His blood-alcohol content was more than double the legal limit, charges note.
12 people died in the first six days of May.
He's accused of backing over the toddler and fleeing the scene.
"Umm sorry but we are pretty sure that guardrail didn’t want to go for a late night swim."
A man was arrested on suspicion of impaired driving.
The victim was a sophomore at Minneapolis North High School.
The incident happened Wednesday afternoon in rural Walker, Minnesota.
A woman in the same car was also seriously injured.
A+ for the painting skills, but an F for decision-making.