Michigan Drunk Driving Boot Camp
A fruitful area of cross-examination is the operators lack of knowledge if the machine is working properly. The operator will surely say the machine was built to inform the operator if it is not working, but most operators have not checked whether this safeguard actually works; if the test itself can have an error, so can the mechanism that identifies errors.
DataMaster operators are not trained to identify errors, which leaves a major hole in their testimony. This is like someone knocking on your front door and telling you there is a fire in your home, but you respond with "no there's not, my smoke alarm would have told me about a fire".
Another fruitful line of questioning are the calibration records contained in a log book; the DataMaster is inspected and calibrated about every two weeks, but the operator is not trained to calibrate or inspect the machine when offering a test so there is no way to know if the machine is working properly during the days in-between. There is reasonable doubt that the machine was working properly between calibrations, and the operator cannot firmly counteract that possibility.
Creating reasonable doubt as the accuracy of the results can be very effective in a case where the test results are close to the legal limit of 0.08 for an Operating While Intoxicated charge, or the legal limit of 0.17 for a Michigan High BAC charge.
The prosecution may have civilian witnesses testify against you. These witnesses might be other drivers, pedestrians or employees of bars and restaurants. The common theme with these witnesses is typically inexperience in testifying.
Civilian witnesses typically testify to offer prove that the defendant was driving, usually in an accident case. The typical civilian witness is subpoenaed to court, carefully prepared by the prosecution, and feels a civic duty to "help" the prosecution prove their case.
This witness might testify about driving, observations of possible intoxication and any statements made by the defendant. If this witness is injured or property is damaged then they will testify about injuries or the damage suffered from the incident.
As the defendant in the case, you will have the best information about this civilian witness; you may also have information about pending lawsuits, and based on your prior interactions, the general demeanor of this witness toward your case.
An experienced Michigan DUI attorney will treat this witness with respect, but aggressively challenge the testimony. The civilian witness testimony is usually not based on an outright lie, but rather a mistaken observation or an assumption that is actually false.