The legal system is already confusing, right? That's why my profession exists, but you should still educate yourself on the different charges that are possible if you or someone you know is pulled over for driving under the influence of alcohol or drugs. Let's see if we can map this out in simpler terms.
In Michigan, if you are stopped by a police officer for driving under the influence of alcohol, the formal charge you could be faced with is called an OWI; “operating while intoxicated.” Casually, this is referred to as “DUI” or “driving under the influence.” DUI and OWI are interchangeable and they mean the same thing. If you are caught operating a motor vehicle or watercraft with a BAC (blood alcohol content) higher than .08% which is the legal limit in Michigan you could be charged with an OWI.
There is another possible charge called OWVI; “operating while visibly impaired.” This is a driving offense that you could be arrested for regardless of if you're over the legal BAC. It means that there are observable dangers to yourself or others on the road because of your driving. A police officer has the right to arrest you if they observe that you are driving while impaired and no proof that your BAC is over the limit is required, however the prosecutors must be able to prove your guilt and reasonable cause for being pulled over in the first place.
OWPD or “Operating with the Presence of Drugs” is the same type of charge as OWVI but denotes that your driving ability was impaired due to the use of illegal narcotics (drugs that have no approved medicinal use) regardless of how much of the drug you had used. Again, prosecutors must be able to prove your guilt and reasonable cause for being pulled over.
Although these charges might seem to have small differences, those differences require unique courses of legal action for each one. You can't just rubber-stamp an outcome onto each OWI/OWVI/OWPD because so many other factors play a part in the legal strategy that should be taken. This is why it's imperative for you to hire knowledgeable and experienced legal counsel to help get you through the process and obtain a favorable outcome if you are ever faced with any of these possible charges.