The crash happened on the northbound stretch of the motorway between Junction 22 for Burnham-on-Sea and Junction 21 for Weston-super-Mare.
Traffic was held in the immediate aftermath of the crash, but was released at about 8am.
However, Highways England warned of “long delays” because of the backlog of traffic waiting to get along the trunk road.
It tweeted: ” There is approx. 11 miles of slow moving traffic. Please add an extra 45 minutes on to your current journey time.”
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