Brandon Medina of Poughkeepsie and two other juveniles were in a vehicle driven by 36-year-old Kim Medina, also of Poughkeepsie. It hit a divider on southbound I-287 in Wanaque and overturned around 10:30 p.m. Friday.
Authorities say Brandon Medina, who was in a rear passenger seat, wasn't wearing a seat belt.
Kim Medina, 12-year-old Felix Medina and 1-year-old Christopher Jones were all taken to Morristown Memorial Hospital. Kim Medina was in fair condition, but hospital officials would not provide information about the two children.
The relationship between the driver and passengers remained unclear Saturday afternoon.
The crash, which remains under investigation. shut down a stretch of the highway for several hours.