NORTH COUNTY — One person suffered serious injuries and a driver was arrested on suspicion of drunken driving in a collision on Interstate 5 north of Las Pulgas Road early Friday, the California Highway Patrol said. The accident occurred shortly after 2 a.m. at a rest stop near Camp Pendleton. A witness reported to the CHP that two vehicles collided and one, a van, went down an embankment, into some bushes. One injured person was taken to a trauma center. One driver was taken to Vista Jail for booking on suspicion of drunken driving, the CHP said.