The open-top, double-decker bus ran down a bicyclist, two pedestrians and at least four vehicles before plowing into scaffolding at a construction site. Police said at least 30 people were aboard the bus. Four people were treated at the scene and 16 others were taken to the hospital.
San Francisco Police Officer Albie Esparza said the bus started picking up speed before the crash. It is not clear what led to the incident.
