San Diego Police responding to report of at least two pedestrians struck by a vehicle on I-15 south just north of 163 in the Miramar area.

SAN DIEGO (CBS 8/CNS) - A motorist was killed Thursday after she fell or jumped out of a moving SUV on Interstate 15 in the Miramar area and was hit by at least one other vehicle.

Witnesses reported seeing the unidentified woman tumble out of the driver's seat of a yellow Jeep Wrangler in a middle lane on the southbound side of the freeway near Miramar Way at about noon, according to the California Highway Patrol.

The accident happened right in front of Paige Spence, leaving her visibly shaken.

"It just did something tome to see that," Spence said. "It was so bad. It was just crazy because she was walking, crossing the street and a couple cars hit her. I know it was an accident, but it was terrible. "

"It looks like she came out of her vehicle [and] landed in the roadway," said CHP public-affairs Officer Jake Sanchez. "[We're] not sure how many times she was hit. [We] have some vehicles here and some may have left the scene, as well."

It was unknown if the woman, who was carrying no identification, exited her SUV accidentally or on purpose, Sanchez said.

"Right now we're still looking into speed and those types of things," Sanchez said "We don't have an exact location. She came out of the vehicle about a quarter of a mile of where her vehicle ended up."

The Jeep continued along the interstate for about a quarter-mile before rolling to a halt against a center-divider wall.

Various southbound lanes of I-15 in the immediate area were closed intermittently for about 90 minutes following the fatality. The freeway was fully open again by early afternoon, according to Sanchez.

Spence said after she saw what happened she rushed over to the woman and felt for a pulse, but was so in shock she had a seizure.

"They said [I had] a seizure from witnessing the incident," Spence said.

The victim was later pronounced dead, leaving many wondering how this could have happened.

"It's just tragic," Spence said. "I just can't explain the emotions behind it."