The incident closed state Route 248 around 7:30 a.m. and reopened about two hours later.
Park City Fire District Battalion Chief Sean Briley said the woman was unconscious and not breathing when paramedics arrived.
An ambulance took her to Bear Cub Drive near Kimball Junction where AirMed could land to pick her up and flew her to the University of Utah hospital in Salt Lake City.
Utah Highway Patrol Cpl. Jared Heywood said the woman was pronounced dead at the hospital.
He said the woman crossed Kearns Boulevard near Cooke Drive, an area where there is no designated crosswalk. There is a pedestrian tunnel nearby connecting the school district campus across state Route 248.
The driver involved stayed on scene and cooperated with authorities, Heywood said.
The Park City School District sent a district-wide email notifying families of the crash and stated students witnessed the incident in front of the school Dec. 19.
The email said mental health coaches are available at schools and encouraged students to reach out for help.
Students who arrived late to Park City High School, Treasure Mountain Junior High and McPolin Elementary would be excused, the message said.
The names of those involved have not been released.
This is a developing story and will be updated as more details are confirmed.
