Four lanes of southbound U.S. Highway 101 in Burlingame were closed early Wednesday morning while the California Highway Patrol investigated a fatal accident involving two vehicles and a pedestrian.

Reports of a person lying on the ground in the fast lane of Highway 101 just north of Broadway came into the CHP communications center at about 1:25 a.m., Officer Peter Van Eckhardt said.

Initial reports indicated that a black BMW and a pickup truck were somehow involved, although Van Eckhardt said it was still unclear how the pedestrian came to be on the roadway.