A valid stop is required under the implied consent statute. The officer then develops reasonable grounds to believe the person was operating under the influence of liquor or a controlled substance. There are several standards of conduct defined in MCL 257.625 pursuant to which persons may not operate a vehicle after consuming alcohol or while under the influence of a controlled substance. The second is the per se crime. Both of these crimes use a BAC of a .10 or more in the definition of the crime.
Testing is defined in terms of both breath and blood now.
This is defined as a presumptive offense at a .08 BAC and can include a combination of liquor or a controlled substance. This crime was to simplify proofs required to establish the crime. It was very narrowly defined. Officers may arrest persons under the age of 21 for any bodily alcohol content. If the person takes a breath test, the test must register a .02 BAC to a .07 for this charge.