The pedestrian entered Highway 87 at about 8:15 p.m. Friday and threw his skateboard at a passing vehicle, according to the CHP.
CHP said the man, whose name was not released, then ran directly into the path of an oncoming vehicle before being struck by a passing vehicle.
It is unknown why the pedestrian entered the highway, the CHP said.
Traffic came to an abrupt stop after the crash, with three cars colliding, according to the CHP. One driver fled the scene, the CHP said.
Two lanes on southbound Highway 87 between Park and Julian streets were blocked while crews cleared the scene, according to the CHP.
By 11 p.m., all lanes were reopened, the CHP said.