A teenage driver was killed in a car-to-car shooting at a freeway off-ramp early Thursday in the latest in several recent fatal roadway attacks in California.

Samantha Padilla, 19, of Los Angeles, was shot in the upper torso around 12:30 a.m., authorities said.

She apparently was attacked while stopped at a traffic light at the end of an off-ramp from the 110 Freeway in South Los Angeles, police Detective Tommy Thompson said. A car pulled up alongside and someone fired about five rounds from a medium-caliber gun, he said.

It appeared Padilla was heading home from Los Angeles International Airport, where she worked, officials said.

"We don't know if this was a personal thing or if it was road rage," Detective Kelle Baitx said.

Car-to-car shootings are not uncommon in the area, Baitx said. He said that although such violence is often gang-related, he did not think Padilla was connected to any gangs.

Thompson said two witnesses had given conflicting statements about the make of the shooter's vehicle. He said he was trying to locate stores with surveillance footage of the area in an attempt to gain additional clues.

Southern California has had a spate of shootings on major roadways; at least five other people have died in recent weeks.

Among the victims were a 54-year-old chiropractor who died after she was shot in the head while driving on Interstate 10 in eastern Los Angeles County; a 26-year-old man who died in a shooting on U.S. 101; and two teenage boys who died after they were shot on a state highway in San Diego County. Another death is being investigated as a possible suicide.

In Northern California, a driver was killed Wednesday in a rush-hour shooting on a San Francisco freeway as he drove with two children in the car.

The attacks remained unsolved but officials say they are unrelated.

"There's really no pattern, they seem just random," California Highway Patrol spokeswoman Officer Heather Hoglund said.