A blue sign with a diagram showing a branch off the road ahead and the following text.
Forward destinations: Abertawe; Swansea.
Exit destinations: Port Talbot; A4107.
Junction number: 40.
This sign peers at us from over the parapet of the viaduct. If you see it from ground level you realise it's a completely separate structure, mounted on two of the most enormous posts next to some terraced houses, and looks quite ridiculous.