Driving under the influence is classified as a misdemeanor unless the DUI meets certain state-specific criteria such as:
It's not the first offense. Anyone arrested for DUI who has been convicted of driving under the influence previously may be charged with a felony, depending on the length of time since the last conviction.
The offender was driving without a license. Getting a DUI with a license that has been suspended, revoked, or restricted is a felony in many states.
The DUI resulted in someone else's injury or death. Some states cite bodily harm as one of the reasons to change a DUI from a misdemeanor to a felony.