A 25-year-old man is in hospital after his motorbike collided with the central reservation of the M621.
The crash happened just before 4am on Saturday morning on the eastbound carriageway near Gildersome.
The road was closed until around 11am while police worked at the scene.
Biker suffered serious injuries after being run over be his friend in road rage row
The biker had been travelling east on the M62 before exiting at junction 27 and joining the M621 towards Leeds.
The rider suffered serious injuries and is now in hospital.
Anyone who witnessed the collision, or has any dashcam footage is asked to contact the police online via www.westyorkshire.police.uk/contact-us or via 101 quoting log number 278 of 31 August.