The westbound carriageway of the M62 in West Yorkshire remained closed on Saturday evening after a serious crash, National Highways said.
Both carriageways of the motorway were closed after the collision at about 15:20 GMT between junction 24 for Huddersfield and junction 25 at Brighouse.
The agency reported hour-long delays and there was congestion on diversion routes.
The eastbound carriageway reopened at about 20:20, but the westbound side remained closed while an investigation was carried out.