After an A1(M) crash at the Welwyn Garden City exit, two people were taken to Lister Hospital in Stevenage yesterday.
Two lanes are closed on the A1(M) after a crash involving four cars between Welwyn and Stevenage this afternoon.
Northbound traffic was stopped on the A1(M) last night after two crashes involving multiple vehicles near to Junction 6 for Welwyn.
There were long delays on the A1(M) northbound this morning due to a crash near the Welwyn junction.
The A1(M) has fully reopened northbound after two crashes near Junction 2 shut the motorway this afternoon.