A state trooper stopped a minivan for speeding early Saturday on U.S. 30 in Schererville in northwestern Indiana. He arrested the 24-year-old woman on drunken driving charges.
The boy's father arrived later to pick him up, but officers determined he was intoxicated and also arrested him on a drunken driving charge.
Police said the boy's grandparents then arrived. Both of them also had been drinking, state police said, but the grandmother who was driving was not over the legal limit, so officers escorted them home with the child.