The crash happened just before 4 p.m. Thursday on Hempstead Turnpike near Shelter Lane in Levittown.
Police say 14-year-old Teresa Vargas was on her way home from school, crossing the very busy Hempstead Turnpike against the light, when she was struck.
Vargas was walking with her classmates, who waited at the curb while she decided not to wait for the green light.
A brown or tan car struck Vargas with such force that she was thrown into the air.
The vehicle fled the scene as the girl was struck by two other vehicles.
Those drivers remained at the scene.
Vargas is in the hospital with multiple trauma injuries.
There is surveillance video so far. Investigators are checking nearby red light cameras to see whether they can isolate a shot of the car.
Police ask anyone with information regarding the incident to call Crime Stoppers at 800-244-TIPS. All calls will remain confidential.