Impaired to the slightest is a separate and distinct DUI from the next three higher-level DUIs. It is illegal to drive or be in control of a vehicle if you are impaired to the slightest degree from alcohol, drugs, or other substances.
It is possible to be found guilty of this DUI even if your Blood Alcohol Content (BAC) is as low as a .01 even though the legal limit is .08.
The presumption is that you are not impaired when your BAC is under .08 but you can still be found guilty and suffer the harsh consequences of a DUI if you are found guilty.
The minimum statutory jail time for being impaired to the slightest is 10 days jail.