A witness to a collision on Interstate 90 was struck and killed by a car while crossing the highway Wednesday morning, Washington State Patrol reported.

The woman was hit in the HOV lane of westbound I-90, west of State Route 900 in Issaquah, state patrol spokesman and Trooper Chris Webb said.

Troopers closed the left two lanes at the scene of the accident while they investigated.

No one else was injured in the collision, Webb said.