Is the evidence against you legal (in violation of your legal rights)?
Police officers can make mistakes. The police officer could have formed incorrect opinions of your sobriety, violated the administrative rules and methods of testing your BAC (blood alcohol level) or illegally arrested you without probable cause. Furthermore, the police officer could have pulled your vehicle over in violation of your right to be free from unreasonable searches and seizures (4th Amendment of the Constitution).
Evidence should be demanded right away so that your attorney can put each piece of evidence to the test and weaken the prosecutor's case against you. Knowing how to defend a DUI case involves considerable preparation, familiarity with the law and science, using effective legal strategies and knowing what motions to make and when.
In evaluating a DUI case, your attorney needs to gather all of the necessary evidence as well as understand and review the jury instructions, case law & proposed legislation in MI.
Will the Prosecutor's evidence prove you guilty beyond a reasonable doubt?
Just like any other criminal charge, a DUI charge is a jailable offense which can deprive your liberties, therefore, the Prosecutor is required and MUST prove each and every element of a DUI case beyond a reasonable doubt' at trial.
Beyond a reasonable doubt is the highest standard of proof that must be met in any trial. In civil litigation, the standard of proof is either proof by a preponderance of the evidence or proof by clear and convincing evidence. These are lower burdens of proof. A preponderance of the evidence simply means that one side has more evidence in its favor than the other, even by the smallest degree.The reason that the high proof standard of reasonable doubt is used in DUI and criminal trials is that such proceedings can result in jail/prison. These outcomes are far more severe than in civil trials, in which money damages are sought.
Did the police follow the law and administrative rules or procedures?
There are laws that protect drivers and administrative rules that are in place to ensure that police follow. For example, a police officer must read a suspected drunk driver their "chemical test rights" before administering the Breath Test. Also, prior to administering the Breath Test, the police officer must observe you for, at minimum, 15-minutes prior to administering the Breath Test to ensure that you are not regurgitating, putting an object or your finger(s) in your mouth, vomiting or doing something that would make the BAC Test results unreliable.
Another example is whether the police "stopped" your vehicle without any evidence of a civil infraction or 'bad' driving. These are situations where police officers pull a vehicle over based on a hunch that the driver may be drunk without more.
Police must follow the law and administrative rules otherwise a good DUI Lawyer can challenge the police actions through motions to suppress and dismiss.