The improvement converted the road to grade separated two-lane dual carriageway standard. The British Government at the time decided that a motorway standard M56 extension would be too environmentally damaging, and instead opted to utilise part of the existing road while providing off-line bypasses for all of the at-grade junctions.
The upgrade elevated the road to a two-lane dual carriageway standard, with grade separation. The British government chose not to build an M56 extension due to environmental concerns and instead used parts of the existing road and created bypasses for all at-grade intersections.