The M1 was closed for three separate spells on Monday because of a variety of crashes between Junctions 4 and 8.
Two men were killed and four other men were injured after a smash between Junction 4 and 5 at 2.40am.
At 11.15am a bus carrying six passengers and a lorry collided between Junction 8 and 9 northbound. No one was seriously injured but the outside and middle lanes were closed for more than two hours.
At 11.55am a man and a woman were taken to hospital when a lorry and three cars crashed between Junction 6a and 6 southbound.
The Highways Authority has said there was no connecting factors in the accidents.