Michigan DUI Evidence: Michigan OWI Evidence

Michigan DUI law permits the police to request a chemical test of a DUI suspect's blood, breath, or urine for purposes of determining blood alcohol content (BAC). Which test they will request is in the discretion of the police. Certain limitations apply, however, and certain tests will be requested over others depending on the circumstances of your case.  Below you will find information about the different chemical tests that are used in Michigan. Consult with an experienced local attorney in your area for more information.

BREATH TESTING

Breath testing is the most common method used to measure a DUI suspect's BAC. There are two types of breath tests that are used in Michigan - Portable Breath Tests and Evidentiary Breath Tests.

Portable Breath Testing (PBT) - PBT's are handheld breath testing devices that are administered on scene prior to arrest. They are not as reliable as evidentiary breath tests, so their results are not admissible in court. Instead, the PBT results are solely used to help the officer determine whether there is probable cause for a DUI arrest. Individuals that refuse to submit to a PBT will be subject to a $100 fine.  DUI suspects under the age of 21 will also have 2 points added to their driving record if they refuse a PBT. DUI suspects operating commercial vehicles who refuse a PBT will be charged with a misdemeanor punishable by up to 93 days in jail and/or a $100 fine.

Evidentiary Breath Tests - The second type of breath test is called an evidentiary breath test. This test is conducted at the police station on breath machines called the "DataMaster."  The DataMaster is a large testing unit, and it is considered more reliable than handheld PBTs. Thus the results of evidentiary breath tests are generally admissible in court. Persons who refuse to submit to an evidentiary breath test risk the suspension of their driver's license and the addition of points being added to their driving record. Please see the Michigan Driving tab for more information.

BLOOD TESTING

Blood testing is considered the most reliable method of measuring a person's BAC. Blood testing is permitted in Michigan DUI cases in certain circumstances. If the police obtain a warrant, the police may forcibly draw a sample of your blood for testing purposes, even if a DUI suspect refuses. Persons who attempt to resist a court ordered blood draw may be charged with obstruction, which is a felony offense. Individuals that have been taken to a medical facility following a DUI related accident may also be subject to a blood test. Michigan law permits any blood samples that are taken for treatment purposes at medical facilities to be tested for DUI purposes. The results will be admissible in court, regardless of whether the individual consented to a blood draw or was even aware that one occurred.

URINE TESTING

Urine testing is typically only requested in DUI cases where the police suspect impairment by drugs. It is not the most reliable method, however, as particular levels of drugs and metobolites are not detectable through urine analysis. Urine tests may also be requested where blood tests are not available (like if the suspect is a hemophiliac) and where breath tests are not practical (because breath machines cannot measure drug impairment, only alcohol).

ADDITIONAL INDEPENDENT TEST

If a DUI suspect submits to the chemical test(s) requested by the police, then they have a right to an additional independent test of their blood, breath, or urine to be administered by a person of their choosing within a reasonable time after their arrest.