The driver of a silver Toyota Prius struck two pedestrians as they crossed the street Saturday evening, leaving one with serious head injuries from which she might not recover.

According to the San Francisco Police Department, a 70-year-old-woman and a 79-year-old man had the green light as they crossed Franklin Street at 11:02 Saturday night.

The 61-year-old driver, who also had the green light, "failed to yield" to the pedestrians, police say, and struck them both.

The female pedestrian suffered traumatic brain injuries that police described as life-threatening. The male pedestrian was left with non-life-threatening injuries to his shoulder. Both were transported to San Francisco General Hospital.

Police didn't immediately have any additional details on the collision, including the cross street at which the collision occurred or the direction in either party was heading. As of Monday morning, police say, the driver has not been cited, detained, or charged in the crash.