Officers responded to a report of a pedestrian hit by a car at 5:06 p.m. on Blossom Hill Road just east of Oak Rim Way.
An initial investigation indicated that the woman was walking on the north side of Blossom Hill Road when she decided to cross the street, police said.
As she walked into westbound lanes, a vehicle in the No. 2 lane slowed down but a westbound vehicle in the fast lane over struck her, police said.
The woman suffered multiple broken bones and severe head trauma and was transported to Santa Clara Valley Medical Center for treatment. This morning, she remained in the hospital's intensive care unit.
The driver of the vehicle that struck her, a 19-year-old woman from Los Gatos, told police her view of the pedestrian was obstructed by the car in the No. 2 lane. She was not injured and hasn't been cited.
The accident remains under investigation. Police said there is no crosswalk at the spot where the woman was hit.
Blossom Hill Road was closed between Los Gatos Boulevard and Oak Rim Way until about 11 p.m. Tuesday.