Awful. While the course was "open", having been to enough VeloPromo events, I'll assume they had flaggers, signs, support vehicles, etc out there. This should not have happened.

edit: CHP's comments are quite upsetting. In multiple articles they're quoted as saying the driver followed the law. I was under the impression that when overtaking another vehicle (including a bike) it must be done so in a safe manner including making sure there is no oncoming traffic. If there was a car/truck/tractor/etc coming toward the driver, would they have made that pass?? Also, law states that bikes must ride to right as practicable and includes provisions to move to the left to avoid hazards, having been on that road multiple times I can say it is rife with hazards leading people to ride closer to the centerline.