An appeal for witnesses has been issued after a serious crash on the M5 northbound near Bristol.
Police said a black Ford Mondeo hit the central reservation and overturned near Clevedon, between junctions 19 and 20, at about 0655 GMT.
The male driver was badly injured and taken to Frenchay Hospital, near Bristol.
Three lanes of the northbound carriageway were closed, causing tailbacks past junction 21 in Somerset.
A police spokesman said the delays lasted for several hours. Anyone who saw the crash is asked to contact the force.