Police made the discovery at about 10 p.m. Thursday during a traffic stop. The three children were in the storage area above the cab of the rented U-Haul van.
State law requires children to be properly restrained within a vehicle's passenger compartment.
The three children were unhurt. They were handed off to other family members.
Police said the mother, Jennifer Nolan, who was driving with a suspended license, was not only guilty of bad judgment. Authorities who examined her children said they discovered evidence pointing to other forms of abuse.
Nolan was charged with child neglect.