Drivers are being warned to expect queues on the M1 and A45 at Northampton throughout rush hour on Friday morning (February 4) following a crash.
Reports say the shunt is on the southbound side near to junction 15
National Highways traffic sensors show tailbacks on the motorway back to junction 16 and on the A45 towards Queen Eleanor Roundabout.
A spokesman for the agency said congestion could continue until 8.30pm.