Ashleigh Jackson, 24, was riding on Highway 9 near Fruitvale Avenue in Saratoga with her boyfriend Dave Nelson when they were both hit by a late-model, silver, 4-door BMW.
Nelson's injuries were minor, but Jackson, a West Valley College student and member of the Alto Velo cycling team, was thrown from her bike. Jackson was taken to a San Jose hospital where she was treated for head trauma.
Police say the accident would have damaged the car's passenger side mirror.
Boccardo Management and Essex Property Trust have contributed to what is now an $11,000 reward for information that leads to an arrest in the case.
Anyone with information is asked to call the Santa Clara County Sheriff at (408) 808-4400.