Traffic is building up on the M6 near Forton after a van lost control on the sliproad before hitting a bridge.
Police say the driver of the vehicle lost control on the wet surface.
The collision caused the van's flat-bed trailer to be ripped from the vehicle.
No-one was injured but traffic is backing up to near Garstang.
Witnesses say there has also been a collision close to junction 32.
Meanwhile, a slip road from the M55 eastbound to the M6 northbound at Broughton was closed earlier this afternoon following a collision.
The lane has now been reopened but traffic is slow as officers remain on the hard shoulder while recovery is underway.