The victim, identified by USC as Matthew William Olson, was walking on the southbound side of the freeway near 37th Street around 2:45 a.m. Saturday when he was hit by one car, according to an incident report from the California Highway Patrol.
It's unknown why he was walking on the freeway.
Olson was down on the ground when he was then hit by a second vehicle which sped off without rendering assistance, the CHP said. The first car stayed at the scene where Olson was pronounced dead by paramedics.
The 18-year-old was an incoming freshman from Newport Beach who was active in several extracurricular programs, according to a statement from USC. Counseling services were being offered on campus to students, faculty or staff.
Olson attended Corona Del Mar High School. His former high school basketball coach Ryan Schachter issued a statement that reads in part: "His legacy is much more than his incredible achievements in the classroom or in the athletic arena, he was a genuinely kind person and those who were fortunately to have known Matt, and are much better for it."