Complex sentence: Fishguard Trunk Road in 1936 only included the A48 and the A40, however with road improvements most notably the M4 motorway, the A48 in south Wales and A40 in England have largely been de-trunked.
Split into simpler sentences: Fishguard Trunk Road in 1936 only included the A48 and the A40. However, with road improvements (most notably the M4 motorway), the A48 in south Wales and A40 in England have largely been de-trunked.