The 19-year-old freshman, Eloi Vasquez, died early Saturday on eastbound Interstate 10 about a mile from the University of Southern California after he was seen leaving a fraternity party.
A woman said a man ran in front of her and she was unable to avoid hitting him, said Officer Edgar Figueroa, a CHP spokesman. The man was struck just east of Vermont Avenue. The investigation is ongoing.
Vasquez was pronounced dead at the scene. He was not carrying identification, which set off a missing persons search until the coroner could identify him.
Vasquez, who was on spring break in Los Angeles, had left the party to take a walk with no money and no wallet, family and police said.
His mother, Wendy Margolin, said he later called a friend, telling her he was lost and in trouble.
The family had offered a $100,000 reward for information about his whereabouts.
"Eloi is a wonderful young man who has excelled both academically and athletically here at Cal," the university said in a statement before the death was confirmed.
Teammates are expressing their sorrow over the death of a UC Berkeley soccer player who went missing from a Southern California fraternity party over the weekend. On Monday, the Cal Athletics Department tweeted a message that said: "Today we lost a beloved member of the #CalFamily, Eloi Vasquez. We send thoughts & prayers to his family & friends."
The entire soccer community came together over the past couple of days during the search for the 19-year-old. And now, they are coming together in their grief with MLS teams, NCAA, and even the Pac-12 tweeting out their condolences.
On behalf of the Quakes, our condolences go out to the family & friends of @CalMensSoccer player & Marin County native Eloi Vasquez.— San Jose Earthquakes (@SJEarthquakes) March 30, 2015
"Eloi was a wonderful teammate," said UC Berkeley Soccer Coach Kevin Grimes. "He was very close to all of his players and our guys are grieving pretty hard right now."
Our condolences to the family of @CalMensSoccer player Eloi Vasquez.— LA Galaxy (@LAGalaxy) March 30, 2015
The entire Pac-12 mourns with @CalAthletics over the loss of soccer student-athlete Eloi Vasquez. Our thoughts are with his family & friends— Pac-12 Conference (@pac12) March 31, 2015
Heartbroken to hear of the loss of one of my fellow Golden Bears. Prayers up for Eloi's family and those blessed enough to have known him.— Christian Behrens (@CBehrens14) March 31, 2015
Our sincere condolences to the family and friends of Eloi Vasquez and the @CalAthletics family.— Washington Huskies (@UWAthletics) March 30, 2015
My heart goes out to the friends and family of Eloi Vasquez, and to @CalMensSoccer. So sorry for this terrible loss.— Nicholas B. Dirks (@nickdirks) March 30, 2015
KGO-TV in San Francisco contributed to this report.