The wreck happened in the 12300 block of Riverside Drive at about 2 a.m. Police said a man in his 20s left his car at the scene and took off.
"What I saw was this car. I saw him impact the car and then his car jumped and came all the way over into this lane where it's sitting right now," described witness Marsha Mann-Pera.
The injured woman, who is believed to be in her 60s, was taken to an area hospital with fractures in both of her legs.
If you have any information regarding this crash, you're urged to call LAPD's Valley Traffic Division at (818) 644-8010.