WILSONVILLE, Ore. -- A car went off a 25-foot drop Wednesday morning, killing the driver and slowing traffic on Interstate 5 south of Wilsonville while police investigated.

The deceased woman was identified as 53-year-old Linda Marie Trethewy of Keizer.

According to Lt. Jason Bledsoe, preliminary information indicates a group of vehicles was heading north on I-5 in the area of a highway work zone at 5:15 a.m. when one of the vehicles, a Lexus four-door passenger car driven by Trethewy, began to slow and attempted to move to the right.

The Lexus struck the side of a flatbed semi-trailer pulled by a commercial truck, then traveled into the center median, through a tall grassy section and off a 25-foot drop.

The car landed on its roof on the Canby/Hubbard Highway, killing the driver.

The southbound Canby/Hubbard Highway exit from I-5 was re-opened about 10:30 a.m. All lanes of I-5 reopened by 12:30 p.m.