The incident was caught on surveillance video on Monday morning at 8:47 a.m.
In the video, it appears the light turns green for traffic and pedestrians travelling on North 17th Street at East Julian Street.
RAW VIDEO: 12-year-old girl injured in San Jose hit and run collision
The 12-year-old girl started walking in the crosswalk but the car turning left on to Julian doesn't yield to her and hits her. The girl climbs back up to her knees as a car coming the other direction stops and that driver gets out and appears to help out the girl.
The 12-year-old was taken to the hospital with injuries not considered to be life-threatening.
As for the car that hit her, a 4-door Toyota Camry, another surveillance camera shows it pull over briefly on East Julian Street, before taking off.
The driver of the Camry is described as a woman in her 40s or 50s.