OKLAHOMA CITY - Oklahoma Highway Patrol is working to notify family of an out-of-state woman killed in a fiery head on collision Thursday morning.
Flames lit up Interstate 40 at Mustang Rd., engulfing a semi-truck.
A woman hit the truck head-on after driving on the wrong side of the highway.
"That was crazy," Katherine Retter said.
Retter and her friend stopped moments after the fiery crash that killed the driver.
"She almost hit us," she said.
Cars dodging her, troopers said the woman came down the Mustang Rd. off ramp and drove nearly a mile down the wrong side of I-40 westbound.
That's when she hit the semi that caught on fire, then bounced into a second semi.
An upsetting scene even for troopers.
"It is very horrific; it's one of the worst ones I've seen. It's just very tragic," Lt. Mark Reynolds said.
For more than six hours, crews worked to clean up 300 gallons of diesel spilled from the produce trucks, backing up traffic for miles.
Now investigators are looking into the crash to see what caused the woman to drive the wrong way for so long.