The driver of a car that killed three children at Camp Pendleton last May pleaded no contest to three counts of vehicular manslaughter. Assistant U.S. Atty. Larry Burns told a U.S. magistrate that Charles M. Smith, 20, drove 42 m.p.h. on a marine base road when he struck the children and the mother of two of the children. The speed limit is 25 m.p.h. Killed were Charmane Ostergaard, 6, her brother Jeremiah, 4, and Annabell Reyes, 6. Deborah Ostergaard, 24, suffered a broken leg and multiple injuries. Sentencing was set for Nov. 7. Smith, a college student, lived on the San Diego County base with his mother and stepfather, who is stationed there.