VISTA, Calif. -- A San Diego police officer who shot a woman and her 8-year-old son during an off-duty traffic dispute in Oceanside must stand trial on a felony charge of gross negligent discharge of a firearm, a judge ruled Wednesday.

Frank White, 28, is accused in the March 15 shooting of Rachel Silva and her son, Johnny, in the parking lot of a Lowe's home improvement store. White is also charged with a misdemeanor count of exhibiting a gun.

After a daylong preliminary hearing, Vista Superior Court Judge Joel Pressman ordered White to stand trial on the charges.

The officer has been on administrative leave without pay since the incident. He faces a total of 9 years in prison if convicted on all counts.

Priscella Bethurem testified she was driving toward a grocery store on Old Grove Road near state Route 76, when she noticed a silver sedan pulling out of a shopping center without stopping, causing a dark-colored car behind her to swerve in order to avoid a collision.

"I thought that they were either drunk or an idiot," Bethurem said of the driver of the silver car.

The witness said she turned right into the next driveway and noticed the dark car behind her and the silver car -- which she thought had turned left -- following closely behind the dark car.

Bethurem testified she saw the silver car pull in front of the dark car at an angle, blocking the path of the dark car.

"You thought there was going to be a problem, didn't you?" defense attorney Rick Pinckard asked the witness.

"Yes," she answered.

Bethurem said she went into the Ralphs grocery store for about 10 minutes and when she came out, the shooting had already happened and emergency vehicles were at the scene.

According to testimony, Silva backed up in her silver Honda and sideswiped White's black Mercury sedan, whereupon he fired five rounds into her vehicle.

Silva was hit twice in the right arm and her son was struck in the left leg.

Silva also had a blood-alcohol level of .15 percent and had used methamphetamine and marijuana, authorities said.

The Attorney General's Office charged her with felony child endangerment and misdemeanor driving under the influence and driving with a suspended license. Silva now faces a total of six years in prison if she is convicted on all the charges.

Deputy District Attorney Julie Korsmeyer told the judge that White "overreacted violently" and was not in immediate danger of serious injury when he decided to fire at Silva's car.

"A reasonable person would not have used deadly force," the prosecutor said.

Pinckard said Silva was armed with a 2,500 pound vehicle and that White fired at her car in self-defense.

The attorney said Silva was close to home and had every opportunity to leave the parking lot, but she instigated the confrontation.

Pressman ruled there was sufficient evidence to have White answer the charges at trial.

"I think we expect more from our officers that the conduct displayed her," the judge said.

He ordered White to return to court Dec. 3 for arraignment and to get a trial date.