Motorway cantilever sign
A blue overhead sign suspended over the motorway from a post on the left, with a diagonal arrow pointing up and left, and the following text.
A57 [Solid triangle diversion symbol] ; Sheffield (SE); Rotherham (S).
Junction number: 31.
This junction might be useful for the south eastern suburbs of Sheffield - which sounds very specific but covers quite a large urban area - but if you want any part of Rotherham you'll have a much nicer time staying on the M1 for a couple more exits.