The westbound A14 has been closed after two accidents on the approach section to the junction with the M1 and M6.
Both involve damage to vehicles but there were no serious injuries, Northants police said.
Three cars were involved in the crash nearest the junction. The road was also blocked near Welford where four heavy goods vehicles collided.
Police said it would take some time to clear the road as the load from one of the lorries has spilled.
Diversions are in place via the A5199, although this is causing congestion and difficulties in nearby villages including Welford.