The child had been in critical condition since being thrown from the car on the I-85 overpass to U.S. Highway 70 on Dec. 1.
The driver lost control of her vehicle in a curve and the car rolled over, struck a guardrail and concrete barrier, officials said.
Three other children — a 3-year-old, a 6-year-old and an 8-month-old — were also injured in the accident but are expected to be OK.
Investigators said that speed was a factor in the crash and that three of four children in the car were not wearing seatbelts. There was no evidence that the driver was impaired, officials said.
Officials also said that charges are pending, but did not say if the driver would be charged. A press release says that the driver was a woman, but police did not say if the woman was the mother of any or all of the four children. Durham police also did not release identity of the driver.