The 30-year-old mother was awaiting arraignment Friday after her arrest on driving while intoxicated and child-endangerment charges.
Suffolk County police say the woman's car hit another vehicle traveling alongside her on North 18th Street in Wyandanch around 9:15 p.m. Thursday.
The toddler has been treated at a hospital for minor injuries and released. She's with relatives.
The mother and the two people in the other car weren't hurt.
In a separate case, police say a 36-year-old father was arrested in Levittown Wednesday for driving drunk with his 8-year-old daughter in the front seat.
He faces a charge of aggravated driving while intoxicated.