Traffic is crawling on the M1 southbound between Northampton and Milton Keynes following a smash on Thursday morning (August 19).
A car and HGV collided near Newport Pagnell Services at just before 6am.
Highways England confirmed at 7am that all lanes are clear but they expect congestion to linger well into the morning rush hour.
Two lanes were blocked by the shunt on the main carriageway with vehicles also unable to join the motorway from the services slip road.
Traffic was also tailing back on the A45 in Northampton towards the Queen Eleanor roundabout as drivers struggled to join the southbound motorway.