OAKLAND -- A young skateboarder died Wednesday, two days after he was hit by a car in North Berkeley, police said.

Tyler DeMartini, 18, of Berkeley, died at 4:10 p.m. after spending two days in the trauma center at Highland Hospital in Oakland.

The teen, a student at El Cerrito High School, had been in grave condition since the 7 p.m. accident Monday.

DeMartini was on his skateboard traveling west on Marin Avenue when a 54-year-old man driving east on Marin turned left onto Tulare Avenue and the two collided, said Berkeley police spokeswoman Sgt. Mary Kusmiss.

Police said alcohol was not a factor in the crash, and the driver, who stopped immediately after the collision, was not arrested. The driver's name was not released.

A preliminary investigation determined that DeMartini was in the roadway when the collision occurred, Kusmiss said.

He was the second young skateboarder to die in recent days.

On Sunday, Tucker Hacking, 20, of Walnut Creek died two days after falling from his skateboard on a steep road and hitting his head in a skateboarding accident in Lafayette. Hacking skated at the Walnut Creek Skate Park and friends hope to rename the park the Tucker Hacking Memorial Skate Park.

Neither skateboarder was wearing a helmet at the time of their accidents. Under California law, only those 17 and younger are required to wear a helmet while skateboarding.

DeMartini was the second El Cerrito High School student killed this week. A 17-year-old student at the school was stuck by a train and killed early Sunday morning about half mile west of Cutting Boulevard in Richmond. It has not been determined why he was on the tracks.