SAN MATEO COUNTY — An 18-year-old San Martin man was killed Thursday in a solo car crash on Skyline Boulevard near Portola Valley, according to the California Highway Patrol.

The collision was reported around 2:10 p.m. north of Alpine Road. The CHP said a 17-year-old San Jose boy was driving a gray 2001 BMW southbound on Skyline Boulevard at a “high rate of speed” when he lost control, crossed the double-yellow lines and left the roadway.

The car then barreled down an embankment and slammed into a tree before coming to a rest on its wheels roughly 40 feet from Skyline Boulevard, according to the CHP.

The 18-year-old San Martin man, who was riding in the front passenger seat, was critically injured and died on the way to Stanford Hospital, according to the CHP. On Friday, the San Mateo County Coroner’s Office identified him as Phillip Restivo.

The driver, who was not identified because of his age, suffered minor injuries, and a second passenger in the backseat — identified by the CHP as Blake J. Carpenter, 19, of Morgan Hill — suffered moderate injuries. They were both treated at Stanford Hospital.

Drugs and alcohol are not suspected as factors in the collision, which remains under investigation.

The CHP closed Skyline Boulevard for about two hours for an investigation. The roadway was then closed for another hour so that the BMW could be removed from the embankment.

Anyone with information about the case can call CHP Officer Christopher Benavidez at 650-369-6261.