An accident involving two lorries is causing delays on the M1 northbound near junctions 17 and 18.
Traffic is moving slowly as lanes one and two are closed while recovery work is undertaken.
Highways England estimate a return to normal traffic conditions at around 11.15am. The incident was first reported at 7.50am.
A separate incident involving a vehicle fire is also causing delays of around 15 minutes on the M1 northbound near Watford Gap services.
Lane one is closed at the start of the exit slip road into the service station so that services can deal with the fire. Vehicles can still access Watford Gap after the fire.
Highways England expect normal traffic conditions to resume at 9.30am.