Motorway lane allocation sign
A blue sign with a diagram showing the left lane exiting and three others continuing, and the following text.
Left lane destinations: Denby; Dale ; A636.
Right-hand three lanes destinations: The SOUTH; Barnsley M1 .
Junction number: 39.
Our fourth lane disappears here, and we return to a conventional three-lane motorway until we hit the outskirts of Sheffield.
Denby Dale, by the way, is famous for repeatedly breaking the world record for the largest pie.