A mother of four accused of driving drunk and causing a crash that killed her fiance and two young women standing outside a parked car on State Route 78 must stand trial for gross vehicular manslaughter and DUI charges, a judge ruled Wednesday.Vista Judge K. Michael Kirkman ruled that the prosecution had presented enough evidence to proceed with the case against 34-year-old Debbie Pacheco Sumi, who faces 16 years in prison if convicted.A Superior Court arraignment was set for March 23.Deputy District Attorney Jodi Breton told a judge at an earlier hearing that Sumi's blood-alcohol level was measured at .34 percent -- more than four times the legal limit -- following the Aug. 13 crash. Also, the defendant did not have a valid driver's license, according to Department of Motor Vehicle records.The chain of events leading to the triple fatality began about 12:30 a.m. when the driver of a westbound 2008 Nissan Altima pulled to the side of the freeway because one of her three passengers was ill, according to the California Highway Patrol.After parking on the shoulder, the driver got out of the car along with another woman and another passenger, 25-year-old Omar Guzman of Oceanside, CHP Officer Eric Newbury said.A short time later, an oncoming 1994 Jeep Cherokee drifted off the freeway and smashed into the Altima and the two women standing alongside it, killing Susana Orozco of Escondido and Erica Oliva of Fallbrook, both 23, and hurling 21-year-old Gerardo Cortez of Oceanside out of the parked car.The Cherokee then skidded across the roadway and overturned, throwing Sumi onto the pavement and partially ejecting her passenger, 34-year-old Larry Alvarez, who died at the scene."I saw a vehicle being pushed, way away from me," said Guzman, who took the witness stand inside the Vista courtroom Wednesday. "I saw another vehicle that was rolling over and began dragging itself on to the center divider.Cortez, who was asleep in the car, testified that he remembers waking up in the bushes and seeing Guzman in a panic."He was standing a couple feet away from the car. He was just sort of screaming, yelling," said Cortez.While Sumi's attorney insisted she was not the one behind the wheel, Breton disagreed."We're confident that Debbie Sumi was driving the vehicle and not her deceased boyfriend," Breton said.The CHP said the injuries to Sumi's chest and abdomen from the crash are consistent with the height of the steering wheel to her body.According to Alvarez's mother, her son lived in North County with Sumi, their two young children and her two elementary school-aged children from a previous marriage.10News learned Alvarez had proposed to Sumi earlier that night and they were on their way home from celebrating in Escondido when the crash occurred.Despite being flung out of the parked car, Cortez suffered only minor injuries, according to Newbury, and Guzman escaped unscathed.Sumi faces 16 years in prison, if convicted.