CANBY, Ore. -- A Keizer woman died in a crash on Interstate 5 on Wednesday morning.

Police said the collision involved a semitrailer and a Lexus, with the Lexus flipping onto its top off the freeway at about 5:15 a.m.

Linda Trethewy was headed northbound on I-5 near a work zone when she began slowing in an attempt to merge into the right lane, police said. Troopers said Trethewy's Lexus hit the side of a flatbed semitrailer.

Trethewy then drove back to the left, through the center median and off a 25-foot drop. The car landed on its top on the Canby/Hubbard Highway, police said.

Trethewy was pronounced dead at the scene.

The truck driver, Justin Boyer, told state police Sgt. Tom Worthy that the collision happened very fast.

"He says he was just entering the work zone and everything happened very quickly," Worthy said. "That's pretty common with a crash like this."

Trethewy was 53 years old.

Boyer was not injured in the wreck.