The M62 has been closed between Normanton and Rothwell following a collision this morning.
More than six miles of traffic has built up on the westbound carriageway after the incident.
The carriageway has been closed in both directions between junction 30 (Rothwell) junction 31 (Normanton).
A spokesperson for West Yorkshire Police said: "We were called at 8.37am to the M62 westbound to a road traffic collision involving a motorbike and at least one other vehicle.
"A temporary closure was made eastbound to allow for an air ambulance to land.
"This is an ongoing incident."
The incident was first reported shortly before 9am this morning.
An eyewitness said they had seen multiple ambulances on their way to the scene of the collision.
The air ambulance has also attended the incident.
Highways England have provided details on diversions while the road remains closed. Open the Tweet above or click here to view the diversions in full.
Update, 11.59pm: The M62 is expected to remain closed until at least 2pm