A man and a woman are dead after a wrong-way driver collided head-on with another vehicle on a Lakeside freeway.

The crash happened around 3:15 p.m. on State Route 67 near Winter Gardens Boulevard, blocking all the northbound lanes and prompting a Sig Alert.

California Highway Patrol officials say a 29-year-old female driver from Jamul in a silver Ford F150 truck entered the freeway by going the wrong way on an off-ramp, cutting into the dirt portion that separates the ramp from the freeway. The Medical Examiner's Office later identified the woman as Trista Lynn Stier.

Patric Vargas told NBC 7 he saw the whole thing in his rear view mirror. If Stier had come down the ramp four or five seconds earlier, she may have hit him, he said.

"She got to the middle and squared up facing oncoming traffic and stayed in that position," said Vargas. "That tells me that it was deliberate."

A 49-year-old male driver -- identified as Douglas M. Menegos of Alpine by the ME's Office -- in a Select Electric utility truck was pulling a trailer northbound in the fast lane.

The CHP says Menegos tried to avoid the truck that was coming toward him, but he was not able to swerve fast enough. The vehicles hit head-on.

Witnesses say each vehicle was going about 60 miles per hour, and the drivers were the only ones inside.

The crash caused the vehicles to spin into the traffic lanes, and one collided with a 2002 Ford F450, driven by a 53-year-old man from El Cajon, according to the CHP. That man was uninjured.

Stier was taken to Sharp Memorial Hospital, and Menegos was airlifted to Mercy Hospital. Both died from their injuries.

Multiple witnesses told investigators it appeared that Stier was driving the wrong way intentionally, but investigators are still looking into the incident and cannot confirm that information.

A mattress, tires and other items from the pickup truck were strewn across the scene after the crash.

Vargas calls this crash the worst thing he's ever seen.

"If I would gone to the drinking fountain before I went home, it would have been -- you know -- it would have been me," Vargas said.

He has never been more grateful to be with his family than he was Friday evening, he told NBC 7.