Delays on the A45 in Northampton were caused by two crashes 40 minutes apart.
The first happened at 7.25am on an exit slip road at Riverside.
Three cars were involved and the resulting blockages of the carriageway saw queues back to Barnes Meadow.
Then at 8.05am a car bumped the back of another at the Barnes Meadow roundabout - on the exit slip road leading to Brackmills - causing further delays.
No serious injuries were caused as a result of either crash, a spokeswoman for Northamptonshire Police said.