One pedestrian has died and another has been hospitalized after two separate vehicle collisions in San Francisco in less than 12 hours.

According to San Francisco Police Department spokesperson Officer Gordon Shyy, a pedestrian was struck by a driver at Columbus and Green Streets at 9:20 p.m. Wednesday night.

Shyy says that the pedestrian was transported to San Francisco General Hospital with life-threatening injuries. An update on the pedestrian's condition was not available at publication time.

The driver remained at the scene, Shyy said, and was cooperating with SFPD investigators.

Then, at 6:15 Thursday morning, a runner who was crossing Van Ness Avenue while "in or near the crosswalk" was struck and killed by the driver of a Golden Gate Transit bus, Shyy says.

The driver was turning onto northbound Van Ness from eastbound Lombard Street when he struck the runner, a woman in her 50s.

She was taken to SF General, and was pronounced dead about an hour after the collision, Shyy says.

According to Shyy, Golden Gate Transit buses are equipped with front-facing cameras. Investigators will examine the footage from this collision as part of the SFPD inquiry into the cause of the crash.

Golden Gate Bridge, Highway and Transportation District spokesperson Priya Clemens says that the driver has worked for the transit agency for veteran over 35 years "with an excellent service record," and that he "is very shaken up."

Clemens says that in addition to the police investigation, Golden Gate Transit will conduct their own, and will test the driver for drugs and alcohol.

“All our hearts at Golden Gate Transit go out to this woman’s family," Clemens said, "and we are cooperating fully with the police to learn what happened in this collision.”