fight or argue, is in court and should be left up to your attorney whom should have in depth legal knowledge and the law backing your case. However, you would like to balance this with knowing your rights as well.


When an officer suspects a citizen of driving drunk or operating while intoxicated by another substance, they make a stop with the intent of creating “probable cause” to make an arrest. An officer can only make an arrest if “probable cause” is raised in the officer’s mind. One way “probable cause” is determined is through observing a suspected drunk driver while completing what’s called field sobriety test or FST‘s. These are a coordination test designed to raise “probable cause” in the officers mind. The PBT or preliminary breath test, is a tool that raises “probable cause” as well, and the number it produces is typically a heavily weighed factor for the officer when making a determination to arrest. Putting everything together that the officer observed during the traffic stop, the FST‘s, and the PBT, the officer will ultimately make a determination whether “probable cause” is met. If a PBT is refused the officer can not make you take it, and so would not have the PBT number to go by, only his observation.


Refusing a PBT is merely civil infraction punishable by up to a $250 fine in most counties. It is a very important tool in the officer’s mind in the determination whether you were over the limit. However, a PBT is not as accurate as a chemical test, which is very different from a preliminary breath test. Because it’s not as accurate as the chemical test breathalyzer (also known as a data master) the preliminary breath test is usually non-admissible in court. There are exceptions to this rule and can be found under MCL 257.625 a(2)(b).


So, because PBTs are usually not admissible in court, and they are such a heavily weighted factor in the officers’ determination of whether you are under the influence, I always advise my clients NOT to submit to a PBT.


Again, this is different from a chemical test. A chemical test is offered to you after an arrest is made meaning “probable cause” has already been determined. Usually an officer will request that you consent to a chemical test. A chemical test is either a blood, urine, or data master test. The data master is another type of breathalyzer that is stored typically at the jail or police station. This chemical test/breath test is considered to be much more accurate by the courts and is usually admissible in court for purposes of trial.

As such, Michigan has what’s called implied consent laws. It can be explained that these laws basically mean that because you own a license to drive in the State of Michigan and by signing your name and excepting that license, you give “implied consent” that you will comply with a chemical test request given by a police officer. So, if you ultimately do not submit willingly to a chemical test; you could be subject to what’s called an implied consent suspension. What this means is that the Secretary of State (SOS) will suspend your license for a period of one year. If you are being asked to consent to a chemical test, you should receive a form called a DI-177 form. This form is meant to inform you of what a decision to decline a chemical test can cost you. Basically, it can cost you your license for a year, so before making that decision make sure you realize what the ramifications can be.


There are ways to appeal these implied consent suspensions. One option must be done quickly, usually within 14 days. Other appeal tools can be written after 14 days so even if you did not talk to me right away, we still may be able to appeal due to a hardship. Please contact me right away to discuss your options in your case.


If you find yourself in any type of situation because of an OWI or drunk driving arrest please call Slep Legal Group, PLC. We can certainly help with all aspects of drunk driving, OWI, license suspension, implied consent suspensions, hardship appeals, driver license restoration, and/or traffic tickets and violations.

We are here to help you.

#forthepeople #thegoldstandardlawfirm #justicerequiresit #michigancriminaldefenselawyers

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