The westbound lanes of Interstate 84 are closed in Eastern Oregon while the wreckage from a pileup of several semitrailer trucks is cleared.
The closure extends from Ontario on the Idaho border to Pendleton.
An Oregon Department of Transportation spokesman, Tom Strandberg, says authorities hope to reopen the westbound lanes later Monday.
The wreckage is on Cabbage Hill, the mountainous stretch south of Pendleton best known as the place where a tour bus plunged down a hillside in 2012, killing nine people and injuring 38.
The pileup last night left vehicles backed up behind the wreckage.
Overnight, authorities closed the eastbound lanes to let backed-up cars get around the pileup. Strandberg said the eastbound lanes would be closed again Monday morning to allow trucks to do the same.