Knowles was driving a Volkswagen Jetta and Donselman was a passenger in the vehicle, Hallock said.
According to the preliminary investigation, Knowles was trying to pass a 15-year-old student driver in a Mini Cooper northbound when the Volkswagen crashed into a southbound van, Hallock said. That stretch of Coast Highway is one lane in each direction.
A 49-year-old man and 50-year-old woman in the van were taken to a hospital. A 53-year-old woman in a Honda that was also involved in the crash was also taken to a hospital, Hallock said.
The teen driver was treated at the scene and released and his instructor was unharmed, Hallock said.
Hallock said investigators believe alcohol was a factor in the crash but they were awaiting the results of toxicology tests for confirmation, a process that could take several weeks.