Officers responded to a report of a collision involving a pedestrian in the 2100 block of Brittan Avenue at around 8:45 p.m.
Witnesses told police a 1999 Chevrolet Lumina had driven onto the sidewalk and struck a 28-year-old San Carlos woman. The victim sustained serious head wounds, and both her legs were broken.
The driver, a 25-year-old San Carlos woman, was not injured, police said.
Brittan Avenue was closed for nearly five hours while police conducted an investigation.